Hi there everybody, this is my problem' I have two 3 phase 10 hp compressors connected to one air tank, each compressor is on its own circuit and its own pressure switch at the moment only one compressor comes on because of the pressure switch, I’ve tried adjusting the other one to get it the same but it's to hard, what I need for each compressor to come on alternately, thanks
Namus

Hi there everybody, this is my problem' I have two 3 phase 10 hp compressors connected to one air tank, each compressor is on its own circuit and its own pressure switch at the moment only one compressor comes on because of the pressure switch, I’ve tried adjusting the other one to get it the same but it's to hard, what I need for each compressor to come on alternately, thanks
Namus
You need an alternator, the pressor switch control it

you need an alternator, the pressor switch control it

Is that what I ask for at the wholesale house?

One simple method is to wire in an alternating relay such as the one shown here:
Grainger Industrial Supply: Relay,Alternating 6C052 (http://www.grainger.com/Grainger/items/6C052)

Which will need to be connected into the control wiring of both motor starters/contactors.