Electro-mechanical linear actuator for the adjustment of valves or valve groups
Application
Activation of control valves in turbo machinery, such as gas turbines, steam turbines and compressors.
Design and function
A "Voith EMA" is the intelligent and compact electro-mechanic combination of electro-motor, magnetic clutch, belt gear box, linear unit, restoring spring and stroke pick up. An frequency converter is used as power element.
The integrated position controller realizes on demand of feeded set value 4-20 mA linear stem movement. In case of trip (fast closing of valve) magnetic clutch opens and decouples mass of electro motor. Thus restoring spring can move stem within shortest time into its safety position (full retracted resp. extended).
Advantages - No hydraulic oil for power required
- Fire hazard by oil leakage on hot turbine parts excluded (attractiveinsurancerate)
- Expensive piping an oil conditioning becomes not applicable
- Comparable performance data as known on our electro-hydr-acuators (forces, dynamik, accuracy, fail safe)
- Modular design: by changing of single components like frequency converter, gear box and linear unit, different sizes for different application can be easliy completed.
- Compatible to our electro hydraulic servomotors1
| Technical data | Size 1 | Size 2 | Size 3 | | Rated stroke [mm] | 85 | 130 | 210 | | Actuating force [kN] max. (static) | 5 | 11 | 30 | | Spring force [kN] min. | 1,5 | 2 | 6,7 | | t_Trip 100% [s] | 0,2 | 0,2 | 0,2 | | T_Control 100% [s] | 0,7 | 0,7 | 0,7 | |
