Actuators and Control Systems for Turbomachinery
Turbomachinery Control Systems, Turbine Actuators and Control Systems, Actuation and Controls
Voith actuators and control systems ensure that gas turbines, steam turbines and compressors can be operated more efficiently, safely and reliably.
Our product portfolio includes:
- Actuators
- Turbomachinery control systems
- Turbomachinery protection systems
- Engineering, service and retrofitting
We not only offer components, but also complete solutions – hardware and software, all from one source. An advantage that simplifies a lot and lowers costs. The control system of turbines and compressors runs smoothly.
I/H Converter
DSG I/H Converter
Current to Pressure Converter (CPC), Electro-hydraulic Converter, Electro-hydraulic Actuator Control for Steam Turbines and other Applications

I/H converters change a constant input pressure into a variable output pressure. A standard 0/4 – 20 mA signal specifies the output pressure.
The major components of the I/H converter are a hydraulic unit and a
force-controlled electromagnet.
The I/H converter features a simple and compact design. This ensures reliable operation. The Mean Time Between Failures (MTBF) for Voith
I/H converters is over 600 years. Your equipment runs for a very long
period of time without unplanned downtime; availability is increased.
The I/H converter (CPC) is also available in a redundant design
(hot redundancy): DSM I/H Converter Module (DX-CPC).
Specifications
Flow rate | Up to 140 l/min [37 gpm] at 1 bar [14.5 psi] differential pressure |
Input pressure | Up to 70 bar [1,015 psi] |
Maximum output pressure range | 0 – 35 bar [0 – 508 psi] |
MTBF (Mean Time Between Failures) | 600 years (calculated in accordance to MIL‑HDBK‑217 and Siemens SN 29500, actual MTBF evaluations from installed products show even higher values |
Supply voltage | 24 VDC |
Current consumption | 1.0 A (3.0 A for t < 1 s) |
Input signal | 0/4 – 20 mA |
Fail-safe operation | Fail-safe position through output pressure |
Explosion proof rating (optional) |
|
Protection class | IP 65 |
Safety integrity level | SIL 2 |
Advantages and benefits
- The Mean Time Between Failures (MTBF) is over 600 years. Your equipment operates very reliably. Productivity increases and the costs associated with lost production remain low.
- Voith I/H converters are insensitive to contaminated pilot oil. Turbine lubricating oil is suitable as the operating fluid. One oil supply system for both lubricating and pilot oil suffices. Maintenance is simple, which helps you lower operating costs.
- Very good control response, almost no hysteresis and a resolution better than 0.1% ensure very fast and accurate control. You benefit from having a stable process with high product quality.
- Connections are industry-standard. This means the I/H converter can be integrated into your equipment easily. Standard adapter plates are available to allow the I/H converter to interface with systems designed for Woodward CPC and CPC‑II converters.
You reduce the costs for system integration. - The output pressure range can be adjusted easily on-site by means of potentiometers.
This allows you to adjust the output pressure for the application quickly and without any delays. - For use in hazardous areas, we offer explosion proof I/H converters with the required certificates.
Typical fields of use
- Operation of the control valve of
- steam turbines
- gas turbines
- compressors
- Retrofit of mechanic-hydraulic valve controls
- Upgrade of systems with Woodward CPC or CPC-II converters
Product inquiry
Technical Information
Design

Functionality
With the aid of a controller, a force FMag is generated in a 24-V DC magnet. This magnetic force is proportional to the 0/4 – 20 mA input signal. The desired output pressure range is set by means of two potentiometers X0 and X1. The combination of electronic control, measurement of the magnetic flux, the physical design of the magnet and hydraulic pilot control results in an almost hysteresis-free, dynamic functional unit. The control magnet applies the force FMag to the control piston. This force acts in opposition to the hydraulic force FHydr, which results from the pressure at the A port applied to the face of the control piston (pressure balance). As a consequence of this control, the exactly required pressure and oil flow needed to position the steam or fuel valve are always available in the output line A of the I/H converter.

Control schematic

Selection table
Typ | Maximum input pressure [bar] |
Control range of the output pressure [bar] |
Flow rate [l/min] at 1 bar differential pressure |
|
P > A | A > T | |||
DSG -B03XXX | 40 | 0 – 3 | 30 | 30 |
DSG -B05XXX | 40 | 0 – 5 | 30 | 30 |
DSG -B05X48 | 20 | 0 – 5 | 100 | 140 |
DSG -B07XXX | 40 | 1 – 7 | 30 | 30 |
DSG -B10XXX | 40 | 0 – 10 | 30 | 30 |
DSG -B30XXX | 70 | 0 – 30 | 30 | 30 |
DSG -B35XXX | 70 | 10 – 35 | 30 | 30 |
I/H Converter Module
DSM I/H Converter Module
Redundant I/H Converter, Redundant Current to Pressure Converter Assembly, Dual/Duplex Current to Pressure Converter (DX-CPC)

