I had just purchased an Ingersall Rand duplex compressor set up to replace our existing Quincy duplex compressor setup. The Quincy set up ran single phase and now the new one is three phase. We have a three phase 208v transformer to this operating panel which we ran two separate 30 amp three phase circuits from to the new compressor setup. Upon receiving the new setup the compressor setup was damaged in shipping and was repaired by the company's warranty service contractor along with an entirely new control box and control parts. I noticed the labeling on the new setup calls for 200v - 3 phase - 60 hz. and assume that the 208v we are feeding is fine because of the 10% over and under rule which puts me in that range. Let me clarify more - the control parts are stamped with a 208/240 volt rating but the motor is stamped 200 volts which I assume is for Japan applications. The system once hooked up to the 208v is not operating but when I force the starter in each motor runs fine which I am assuming is a wiring issue inside the control panel from the service work. My question is this - Do you think the 200 volt system is fine hooked up to 208 volt line feed and would you feel it would hurt the warranty on the system?

 

Using a 200V nameplate motor on a 208V system is the correct motor to use.

208V is the nominal voltage of the system (assuming very little voltage drop). But when you a supplying a motor, you have a fairly high current flow which causes a voltage drop across the wiring from the panel to the motor so the voltage at the motor terminals (under load) will be very close to 200V.