Features
Emergency operation via handwheel
- Emergency operation via handwheel is possible without declutching the motor
- Therefore manual operation is possible even when the valve and the actuator are mechanically temporary seized
- Because of the fact, that a switch over mechanism is not required, motorized operation of handwheel is possible, via a powertool adaptor
Sketch: Operation via Handwheel
EMG enclosed motors
DREHMO valve actuators are supplied as a standard with EMG enclosed 3 phase AC squirrel cage motors. The motor housing is totally enclosed. This construction guarantees the greatest possible protection against humidity and dust ingress and is therefore suitable for extreme ambient conditions.
Type of duty: On-off duty S2-10/15 min.; modulating duty S4
Insulation Class F
IEC motors and special motors
DREHMO actuators can be supplied with standard motors instead of EMG enclosed motors.
Thermal protection for the motor
Three thermal switches connected in series are mounted in each of the motor windings individually. In case of the motor temperatures exceeding 155°C the control circuit is interrupted. The contact to open unit is integrated within the Matic C control unit.
Ambient temperatures
The permitted ambient temperature range for the standard version of the DREHMO-Matic C actuators is from -25 °C to +70 °C; for the explosion proof version and actuators for modulating duty from -25 °C to +60 °C.
Enclosure type
According to IEC 144, EN 60529 and DIN VDE 470. DREHMO actuators with EMG-enclosed motor are supplied as standard with enclosure type IP 67. IP 68 is available on request.
Conformity to CE rules
DREHMO actuators comply with the CE rules of conformity according to the EG directive for machines 89/392/EWG, the EG directive for low voltage 73/23/EWG and the directive for EMV 89/336/EWG.
Painting, protection against corrosion
Standard color: RAL 5015, blue
Corrosion protection K 3: For operation in occasional agressive atmospheres
Corrosion protection K 4: For operation in permanent corrosive atmospheres
Corrosion protection K 5: For operation in extremely agressive atmospheres, for example inside of cooling towers
Electrical connection
Electrical connection is accomplished by means of a compact plug connector which connects the control and signal wires as well as the power supply (two plugs within one housing). Method of connection is screw terminals for control plug and cage clamp terminals for power supply.
Output drives
Multi turn
Types and sizes of mounting flanges according to DIN ISO 5210 or DIN 3210. Hollow shaft for rising spindles.
Output-drive types: Stem nut, plug bush, bore with keyway, claw coupling, shaft extension. Special output-drives on request.
Part turn
Types and sizes of mounting flanges according to DIN ISO 5211 or DIN 3337.
Output-drive types: Bore with keyway, dihedron, square bore.
Thrust
according to DIN 3358
Combi Sensor
For continuous measuring of position and torque the combi sensor is used. The 4..20 mA signal and also the limit positions are programmed by means of learn function.
A second measuring input is used to make an analogue recording of the torque reached, which is then compared and evaluated with settable switch-off values in the control unit.
Limit switches
Position related switch-off is necessary when certain types of valves must not be seated in their mechanical end positions via torque or thrust. The operation of the limit switches is done by an adjustable counter gear unit. The limit-information is detected and analysed directly within the Matic C control unit.
Position sensor
For continous detection of the current valve position DREHMO-Matic C actuators can be supplied with an electronic travel sensor as an alternative to the conventional counter gear unit. This travel sensor is able to deliver limit signals and intermediate position signals as well as an analogue 4-20 mA position signalThe limit position information is stored electronically, it will not be lost in case of power failure.
Torque switches
To protect the operated valve against mechanically overloads, torque switches switch the DREHMO off actuator when a certain, pre-setted torque value is reached. For limit related switch-off, the torque switches are an additional safety device to protect the valve from mechanical overload. The torque switches are directly integrated in the Matic C control unit.
Torque sensor
The torque at the output drive is measured by an analogue torque sensor. Within the Matic C control unit the measured value is compared with the setted switch-off values. The current torque value is measured and analysed continously during operatin of the DREHMO (analogue measurement); the lower detection bound is limited by the calibrated pre-load of the torque springs (12) only.
Reduction gear, standard
Within the part turn actuator range DREHMO-Matic C, model DPM C 30 - DPM C 119 a reduction gear with a cam switch unit for operating of the limit switches replaces the counter gear of the multi-turn actuator range. In addition, this reduction gear drives a mechanical position inidcator and / or an electronic position transducer.
Reduction gear, optional
Optional, the reduction gear can be fitted to any other type in addition to the countergear in order to operate a mechanical dial position indicator and / or an electronic position transducer.
