Thyristor Governor TR701

Basically the speed control circuit consists of the d.c. motor and the thyristor governor. The mains supplies the thyristor governor with 230 V. A variable voltage is applied to the armature of the shunt-wound electric d.c. motor or the permanent magnet motor in order to get the speed to the set governor value. The advantage of this armature voltage control is the constant torque at any speed - a condition which is required by metering pumps.

The desired value is set at the governor by means of the potentiometer or externally as voltage or loadindependent direct current using the 0...20 mA standard signal. The speed is repeated to the governor as tachometer voltage or as I X R compensation. The largest control range (more than 1:30) is possible with tachometer repeating signaling (accuracy approx. 1%). For diaphragm metering pumps and piston metering pumps, the control range of which is only used by approx. 1:20, I X R compensation is sufficient, i.e.: the tachometer is not required (accuracy approx. 3%).