Instrumentation Interview Question:

What is force balance principle? State some of its' advantages?

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Force balance principle: A controller which generates an output signal by opposing torque. The input force is applied on the input bellows which moves the beam. This crackles nozzle back pressure. The nozzle back pressure is sensed by the balancing bellows which brings the beam to balance. The baffle movement is very less about 0.002 for full scale output.

Advantages:
a. Moving parts are fewer.
b. Baffle movement is negligible
c. Frictional losses are less
Submitted by: Administrator