An I/H converter module consists of two I/H converters connected in parallel. An I/H converter changes a constant input pressure into a variable output pressure. A standard 4 – 20 mA signal specifies the output pressure. The major components of the I/H converter are a hydraulic unit and a
force-controlled electromagnet.
Every I/H converter has a monitoring circuit that detects a malfunction of the converter. In the event of converter malfunction, a hydraulic maximum selection circuitry ensures that the other I/H converter assumes control automatically. This makes it possible to remedy the cause of the malfunction during operation.
The Mean Time Between Failures (MTBF) for Voith pressure control modules is over 20,000 years. Your equipment runs for a very long period of time without unplanned downtime; availability is increased.
Technical data
Flow rate |
Up to 30 l/min [7.9 gpm] at 1 bar [14.5 psi] differential pressure |
Input pressure |
Up to 40 bar [580 psi] |
Maximum output pressure range | 0 – 10 bar [0 – 145 psi] |
MTBF (Mean Time Between Failures) | 20,000 years (calculated in accordance to MIL‑HDBK‑217 and Siemens SN 29500, actual MTBF evaluations from installed products show even higher values) |
Supply voltage |
24 VDC |
Current consumption | 1.0 A (3.0 A for t < 1 s) |
Input signal | 4 – 20 mA |
Fail-safe operation |
Fail-safe position through output pressure |
Redundancy | Hot redundancy |
Ambient temperature | -20 to +80°C [-4 to +176°F] (standard version, not rated for use in potentially explosive areas) |
Explosion proof rating (optional) |
|
Protection class | IP 65 |
Safety integrity level | SIL 2 |
Advantages and benefits
- Thanks to the redundancy provided by the two I/H converters, the Mean Time Between Failures (MTBF) for the pressure control module is over 20,000 years. Your equipment operates with maximum availability. Productivity increases and the costs associated with lost production remain low.
- It is possible to replace a faulty I/H converter during operation. You avoid unplanned downtime and their associated high costs.
- Voith pressure control modules are not sensitive to contaminated pilot oil. Turbine lubricating oil is suitable as the operating fluid. One oil supply system for both lubricating and pilot oil suffices. Maintenance is simple, which helps you lower operating costs.
- Very good control response, almost no hysteresis and a resolution better than 0.1% ensure very fast and accurate control. You benefit from having a stable process with high product quality.
- Connections are industry-standard. This means the I/H converter module can be integrated into your equipment easily. Standard adapter plates are available to allow the I/H converter module to interface with systems designed for Woodward CPC and CPC‑II converters. You reduce the costs for system integration.
- The output pressure range can be adjusted easily on-site by means of potentiometer. This allows you to adjust the output pressure for the application quickly and without any delays.
- For use in hazardous areas, we offer explosion proof pressure control modules with the required certificates.
Typical fields of use
- Operation of the control valve of
- steam turbines
- gas turbines
- compressors
- Retrofit of mechanic-hydraulic valve controls
- Upgrade of systems with Voith DSG I/H converters
- Upgrade of systems with partially or non-redundant
Woodward CPC or CPC‑II converters
Product inquiry
Technical Information
Functionality

The pressure control module employs a two-channel design. A redundant control system provides the two input signals w1 and w2 for the two
I/H converters. The hydraulic output pressure pA1 or pA2 from each of the I/H converters is proportional to the applied 4 – 20 mA input signal.
The two pressures are connected to a hydraulic maximum selection circuitry, which then selects the higher pressure. Lowering the setpoint from the control system gradually during operation allows additional built-in pressure sensors to provide continuous monitoring of the hydraulic function. This pressure variation makes it possible to diagnose each of the subsystems while operating. Each I/H converter has an electronic monitoring circuit that detects a malfunction of the converter. If one I/H converter fails, a hydraulic maximum selection circuitry ensures that the other converter assumes control automatically.
The output pressure from the correctly operating I/H converter is used. This makes it possible to remedy the cause of the malfunction during operation.
Control schematic

Selection table
Typ | Maximum input pressure [bar] |
Output pressure range [bar] |
Flow rate [l/min] at 1 bar differential pressure |
|
P > A | A > T | |||
DSM -B05XXX |
40 |
0 – 5 | 30 | 30 |
DSM -B10XXX | 40 | 0 – 10 | 30 | 30 |
Way Valve
WSR Way Valve
E/H Converter, Servo Directional Control Valve, Servo-Proportional Valve

Voith electro-hydraulic way valves are servo directional control valves. They have integrated position control and provide direct control of hydraulic positioning cylinders. The positioning cylinders operate a valve that controls the mass flow needed to drive machinery. Voith way valves ensure very precise and high dynamic control of the mass flow.
Working in conjunction with a hydraulic cylinder, the way valve converts a constant input pressure into a variable stroke. A standard 4 – 20 mA signal specifies the stroke of the positioning cylinder. The major components of a way valve are a 3/3 way hydraulic unit for single-acting positioning cylinders or a 4/3 way hydraulic unit for double-acting positioning cylinders and a force-controlled electromagnet with integrated position control. An additional pilot valve is not needed with the Voith electrohydraulic way valve.
The way valve features a simple, compact design. This ensures consistent, reliable operation. The Mean Time Between Failures (MTBF) for Voith way valves is over 180 years. Your equipment runs for a very long period of time without unplanned downtime. Availability is increased.
The way valve is available in two redundant designs:
- T-WSR Tandem Way Valve (Dual Coil Way Valve) with redundant control magnets (warm redundancy)
- WSM Way Valve Module (hot redundancy)
Technical data
Flow rate | Up to 600 l/min [158 gpm] at 1 bar [14.5 psi] differential pressure |
Input pressure | Up to 200 bar [2,900 psi] |
MTBF (Mean Time Between Failures) | 180 years (calculated in accordance to MIL‑HDBK‑217 and Siemens SN 29500, actual MTBF evaluations from installed products show even higher values) |
Supply voltage |
24 VDC |
Current consumption |
1.0 A (3.0 A for t < 1 s) |
Input signal | 4 – 20 mA |
Communication (optional) |
|
Fail-safe operation | Internal return spring |
Ambient temperature | -20 to +80°C [-4 to +176°F] (standard version, not rated for use in potentially explosive areas) |
Explosion proof rating (optional) |
|
Protection class | IP 65 |
Safety integrity level | SIL 2 |
Advantages and benefits
- The Mean Time Between Failures (MTBF) is over 180 years. Your equipment operates very reliably. Productivity increases and the costs associated with lost production remain low.
- Voith way valves are not sensitive to contaminated pilot oil. Turbine lubricating oil is suitable as the operating fluid. One oil supply system for both lubricating and pilot oil suffices. Maintenance is simple, which helps you lower operating costs.
- During load rejection, the way valve shifts the control valve to the partial-load position very rapidly (approx. 300 ms). When a shutdown command is received, the way valve shifts the control valve to the safe position (open or closed) very rapidly (approx. 300 ms). This ensures high availability of your equipment.
- The way valve incorporates fast and exact position control. Very good control response, almost no hysteresis and a resolution better than 0.1% ensure very fast and accurate control. You benefit from having a stable process with high product quality.
- Connections are industry-standard. The way valve mounts to your equipment easily. This reduces the costs for integration.
- The stroke and control gain can be adjusted easily on-site by means of potentiometer. This allows you to adjust both quantities to the application quickly and without any delays.
- For use in hazardous areas, we offer explosion proof way valves with the required certificates.
Typical fields of use
- Operation of the control valve of
- steam turbines
- gas turbines
- compressors
- Retrofit of mechanic-hydraulic valve controls
- Upgrade of systems with Voith DSG I/H converters
- Upgrade of systems with Woodward CPC or CPC-II converters
Product inquiry
Technical Information
Design

