can someone school me on contactor/starter wiring, please?

[396foxRN]

I collected parts here and there over the last couple of years while getting garage build quotes and finally having it built. Got it built last year, then ran 100A service to it underground from the home 200A panel. Since then, the garage has been on hold while getting the yard terraced and functional, and all I have done electrically in the garage is put in a temporary 20A plug and a temporary 50A welder plug so I could do minimal stuff in the garage when needed.

Now, it's time to wire things up. I have a Quincy 390 compressor, an 80 gallon upright tank, and a new Baldor 7.5hp single phase motor. I also have a new Cutler-Hammer DG323NGB 100A general duty safety switch and enclosure I can use for power cutoff near the compressor.

Now the question: I have two of these Eaton contactors with what looks like auxiliary normally open and normally closed circuits on it. The Eaton contactor is DILM40XTCE040D, with the NO/NC auxilliary DILM150-XHI11 XTCEXFBG11. I removed it from a relatively new but physically damaged commercial large HVAC unit in the salvage yard a few years ago. It was running a 3 phase 5hp motor for the blower.

Looking at the main contactor body label, it appears it is rated/capable of being used as a single phase unit at 230/240V with UP TO a 7.5hp motor. The auxiliary unit reads, as I take it, that it can be used for a max of 15A in either/or/both normally open and normally closed modes.

So, my intent on removing and buying this unit/units was to use it as a contactor/starter for my 7.5hp Baldor motor on the Quincy compressor, and to use the auxiliary contactor to start and run a fan-powered intercooler between the compressor and tank, so that the intercooler fan comes on whenever the compressor comes on, and goes off with it.




First, I am not a professional electrician. I am rather handy and have performed quite a bit of home wiring/rewiring/updates/panel changes/etc over the years through reading books and manuals and asking electricians when unsure of something. Is what I wrote above correct for what I am intending to do? Finally, is there a wiring diagram available anywhere for such a plan?


Thanks SOOOO much!

Doug

 

[alfredeneuman]

Motor starters have overload relays, contactors such as you have do not.
Eaton makes stand alone overload relays.
https://www.eaton.com/SEAsia/Produc...torControlProtection/OverloadRelays/index.htm
You could add the OL's or just buy a suitable motor starter for your application

Buying the starter could be less expensive in the long run, if you can return the contactor

 

[wyliesdiesels]

Your pics are blurry but looks like its rated for 7.5HP.

However i agree with the above.

Might be cheaper and easier to just buy a starter that already has everything you need.

Also, many PoCos have limits on HP ratings of motors.

Have you checked with your PoCo to see what their max Hp rating is?

That motor will draw a lot of power on startup

 

[Siegel1719]

I'm probably wrong but does that contactor use 24v to pull in the contacts? If so you would also need a transformer to use that contactor.

 

[W-Cummins]

Are you sure you can run a 390 with a 7.5 hp motor?? That's a 20hp pump and has a min rpm as it's pressure lubricated. 450rpm if I remember correctly. In any case I would not want to run it setup that way...


William....

 

[396foxRN]

Are you sure you can run a 390 with a 7.5 hp motor?? That's a 20hp pump and has a min rpm as it's pressure lubricated. 450rpm if I remember correctly. In any case I would not want to run it setup that way...


William....

Quincy recommends 7.5-15hp motors for the 390

 

[matt_i]

The pic where it says 24V50/60Hz would have me believing that its a 24VAC coil rather than a 24VDC relay.

So you'd need a control transformer, 50VA transformer like they use in HVAC with 240:24 windings would work out OK.

 

[396foxRN]

I took the advice and bought an Eaton setup made for a 7.5hp single phase compressor setup. Thanks for the info, guys!


Doug

 

[W-Cummins]

Quincy recommends 7.5-15hp motors for the 390

They do list it at 7.5 on the low end but it's a 20hp pump not a 15.
I was wrong on the min speed it's 400 ( been over 10 years sense I looked at the spec sheet)


Also I have talked to the Quincy engineers and they Don't really recommend it running on 7.5 hp if you look at the specs you will see that it takes more than 7.5hp of power to make the min rpm 400 @ 175 psi and produce 29.5 acfm.



The f340 is sold as a 7.5hp machine @26acfm and it takes 10hp on a 340 to get 29.64 out of it.



As I recall they said that you would have to run it below the recommended 400 rpm to keep the motor alive.



Have you ever run your 390 with your 7.5hp motor? What size pulley did you run?


My 390 with the 20hp motor pulled 137 amps on start up @ 480V 3 phase. That pump is a BEAST to spin up!


William....