Mag starter help

[terryo1965]

I have an old IR T30 2 stage compressor that was converted to a 3HP 1ph motor before I got it. It was originally a 5hp 1ph unit. My problem is as the pressure starts building there was a "banging" noise out of the starter box. I took the cover off and I can see the magnetic button going in and out creating this popping noise. I was told it could be low voltage to the starter causing the coil to not "hold" and I need more robust wiring to the starter.

The wiring from the starter to the wall plug is 12 gauge and the plug end is a 20amp 220v. I am running a 20amp breaker. I thought this might be the problem but I was reading the starter information that came with the unit and it spec's out 12 gauge wiring to the starter.

Do you think the wiring to the starter should be 10 gauge? Is the 20amp breaker too small?

I have been running the compressor for a couple years with this setup and it has worked okay. The popping started right before the pressure switch would turn off the compressor off but after several months it is popping at lower and lower pressures.

Any input would be appreciated!
Thanks,
Terry

 

[Zrexxer]

Could you have a 220V coil that's only being fed from one leg? Some coils are 120V and it may have been wired wrong.

 

[terryo1965]

I think the starter was wired correctly. I was a used unit that came out of an Detroit Edison service center so I would hope they know what they are doing!! Plus the thing has worked okay for a couple years, although it doesn't get a lot of use.

 

[A_Pmech]

Is the contactor buzzing loudly?

 

[terryo1965]

Nope, no buzzing. Just a popping noise when the thing releases. Almost sounds like a backfiring noise.

 

[71flh]

Maybe you could look at the thing and see what the ratings are.
Maybe measure the voltage with and w/o a load, and across the coil when running.

 

[Gary S]

It sounds to me like your pressure switch is malfunctioning and cycling the mag switch until the compressor stops.

 

[terryo1965]

Thanks for help guys, these are good ideas. I never thought of the pressure switch, that makes sense.

 

[Fred43]

The presure switch is the easiest point to check for pitted contacts, dirt, loose connections. If this does not solve the problem check the stater for the same types of problems. Check for loose wires !!!