Functionality

On the basis of the control deviation (setpoint w – actual value x) and the control gain settings KPU and KPD, a command variable UMAG is generated for the magnetic force's controller. The magnetic force FMag is determined indirectly by measuring the magnetic flux with the aid of UHall and sent to the controller.
FMag acts on the control piston in the hydraulic pilot valve via the plunger. The piston is forced against the control spring until the stroke-dependent spring force FF equals FMag. This provides a volume flow that varies in direction and magnitude, and produces stroke s in an externally mounted hydraulic cylinder.
A position sensor determines the actual position and feeds an electrical signal back to the position controller. This ensures closed-loop control of hydraulic cylinder positioning.
Control schematic

Selection table
Selection table for 3/3 way valves
Type | Maximum input pressure [bar] |
Flow rate [l/min] at 1 bar differential pressure |
|
P > A | A > T | ||
WSR-C25XXX | 200 | 17 | 62 |
WSR-C45XXX | up to 40 | 22 | 75 |
WSR-C60XXX | up to 40 | 35 | 150 |
WSR-E60XXX | up to 40 | 30 | 350 |
WSR-E80XXX | up to 40 | 50 | 600 |
WSR-K120XXX | 25 | 600 | 600 |
Selection table for 4/3 way valves
Type | Maximum input pressure [bar] |
Flow rate [l/min] at 1 bar differential pressure |
|
P > A/B | A/B > T | ||
WSR-D16XXX | up to 160 | 14 | 14 |
WSR-D24XXX | 40 | 40 | 40 |
WSR-D45XXX | up to 40 | 80 | 80 |
WSR-D60XXX | 40 | 130 | 130 |
WSR-D80XXX | 25 | 180 | 180 |
WSR-K120XXX | 25 | 600 | 600 |
Tandem Way Valve
T-WSR Tandem Way Valve
Servo Directional Control Valve with Redundant Control Magnet Unit (Dual Coil System)

A tandem way valve consists of two electromagnets with integrated position control connected in series and a 3/3 way hydraulic unit for single-acting positioning cylinders or a 4/3 way hydraulic unit for double acting positioning cylinders. Working in conjunction with a hydraulic cylinder, the way valve converts a constant input pressure into a variable stroke.
A standard 4 – 20 mA signal specifies the stroke of the positioning cylinder. An additional pilot valve is no longer needed with the Voith electrohydraulic tandem way valve.
In the event of a malfunction, control magnet 1 switches off automatically and control magnet 2 switches on. The switching logic is located in the external control system and monitors the control magnets.
The Mean Time Between Failures (MTBF) for Voith tandem way valves is over 360 years. Your equipment runs for a very long period of time without unplanned downtime; productivity is increased.
Technical data
Flow rate |
Up to 600 l/min [158 gpm] at 1 bar [14.5 psi] differential pressure |
Input pressure | Up to 200 bar |
MTBF (Mean Time Between Failures) | 360 years (calculated in accordance to MIL‑HDBK‑217 and Siemens SN 29500, actual MTBF evaluations from installed products show even higher values) |
Supply voltage |
24 VDC |
Current consumption | 1.0 A (3.0 A for t < 1 s) |
Input signal | 4 – 20 mA |
Communication (optional) |
|
Fail-safe operation | Internal return spring |
Redundancy | 2 Control magnets (warm redundancy) |
Ambient temperature | -20 to +80°C [-4 to +176°F] (standard version, not rated for use in potentially explosive areas) |
Explosion proof rating (optional) |
|
Protection class |
IP 65 |
Safety integrity level | SIL 2 (on request) |
Advantages and benefits
- Thanks to the redundancy provided by the two way valve magnets, the Mean Time Between Failures (MTBF) for the tandem way valve is over 360 years. Your equipment operates with maximum availability. Productivity increases and the costs associated with lost production remain low.
- Voith tandem way valves are not sensitive to contaminated pilot oil. Turbine lubricating oil is suitable as the operating fluid. A common oil supply system for both lubricating and pilot oil suffices. Maintenance is simple, which helps you lower operating costs.
- During load rejection, the way valve shifts the control valve to the partial-load position very rapidly (approx. 300 ms). When a shutdown command is received, the way valve shifts the control valve to the safe position (open or closed) very rapidly (approx. 300 ms). This ensures high availability of your equipment.
- The way valve incorporates fast and exact position control. Very good control response, almost no hysteresis and a resolution better than 0.1% ensure very fast and accurate control. You benefit from having a stable process with high product quality.
- The tandem way valve mounts to your equipment easily. This reduces the costs for integration.
- The stroke and positioning function can be adjusted easily on-site by means of potentiometers.
This allows you to adjust the stroke to the application quickly and without any delays. - For use in hazardous areas, we offer explosion proof tandem way valves with the required certificates.
Typical fields of use
- Operation of the control valve of
- steam turbines
- gas turbines
- compressors
- Retrofit of mechanic-hydraulic valve controls
- Upgrade of systems with Voith DSG I/H converters or
WSR way valves - Upgrade of systems with partially or
non-redundant Woodward CPC or CPC-II converters
Product inquiry
Technical Information
Functionality

