Any Demerits In Cut In and Cut Off of 2 Compressors Together?

Well, starting two things at once needs a heavier power supply than starting them in sequence. Has this issue been checked?

Type of compressor? Frequency of stopping and starting? By cut in and cut out do we mean complete shut down or unloading?

I am making some assumptions as to your use of the term "compressors": That they are air compressors, running at a normal pressure of 100 psi, +/-. They are also piston compressors that are kicked in and out with unloading valves while continuing to run and are not large sized equipment, say, over 150 hp.

The normal way to cycle compressors is to cut them in and out one by one. You can set them up so that as the pressure drops, one cuts in, and if the pressure continues to fall, the second machine cuts in. As the pressure rises, one machine cuts out and if pressure continues to rise, then the second machine cuts out. However, there should be no significant penalties in operating them in tandem, unless, as suggested by others, the power system is marginal. Stopping and starting the compressors by turning off the electric motor should not be done unless you can be assured they will be off for a significant time--about 3 starts per hour is about all that is recommended for an electric motor, especially when accelerating a heavy inertial load like a compressor.

Your system should also avoid short operating times, such as having a deadband between kicking in and kicking out the compressors that is too close together. This will cause wear in the compressor unloading parts and will waste energy.

Hope this helps,

Jon.

Dear Mr.georgerin72,

The answer is theoritically, NO PROBLEM IN SIMULTANEOUS CUTTING-IN and CUT-OFF for both Compressors a a time.

But it is advisable to avoid this. If the Capacities of the Compressor is small it is OK, but large Capacity means, if the Compressors have to be put on DIESEL GENERATOR, it will pose problem, for frequent cut-Off or Cut-On.

DHAYANANDHAN.S

As others have said, the starting current of compressors is large so you may experience excessive voltage sag if you try to start both up at the same time (depending on the compressor size and your power supply capacity).

It is advisable to check that this voltage sag does not cause problems with the rest of your plant equipment.