Dr Kesorn Pechrach Weaver: Piezoelectrics in Circuit Breakers: Contact speed setup

Dr Kesorn Pechrach Weaver: Piezoelectrics in Circuit Breakers: Contact speed setup: 5.1 Contact speed setup The opening contact mechanism was modified to reduce contact speed from 10 m/s down to 1 m/s. There are tw...

Contact speed setup

5.1 Contact speed setup

The opening contact mechanism was modified to reduce contact speed from 10 m/s down to 1 m/s. There are two important parts in this system. The first part is the instrument to measure the speed of contact and the second part is the instrument to control the speed. The instrumentation used to measure the contact velocity is the displacement sensor which is connected to the solenoid. The method used to control the contact velocity is to control the supply voltage to the motor of the solenoid.

5.1.1 Displacement sensors

The pivot mechanism moves in a curve with a very high speed, it is very difficult to measure speed directly from this system. It is not very difficult to measure the velocity of the solenoid movement and calculate the speed of the pivot mechanism and contact. The displacement transducer uses a filter pattern together with intensity sensitive photo sensors. Details of the displacement transducer control circuit and differential op-amp circuits are shown in Figure 5.1 –5.2. 

Figure 5.1:  Control diagram of displacement transducer

Figure 5.2: Detail of the differential circuit for output signal of displacement transducer