A redundant control system provides the two setpoints w1 and w2 in the form of standard 4 – 20 mA signals for the two control magnets. A separate position sensor (x1in and x2in) is connected to each control magnet. The armature of control magnet 1 acts through control magnet 2 to move the control piston of the hydraulic pilot valve. If control magnet 1 is energized, control magnet 2 is de-energized, but powered. In the event of a malfunction, control magnet 1 is
de-energized and control magnet 2 is energized via setpoint w2 with a brief delay ("warm redundancy"). The switching logic is located in the external control system and monitors the control magnets (position sensor displays x1out and x2out). The switching logic also generates the switching signals.
Control schematic
Control schematic for a 3/3 T-WSR Tandem way valve

Control schematic for a 4/3 T-WSR Tandem way valve

Way Valve Module
WSM Way Valve Module

Redundant Way Valve, Redundant Servo Directional Control Valve
Voith way valve modules are redundant servo directional control valves. They have integrated position controls and provide direct control of hydraulic positioning cylinders in processes requiring high availability. The positioning cylinders operate a valve that controls the mass flow needed to drive machinery. Voith way valves ensure very precise and highly dynamic control of the mass flow.
A way valve module consists of two way valves connected in parallel. Working in conjunction with a hydraulic cylinder, the way valve converts a constant input pressure into a variable stroke. A standard 4 – 20 mA signal specifies the stroke of the positioning cylinder. The major components of the way valves are a
3/3 way hydraulic unit for single-acting positioning cylinders and a force-controlled electromagnet with integrated position control.
An additional pilot valve is not needed with the Voith electrohydraulic way valve module.
Every way valve has a monitoring circuit that detects malfunction of a way valve. In the event of way valve malfunction, a hydraulic maximum selection circuitry ensures that the other way valve assumes control. This makes it possible to remedy the cause of the malfunction during operation.
The Mean Time Between Failures (MTBF) for Voith way valve modules is over 8,800 years. Your equipment runs for a very long period of time without unplanned downtime; availability is increased.
Technical data
Flow rate | Up to 700 l/min [182 gpm] at 4 bar [58 psi] differential pressure |
Input pressure | Up to 40 bar [580 psi] |
MTBF (Mean Time Between Failures) | 8,800 years (calculated in accordance to MIL‑HDBK‑217, Siemens SN 29500 and taking into account diagnostic capability and reparability during operation at the actual redundancy) |
Supply voltage | 24 VDC |
Current consumption | 2.0 A (6.0 A for t < 1 s) |
Input signal | 4 – 20 mA |
Communication (optional) |
|
Fail-safe operation | Internal return spring in each way valve |
Redundancy | Hot redundancy |
Ambient temperature | -20 to +80°C [-4 to +176°F] (standard version, not rated for use in potentially explosive areas) |
Explosion proof rating (optional) |
|
Protection class | IP 65 |
Safety integrity level | SIL 2 (on request) |
Advantages and benefits
- Thanks to the redundancy provided by two way valves, the Mean Time Between Failures (MTBF) for the way valve module is over 8,800 years. Your equipment operates with maximum availability. Productivity increases and the costs associated with lost production remain low.
- It is possible to replace a faulty way valve during operation. You avoid unplanned downtime and their associated high costs.
- Voith way valve modules are not sensitive to contaminated pilot oil. Turbine lubricating oil is suitable as the operating fluid. One oil supply system for both lubricating and pilot oil suffices. Maintenance is simple, which helps you lower operating costs.
- During load rejection, the way valve shifts the control valve to the partial-load position very rapidly (approx. 300 ms). When a shutdown command is received, the way valve shifts the control valve to the safe position (open or closed) very rapidly (approx. 300 ms). This ensures high availability of your equipment.
- The way valve incorporates fast and exact position control. Very good control response, almost no hysteresis and a resolution better than 0.1% ensure very fast and accurate control. You benefit from having a stable process with high product quality.
- Connections are industry-standard. The way valve module mounts to your equipment easily.
This reduces the costs for integration. - The stroke and positioning speed can be adjusted easily on-site by means of a potentiometers.
This allows you to adjust the stroke to the application quickly and without any delays. - For use in hazardous areas, we offer explosion proof way valve modules with the required certificates.
Typical fields of use
- Operation of the control valve of
- steam turbines
- gas turbines
- compressors
- Retrofit of mechanic-hydraulic valve controls
- Upgrade of systems with Voith DSG I/H converters,
WSR way valves or T‑WSR tandem way valves - Upgrade of systems with Woodward current-to-pressure converters CPC, CPC-II or CPC-DX
Product inquiry
Technical Information
Control schematic

Functionality
The way valve module employs a two-channel design. A redundant control system provides the two setpoints w1 and w2 in the form of a standard 4 – 20 mA signal for the two way valves. The control gain setting is the same for both valves. The output pressures pA1 and pA2 or the corresponding volume flows are directed to the "Max. Module", the A port of which is connected to the single-acting cylinder. If one of the two way valves fails, the associated force exerted by the magnetic force FMag and the output pressure drop to zero. The resulting connection of the A port in the way valve to the tank return line T causes the ball in the "Max. Module" to block the output of the failed way valve automatically. The pressure gauge and pressure transmitter on the associated way valve module display 0 bar. The functional way valve assumes control automatically and keeps the equipment operating. It is possible to replace the faulty way valve during operation.
Control Servo Motor
SMR Control Servo Motor

