How does an unloader work in an air compressor?

A way of safety that to stop the compressor, a spring acts on a lever makes a short circuit and turn the compressor off.

a specific valve used for this function because some time we need to start the compressor without air compress.its most important for chekout the rmp and voltage.ampere to checkout.

An air compressor unloader valve is found in the reciprocating piston compressor and its used to blow off pressure inside the discharge pipe when the compressor stops.
It works by blowing off the pressure contained its pipe immediately the compressor stops.
The output is connected through a pipe which links it to the air receiver.

when Compressor get stop so some gas remains in different stages and its can make overload the compressor.when compressor get start.the unloader works as relife valve to make the compressor easier in starting.

the unoader incloud a piston an spring under it and air pipe cotrol when need to air pistone move and open the gate and the compressor make air