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Your 3 phase unit should not have a capacitor. I'm guessing it's single phase. If it's a single capacitor than the compressor should not be going to it also. To test the motor, common to start plus common to run should equal the ohms you get between start and run. For instance, 1.2 ohms+ 2.2 ohms= 3.4 ohms. Follow the wiring diagram on the inside of the door, send model number!!
telepathy do not work that hot as in hollywood movies...
you need to provide a model or at least if this is three phase or single phase...
single phase is easy, you have cord with three wires, earth, active and neutral.
you need to open connection box on your compressor and you will find three wires there terminating in junction box, earth connect to earth (usually green or green with yellow stripes), then you have your neutral (usually brown or black) and active (usually blue or red), connect them, do not put cover on yet, plug cable into the power point and switch on/off power. check if motor is rotating in correct direction, if fuses are not blown... if motor is rotating in wrong direction - switch power wire with neutral wire, it just meant that you wired it in reverse...
A 3phase motor cannot be rewired to run on single phase power. You need a phase converter. A 3-phase motor will only run on 3-phase power, and a phase converter will convert single phase power to 3 phase. Just google phase converter. There are two basic types, electronic and rotary. The rotary type are more powerful and efficient, but lot's more expensive than the electronic ones. Your only other option is to replace the motor with a single phase motor.
Good luck.
If the electrical 120 volt source is single phase, the only way to run this motor is with a single phase to three phase converter. Best to sell the three phase motor and obtain a similar horsepower 120 volt single-phase capacitor-start motor (1750 RPM) for the compressor. You would also require a 3-phase pressure switch for use with the 3-phase motor. Hope this helps!
You will use two of the original three wires. Not knowing if you have a motor starter and how it is wired makes it impossible to give you details.
BE AWARE that a 7.5 HP single phase motor is going to draw a massive starting surge compared to a three phase motor. I assume this is on a 240 volt system as it would NOT be practical to use a motor that size on a 120 volt system.
Expect to require around a 30 to 50 amp single phase feed to the motor.
The motor itself should have a sticker which describes the wiring for 115. It is a small change involving a single wire moving from one pole to another inside the motor starter cap (the bump on the motor itself).
Looking at the model number, it appears to be a 3 ton. (36,000 btu) Most all residential units are single phase and most all commercial are 3 phase. One way to tell, look to see if the compressor has a capacitor. 3 phase never use capacitors on the compressors as they are not needed. Some residential units have a "Dual" capacitor. That is, it has 3 terminals, 1 common, 1 for condenser fan motor, and 1 for the compressor. Also, this info should be printed on the unit's lable.
Good Luck and hope this helps.
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