Linear Electro-hydraulic Actuator for Steam Turbines, Gas Turbines and other Applications
The control servo motor is an intelligent and compact functional unit consisting of a hydraulic cylinder, control magnet with integral position control, hydraulic pilot valve and position sensor. When a servo motor is used, no additional components such as pilot valve and hydraulic cylinder, for instance, are needed to operate the control valves.
A standard 4 – 20 mA signal specifies the position of the piston rod. The control servo motors feature a simple and compact design. This ensures consistent and reliable operation. The Mean Time Between Failures (MTBF) for Voith control servo motors is over 103 years. Your equipment runs for a very long period of time without unplanned downtime; availability is increased. The control servo motor is also available in a redundant design (position feedback system and way valve control).
Technical data
Full-stroke closing time (Trip) | < 0.3 s |
Maximum pressure | Up to 200 bar [2,900 psi] |
Effective forces | Up to 500 kN [112,000 lbf] |
MTBF (Mean Time Between Failures) | 103 years (calculated in accordance to MIL‑HDBK‑217 and Siemens SN 29500, actual MTBF evaluations from installed products show even higher values) |
Supply voltage | 24 VDC |
Current consumption | 1.0 A (3.0 A for t < 1 s) |
Input signal | 4 – 20 mA |
Communication (optional) |
|
Fail-safe operation | Internal return spring in way valve and additionally in hydraulic cylinder on single acting designs |
Redundancy (optional) |
Position feedback system and way valve control magnets |
Ambient temperature | -20 to +80°C [-4 to +176°F] (standard version, not rated for use in potentially explosive areas) |
Explosion proof rating (optional) |
|
Protection class |
IP 65 |
Safety integrity level | SIL 2 |
Advantages and benefits
- The Mean Time Between Failures (MTBF) is over 103 years. Your equipment operates very reliably. Productivity increases and the costs associated with lost production remain low.
- Voith control servo motors are not sensitive to contaminated pilot oil. Turbine lubricating oil is suitable as the operating fluid. One oil supply system for both lubricating and pilot oil suffices. Maintenance is simple, which helps you lower operating costs.
- During load rejection, for instance, the control servo motor reaches the safe position in less than
300 ms. This ensures that your equipment operates with high reliability and availability. After a malfunction, the equipment is ready to operate again very quickly. - The high dynamic behavior (response time in the closing direction: < 200 ms) and almost no hysteresis (< 0.01% of maximum stroke) ensure fast, accurate control. You benefit from having a stable process with high product quality.
- The integral electronic position control in the Voith servo motor eliminates the need for
time-consuming tuning of controller, position sensor and actuator during test runs and commissioning.
This reduces the time required for commissioning and saves money. - We design our servo motors to be compatible with existing machine designs. This gives you design flexibility. Engineering costs are lowered and the time you need for design is shortened.
- For use in hazardous areas, we offer explosion-proof control servo motors with the required certificates. The interface to the machine control system is the same for conventional and
explosion-proof versions.
Typical fields of use
- Actuation of the control valve of
- steam turbines
- gas turbines
- compressors
- Retrofit of mechanic-hydraulic valve controls
- Retrofit of hydraulic, electro-mechanical and
pneumatic linear actuators - Upgrade of systems with Voith I/H converters DSG
or way valves WSR - Upgrade of systems with Woodward actuators:
- Varistroke Linear Electro-hydraulic Actuator
- EHPC Electrohydraulic Power Cylinder
- EHPS Electrohydraulic Power Servo
- PGPL Hydraulic Powered Electric Actuator
- EG-3P Hydraulic Amplifier
- TM‑25LP or TM‑200LP Linear Proportional Actuators
- CPC or CPC‑II Current to Pressure Converters
Product inquiry
Technical Information
Functionality

The servo motor is controlled by a standard 4 – 20 mA signal from the control system. The piston rod position is proportional to this standard signal w. In the position control loop, the setpoint w is compared with the actual position x of the piston rod measured by the position sensor and any deviation causes the controller to adjust the magnetic force FMag. This force (FMag) shifts the control piston in the way valve against a spring, causing a change in the direction and magnitude of the volume flow to the actuating chamber of the cylinder. In conjunction with the spring pack, the hydraulic force resulting from the volume flow changes the position s of the piston rod. The piston rod moves at a speed determined by the volume flow into or out of the actuator.
Control schematic

Selection table

SelCon Linear Actuator
SelCon Linear Actuator for Actuating Valve Control Equipment
SelCon Self-contained Electrohydraulic Linear Actuator with Fail-safe Function, Linear Servo Hydraulic Valve Actuator, Linear Actuator for Governor Valve Control with Trip Function, e.g. for Gas Turbine or Steam Turbine Applications

