Allen-Bradley motor contactor wiring diagram needed.

[Heavymetalmechanic]

I have my most recent air compressor project all finished up, all that's left is to reconnect the starter that came with it. I am having issues looking up instructions for correctly connecting the different leads. I have sat down and mapped all the terminals using my multimeter and manually actuating the contacts so I have a pretty good idea of how I should connect it, however I would feel better if I could reference a manufacturers instructions.

It is a Allen-Bradley model 500-c0d920, I have spent the last few hours google searching and sent an email to Rockwell Automation who I assume bought out Allen-Bradley.

The motor is a 5hp Bauldor, 20.6amp 1.15sf.

Can anyone help point me in the right direction?

 

[bsaint]

AB wont explain the wiring diagram because every application could potentially be different from the next.

The coil is the control circuit and the main contactor is the power circuit. Think of it as any type of automotive relay.

Assuming its a single phase 240v contactor with a 240v coil piston air compressor without low oil shutoff, manual on off, and so on this is how I'd wire it. L1 and L2 get hooked up to your mains. T1 and T2 get hooked to the motor. Take a wire and go from L1 to one side of the coil terminal. From the other side of the coil, the 2nd coil terminal, go from there to one side of a switched pole on your pressure switch (possibly L1 on your pressure switch depending on brand and style.) From the same pole but the opposite terminal (possibly T1 for the same reasons previously mentioned) go back to your L2 on your mag starter.

Does this make sense?

 

[Heavymetalmechanic]

Makes perfect sense, that's pretty much how I intend to wire it, minus the low oil shut off. But that gives me a great idea! There is a perfect spot for me to drill and tap my pump housing and install a low oil sensor, I may do that after my breakin period when I change the oil.

I'm saving up for a better motor starter, the one it came with has no cover and I don't think it has heaters. I will use it for the time being seeing as I can monitor it while it runs, but once I build the sandblasting shed against the garage it will need to be set up to run without supervision.

Thanks for confirming my understanding of it's wiring.

 

[bsaint]

Hey no problem. The AB unit is better than most replacement units. Can you put the starter in a different enclosure and buy heaters separate? AB has great support. I had a guy next to me at the AB dealer with a 1901 mag starter and AB had a drop in replacement.

You local AB guys can prob tell you at least the catalog number (aka part number with AB) of the heaters you need. Then I would just get them off ebay. I know that sounds shady but AB is major money and if your just doing it for yourself I dont see the harm in saving money.

 

[Heavymetalmechanic]

I will look into that, I'm going to pull my unit apart now and see if I can install heaters. The unit looks like this: (but not the same ratings)

http://www.surpluscontactors.com/sh...e-ac-115-120v-ac-25hp-45a-amp-contactor/31431

And I don't see where they would go, it has spots of clip on switches on the sides, but any heater elements would have to mount internally as far as I can tell. I'm going to have a friend take a look at it tomorrow when he gets back in town (commercial/industrial electrician).

 

[bsaint]

I'm pretty sure it's an external block that had the heaters in them. Google image AB 500 series overloads.

 

[Heavymetalmechanic]

Well I did not wait for my friend. I wired it up and it ran nice! I left all the valves open for 15 minutes for the first part of my pump break-in. When I closed the valves and the motor loaded up everything quit. Uh-oh... Double check my wiring and I think I ended up putting 240V through my 120V starter coil. No continuity across the coil anymore. I will be stopping at a recycling outfit before work tomorrow, the website leads me to think they have what I need.

Serves me right for being impatient and working a little too far out of my comfort zone, but nobody got hurt and it won't be an expensive learning experiance.

Thanks for the input everyone, it was appreciated.

 

[bsaint]

Oh man. Yea a 120v coil you would be coming back to neutral instead of L2! The coil should have the voltage on it. I made the same mistake once. I was wondering why the coil pulled in so hard!

 

[Heavymetalmechanic]

Yup! It made a good smack noise when I first turned it on. I hade to scrub a layer of something off the coil to find that it was marked with 120V. Hindsight being what it is I wish I had done that first.