Compressor Project... Have Some questions

[rustybill]

Hi All,

A friend of mine gave me this Ingersoll Rand compressor. It's a T30 pump, Baldor 5HP 3 phase motor, Square D mag starter... I've been sitting on it for a while, waiting for a good deal on a single phase 5hp motor. I came across two of these Baldor motors, (p/n CL1410TM) on pressure washers that were headed for the scrap yard.

I'm going to degrease the tank and paint it, swap the motor, rewire, and put into service.

I have some questions regarding the wiring. The motors that come from the pressure washers did not have mag starters. I'm assuming it would still be beneficial to run one from a motor protection stand point here? Does anyone have a schematic for how to wire the mag starter and pressure switch?

 

[Cyberbear]

A magnetic starter is definitely a proper way to operate your unit, and there should be plenty of info for hooking it up on the Net. You didn't mention it but I'm assuming your single phase motors are 240 volt, if so, you can use either line voltage (240 v) or 120 volt for the control. You'll need to choose a method for switching the unit on, depending how sophisticated you want it to be. I buy all of my motor controls on ebay for the best prices.

 

[matt_i]

The contactor (mag starter if you must) is mainly good protection for the *pressure switch*. You appear to have a very rare single phase overload heater section, one of very few on the planet . Heaters will have to be sized and sourced, as there is the possibility that its incorrect for your motor HP. It will theoretically protect the motor against overload, but that function can be done by circuit breakers or old school fuses. Nothing gained from protection against phase loss as nothing would work anyway.

The wiring is pretty simple, power side L1 and L2 come from your residential power, T1 and T2 go to the motor. Control side, there is the relay-coil and the normally closed pressure switch, and the overload normally closed contact. All three of these are wired in series. You must pay attention to the requirement for the coil voltage, it could be full line voltage, or require a control transformer. So the control side also needs a source of AC power.

 

[Cyberbear]

A contactor is simply an electrical switch usually operated by a remote off-on switch of some type and usually protected by a circuit breaker. Contactors are most often used for such things as a large bank of lighting fixtures that require more amps than a simple 15 amp off-on switch can handle. My shop had two banks of overhead lights that pulled 25 amps. each when turned on, a simple single pole 15 amp. wall switch wouldn't last long when turning these lights off and on, so a lighting contactor is needed for each separate bank of lights.
A magnetic starter is mostly used to control a motor by way of an off-on switch. Unlike the contactor, a mag starter has over load protection devices that sense a motor current over load situation and automatically shuts down the motor when too many amps are being drawn. The operating coils of both contactors and mag starters draw but a few amps during operation. Over loads act like a circuit breaker but are able to more closely monitor the motor amperage using internal heater elements, thus providing thermal protection to the motor as well. It is a little awkward to explain a simple three wire start/stop station, but if you contact the manufacturer of the mag starter, they should be able to provide a simple to follow wiring diagram. All motor starters are wired similarly, and if you were local I'd hook it up for you in 5 minutes. I spent 12+ years in the motor control trade and used to do this for a living. I still enjoy hooking up all my own machines after being retired these many years. There is always more than one way to do something.

 

[matt_i]

Here is my back-of-envelope sketch A few liberties were taken in the ANSI symblogy

 

[nadogail]

Looks Good to me. What is it you don't understand?