This innovative actuator is a reliable plug-and-play solution with fail-safe function. The SelCon is a compact design, provides high force density and is a true alternative to conventional actuators. With the SelCon you don't need an additional hydraulic power pack with an oil tank, control block and pipework. The amount of hydraulic fluid in the system is minimal. On the outside the SelCon only has electrical and mechanical interfaces. Handling and system integration is extremely simple. No knowledge of hydraulics is required for installation and commissioning.
Our engineers selected proven components when designing the SelCon. The core components consist of a servo motor, a Voith internal gear pump, a cylinder with an internal return spring and a displacement transducer.
A control unit with implemented application software acts as the brain of the system. The actuator exhibits a high degree of operational safety and reliability; the estimated mean time between failures (MTBF) is 35 years.
The SelCon is optionally available as a trip actuator with no control function (switch actuator).
Technical data
Closing time for full stroke (trip) | typically < 0.3 s |
Motion time for full stroke (controlled) | typically 0.5 s |
Effective forces | up to 500 kN [112,000 lbf] |
MTBF (Mean Time Between Failures) | 35 years (estimated, theoretical value |
Supply voltage for the SelCon electronics | 24 VDC |
Current consumption for the SelCon electronics | 5 A |
Supply voltage for the control unit | 3 x 207 – 528 VAC, 50/60 Hz |
Current consumption for the control unit | 17 A, max. 32 A when balanced < 1 A |
Input signal |
4 – 20 mA |
Communication (optional): |
|
Fail-safe function | Internal return spring |
Ambient temperature | 0 to +60°C (standard version, not rated for use in potentially explosive areas) |
Explosion protection (optional) |
|
Protection class | IP 65 |
Safety integrity level |
SIL 2 (upon request) |
Optional |
Design as a trip actuator with no control function (switch actuator) |
Typical applications
- Actuation of the control valve in
- steam turbines
- gas turbines
- compressors
- Retrofit of mechanical-hydraulic valve controls
- Retrofit of hydraulic, electromechanical and pneumatic actuators
- Linear actuator for process valves with fail-safe function
- Upgrade of systems with the Voith DSG I/H converters, WSR way valves and SMR control servo motors
- Upgrade of systems with Woodward actuators:
- Varistroke linear, electrohydraulic actuator
- EHPC Electrohydraulic Power Cylinder
- EHPS Electrohydraulic Power Servo
- PGPL Hydraulic Powered Electric Actuator
- EG 3P Hydraulic Amplifier
- TM 25LP or TM 200LP Linear Proportional Actuators
- CPC or CPC II Current to Pressure Converters
Advantages and benefits
Features |
Advantages |
Benefits |
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Technical information
Design

Function

The SelCon has two functions, namely providing a control function and a safety function (trip). In control mode, the SelCon regulates the position of the piston rod using the setpoint signal w from the control system.
The piston rod is connected to the control valve that controls the mass flow and changes its opening cross-section. If the setpoint signal is switched off, the trip solenoid valve opens. The piston rod is moved to its safety position by the energy stored in the return spring. This is carried out in an uncontrolled manner and at high speed. An auxiliary electrical power supply is required for operating the SelCon. All electrical components are protected against environmental influences. The electronic position detection system is integrated in the actuator. The control loop parameters for position control and the parameters for scaling the piston rod position are set using the application software implemented in the control unit.
Control schematic

EMA Electromechanical Linear Actuator
EMA Electromechanical Linear Actuator
EMA Electromechanical Valve Actuator with Fail-safe Function, Linear Servo Electric Valve Actuator, Linear Actuator for Governor Valve Control with Trip Function, e.g. for Gas Turbine or Steam Turbine Applications

It operates, for example, a valve that regulates the mass flow in a prime mover or a driven machine. Typical machines are gas turbines, steam turbines or compressors. The EMA provides you with highly dynamic and precise control of the mass flow.
This innovative linear actuator with fail-safe function has only electrical and mechanical interfaces. It is oil-free. This eliminates all costs for oil management that arise when operating a hydraulic linear actuator;
an 80% lower energy consumption reduces operating costs even more.
In addition, an oil-free actuator reduces the fire load of the entire system; insurance companies usually reward this with lower premiums. There is also nothing hindering the use of the actuator in places with strict environmental requirements.
With the EMA, you get an operationally safe and reliable plug-and-play solution having its own particular charm. The estimated mean time between failures (MTBF) of the Voith EMA is 35 years. As a result, your machine is very durable and you increase the productivity in your plant.
PS: Are you thinking about an oil-fee turbine? If you are, the EMA is certainly worth considering.
Technical data
Closing time for full stroke (trip) | Typically < 0.3 s |
Motion time for full stroke (controlled) | Typically 0.5 s |
Spring force | Up to 30 kN |
Actuating force |
Up to 40 kN |
MTBF (Mean Time Between Failures) | 35 years |
Supply voltage for the EMA electronics | 24 VDC |
Current consumption for the EMA electronics | 3.4 A |
Supply voltage for the control unit | 3 x 207 – 528 VAC, 50/60 Hz |
Current consumption for the control unit | 17 A, max. 32 A, when balanced < 1 A |
Input signal |
4 - 20 mA |
Communication (optional): |
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Fail Safe Operation | Piston rod retracted or extended, depending on the design |
Ambient temperature | -20 to +80°C (standard version, not rated for use in potentially explosive areas) |
Degree of protection |
IP 65 |
Safety integrity level | SIL 2 (optional) |
Optional | Design as a trip actuator with no control function (switch actuator) |
Typical applications
- Actuation of the control valve in
- steam turbines
- gas turbines
- compressors
- Retrofit of mechanical-hydraulic valve controls
- Retrofit of hydraulic, electromechanical and pneumatic actuators
- Linear actuator for process valves with fail-safe function
- Upgrading systems with the Voith DSG I/H converters,
WSR way valves and SMR control servo motors - Upgrading systems with Woodward actuators:
- PGPL Hydraulic Powered Electric Actuator
- TM 25LP or TM 200LP Linear Proportional Actuators
- CPC or CPC II Current to Pressure Converters
Advantages and benefits
Features | Advantages | Benefits |
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Technical information
Design

