Pressure Switches and Power Transformers

What pressure switch are you talking about?

Do you mean the PRD - pressure relief device?

yes i mean pressure relief device (PRD)

Do you mean the Bucholtz Relay? See link:

http://en.wikipedia.org/wiki/Bucholtz_relay

Rok

dgapare,

If you are referencing to the "sudden-pressure" switch on the transformer.

It is designed to:

1. Sense the rapid (sudden) change of internal gas pressure caused by transformer winding & connection electrical faults inside the transformer can/housing.
2. Isolate (turn off) the transformer primary power to mitigate equipment damage.
3. Generate an alarm to call attention to the problem.

Generally these are "diaphram type" units with an adjustable orfice used to calibrate the DELTA-P applicable to the transformer size. The actual operation of the device very much mimic a pneumatic time delay relay mechanism.

surprise

No difference between Pressure switch and PRD

what you want to know about ? PS or PRD ?

I understand it would be ideal to cut off the primary supply to the transformer if the sudden pressure switch activated as describe in your item 2. What if the transformer protection is a fuseible disconnect switch that does not have shunt trip features as a breaker? When the pressure relief device activated and after it releases the gas pressure, will the transformer remain on line or will the primary fuses blow due to the electrical faults caused by the sudden pressure? Or is it good enough to send the alarm signal and have some one goes to check and/or isolate the primary switch after notice the sudden gas pressure issue?