Function

Control schematic

How it works
The control system activates the EMA using a 4 – 20 mA standard signal. The stroke of the piston rod is proportional to this standard signal w. In the event of tripping, when the valve closes quickly, an electromagnetic coupling opens and decouples the motor mass. The return spring moves the piston rod into the safety position within 300 ms, either fully retracted or fully extended.
The EMA has two functions, namely providing a control mode and ensuring safety. In control mode, the EMA regulates the position of the piston rod using the setpoint w from the control system. The piston rod is connected to the control valve that controls the mass flow and changes its opening cross-section.
If the setpoint signal is switched off (< 3.2 mA), the electromagnetic coupling opens. The piston rod is moved to the safety position by the energy stored in the return spring. This is carried out in an uncontrolled manner and at high speed. The piston rod is held in the safety position. Additionally, the power section of the VFD (variable frequency drive) in the control unit is switched off. This ensures that the piston rod moves to its safety position even in the event of an electromagnetic coupling malfunction. An auxiliary electrical power supply is required for operating the EMA. All electrical components are protected against environmental influences. Electrical position detection is integrated in the drive. The controllers with circuitry for setpoint limitation and minimum value switch-off are integrated into the control unit. The control loop parameters and the parameters for scaling the piston rod position are set on the control unit using the relevant software.
TripCon Trip Block
TripCon Trip Block
Electro‐hydraulic Trip Block Assembly for Quick Trip, Electro-hydraulic Safety Control Unit, Fast‑Acting Control System for Actuators, Turbine Trip System
All variants of the trip block have a triple-redundant design with a
2oo3 selection (2 out of 3 voting). This means that turbine trips do not take place until at least two channels have been deactivated. An integrated
1oo1 partial stroke test enables a simple check of the function of the trip valve, even during operation. The partial stroke test is available with optional
2oo2 redundancy. An expansion module is also available, which allows the replacement of all solenoid valves during operation.
The TripCon is certified with the SIL 3 Safety Integrity Level. The Mean Time Between Failures (MTBF) for the Voith TripCon is over 100,000 years.
When developing the TripCon, our engineers paid particular attention to large discharge volumes and a dirt-resistant design. This allows you to achieve quick and safe turbine shutoff.
Technical data
Operating pressure | 2 to 180 bar [30 to 2,600 psi] |
Flow rate | Max. 320 l/min [85 gpm] at 5 bar [72 psi] differential pressure |
Trip function | 2oo3 (2-out-of-3) |
Valve partial stroke test |
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MTBF (Mean Time Between Failures) | 100,000 years (calculated in accordance to MIL‑HDBK‑217 and Siemens SN 29500, actual MTBF evaluations from installed products show even higher values) |
Ambient temperature |
-20 to +80°C [-4 to +176°F] |
Oil temperature | +10 to +70°C [50 to +158°F] |
Supply voltage | 24 VDC |
Current consumption | 0.8 A per solenoid |
Fail Safe Operation | Internal return spring on each solenoid valve |
Protection class |
IP 65 |
Explosion protection (optional) | ATEX/IECEx (II 2G IIC T4, Ta = -20°C to +60°C) |
Safety integrity level | SIL 3 |
Typical applications
- Safety control for steam turbines
- Safety control for gas turbines
- Control of process safety valves
- Retrofit of non-redundant trip systems
Advantages and benefits
Features | Advantages |
Benefits |
Modularity | ||
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Technical Information
Control schematic

TripCon – Superior
Feautures:
- Trip function: 2oo3
- Partial stroke test: 2oo2 during operation
- Replacement of the MV1 – MV5 solenoids during operation
- Replacement of the MV1 – MV5 solenoid valves during operation
- Optional Atex

TripCon – Advanced
Features:
- Trip function: 2oo3
- Partial stroke test: 1oo1 during operation
- Replacement of the MV1 – MV4 solenoids during operation
- Replacement of the MV1 – MV4 solenoid valves during operation
- Optional Atex

TripCon – Special
Features:
- Trip function: 2oo3
- Partial stroke test: 2oo2 during operation
- Replacement of the MV1 – MV5 solenoids during operation
- Replacement of the MV4 – MV5 solenoid valves during operation
- Optional Atex

TripCon – Basic
Features:
- Trip function: 2oo3
- Partial stroke test: 1oo1 during operation
- Replacement of the MV1 – MV4 solenoids during operation
- Replacement of the MV4 solenoid valve during operation
- Optional Atex

CTo Overspeed Protection
CTo Overspeed Protection

The CTo is a compact assembly and is intended for direct mounting to the actuator of the trip valve. This keeps signal paths short, making the unit immune to interference.
The CTo features a simple design. This ensures reliable operation. The Mean Time Between Failures (MTBF) for the Voith CTo is over 200 years.
Technical data
Flow rate (A to T) | 330 l/min [87gpm] at Δp = 4 bar [58 psi] |
Input pressure | Up to 25 bar [362 psi] |
MTBF (Mean Time Between Failures) | 200 years (calculated in accordance to MIL‑HDBK‑217 and Siemens SN 29500, actual MTBF evaluations from installed products show even higher values) |
Supply voltage | 24 VDC |
Current consumption |
0.5 A (2.5 A for t < 1 s) |
Fail-safe operation | Internal return spring |
Trigger frequency | 4,000 to 10,000 Hz, adjustable |
Ambient temperature | -20 to +80°C [-4 to +176°F] (standard version, not rated for use in potentially explosive areas) |
Explosion proof rating (optional) |
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Protection class |
IP 65 |
Safety integrity level |
SIL 2 |
Advantages and benefits
- The Mean Time Between Failures (MTBF) is over 200 years. Your equipment operates very reliably. Productivity increases and the costs associated with lost production remain low.
- The Voith CTo is not sensitive to contaminated pilot oil. Turbine lubricating oil is suitable as the operating fluid. One oil supply system for both lubricating and pilot oil suffices.
Maintenance is simple, which helps you lower operating costs. - The CTo features a simple design. Overspeed detection and tripping are decentralized.
This is a cost-effective solution – for both new equipment and when retrofit to existing equipment. - A partial stroke test ("Trip-Sim") permits testing of the trip valve during turbine operation.
This eliminates the need for additional hardware and keeps the system uncomplicated. - A separate speed feedback signal in the form of a 4 – 20 mA signal is available.
This makes installation of an additional speed measuring device unnecessary.
Typical fields of use
- Actuation of trip valves at
- steam turbines
- gas turbines
- compressors
Technical Information
Design

T Tank connection
P Oil supply connection (input)
1 Control magnet housing
2 Plunger
3 Electrical connection
4 Hydraulic section
5 Control piston
Functionality

The CTo consists of a 3/2 way hydraulic unit, a current-controlled electromagnet and the signal processing and control electronics. If there are no trip criteria, the control magnet generates the force FMag. This magnetic force presses the control piston of the hydraulic unit against a return spring. In this position, the hydraulic unit connects the pressure supply to the actuator of the trip valve, causing it to open. If there is a trip criterion (e.g. overspeed), the control magnet exciter current is interrupted immediately. The spring force FF exerted by the return spring shifts the control piston back to its original position, draining the actuator of the trip valve and causing it to close.
TurCon DTc Steam Turbine Controller
TurCon DTc Steam Turbine Controller
Turbine Governor for Steam Turbines with max. 6 Control Valves, Digital Control for Steam Turbines

It is pre-engineered with standard software. The software is based on proven, reliable algorithms for turbomachinery controls.
The parameters for control modes, such as speed control, demanding frequency control or complex extraction pressure control can be setup quickly and easily.
The controller consists of two robust assemblies of outstanding industrial quality. One is a touchscreen control panel with integrated CPU and the other a remote I/O unit. In addition, a PC or an optional 15" control panel can be easily connected via LAN. This is especially practical, for example, during commissioning or for remote monitoring. Communication with a higher-level control system (DCS) uses Ethernet with Modbus TCP or OPC.
The TurCon DTc is, in principle, a steam turbine controller for everyone.
If you are an OEM, you have a controller solution that economically fits in your overall system. If you are a contractor or modernizer, you can offer your clients an easy-to-use solution, whilst you benefit from our consulting expertise. If you are a steam turbine operator, you have a reliable product with proven control algorithms that ensures high process quality and productivity.
Technical data
Control panel | |
Operating voltage | 9.6 – 28.8 VDC |
Operating temperature | 0 °C to +55 °C |
Degree of protection |
IP 54 |
Dimensions (W x H x D) | 179 x 119 x 42 mm |
Assembly | Panel flush mounting |
HMI | 7" WVGA color TFT touchscreen with 800 x 480 pixels |
Remote I/O | |
Operating voltage | 20.4 – 28.8 VDC |
Operating temperature | 0 °C to +55 °C |
Degree of protection |
IP 20 |
Dimensions (W x H x D) | 390 x 130 x 52 mm |
Fastening | 35 mm DIN rails |
Inputs |
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Communication | |
Interface |
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RemoteView & Control |
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Configurable functions | |
Control modes for pumps, compressors, fans, etc. |
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Control modes for generators |
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Control options | Turbines with a maximum of 4 HP control valves and a maximum of 2 LP control valves |
Other |
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Typical applications
- Control of steam turbines that drive compressors, pumps, fans and other driven machines
- Control of steam turbines that drive generators
- Upgrade/retrofit of mechanical steam turbine controllers
- Upgrade/retrofit of analog steam turbine controllers, in particular
- Voith TurCon A
- Siemens / KKK SC800
- MAN / GHH Turbolog EKU
- Dresser Nadrowski / M+M / AEG
- Kanis / ABB CTn, CTp and CTf
- Upgrade of Woodward 505 and Woodward 505E steam turbine controllers
Advantages and benefits
Features | Advantages | Benefits |
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Technical Information
Control schematic

Maximum configuration

Panel images







TurCon DTc steam turbine controller in quality control



TurCon DTm Steam Turbine Controller
TurCon DTm Steam Turbine Controller
Single-Valve/Two-Valve Steam Turbine Governor, Steam Turbine Control

The TurCon DTm is a configurable digital controller which can be used on a wide range of steam turbines. It supports all established control modes –
from speed control and high-performance frequency control to complicated extraction pressure control. The controller is pre-engineered. This means that it is ready for operation after connecting and setting the parameters.
The controller is a modular assembly using standard hardware that is industry-proven. Standard software and a consistent, intuitive operating concept makes the TurCon DTm one of the most modern turbine controllers. As a user, you get a reliable plug-and-play solution featuring components that are optimally matched to each other. In addition, the TurCon DTm has an outstanding price/performance ratio.
Using Profibus DP the integration into a central control system is made easy. Besides this, the TurCon DTm, with its TFT LCD control panel, provides a
user-friendly and modern HMI with a touchscreen operator interface. The configuration and parameterization of the controller are performed via the control panel or optionally with a PC.
The TurCon DTm is available in three versions:
- Standard:
All hardware components wired in a cabinet incl. software. - OEM version:
CPU, memory card and LCD control panel, not wired incl. software. - Retrofitter version:
All hardware components without cabinet, not wired incl. software.
Technical data
Operating voltage | 21 – 28 VDC |
Ambient temperature | 0 to +40°C [+32 to +104°F] |
Dimensions | 500 x 500 x 210 mm |
HMI | 7" TFT LCD control panel with touchscreen operator interface |
Protection class | IP 65 |
Communication |
Optional:
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Configuration and parameterization |
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Inputs |
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Outputs |
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Driven machines |
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Control modes for pumps, compressors, fans etc. |
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Control modes for generators |
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Other |
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Typical Applications
- Control of steam turbines that drive compressors, pumps, fans and other driven machines
- Control of steam turbines that drive generators
- Upgrade/retrofit of mechanical steam turbine governors/controllers
- Upgrade/retrofit of analog steam turbine governors/controllers, especially
- Voith TurCon A
- Siemens / KKK SC800
- MAN / GHH Turbolog EKU
- Dresser Nadrowski / M+M / AEG Kanis / ABB CTn, CTp and CTf
- Upgrade of steam turbine controllers Woodward 505 and Woodward 505E
Advantages and benefits
Features | Advantages |
Benefits |
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Technical Information
Control schematic

Maximum configuration

Panel Images








Application example




How can we help you?
J.M. Voith SE & Co. KG | DSG
Actuators and Governors
Voithstraße 1 74564 Crailsheim Germany
t +49 7951 32-470
f +49 7951 32-605
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