[cadman56]

Just got a new Champion Air Compressor. 5hp, 60gal vertical tank, twin cylinder, 2 stage. Motor is a Baldor Reliance Industrial Motor 5hp, 208/230 volts, 23.5/21.5 amps. I have a 30amp breaker in my shops panel box that is not used. Is this OK to use amp wise? I will be running 8ga wire from the panel to a disconnect. Which leads me to my next question. I have a 30amp disconnect that I used for my old compressor, (2hp, 20gal tank), to turn the compressor on and off. On the inside cover of the disconnect it states that the max hp for the disconnect is 3hp. Can I still use this disconnect? If I can then I'm going to hard wire from the disconnect to the compressor. Note that my compressor does not have a manual or magnetic starter. Attached are couple of pics of the disconnect that I hope I can use. :trink39:

 

[73 wheelhorse]

First that compressor is 230 or 240 volts at 21.5 amps your 30amp breaker is fine but needs to be a double pole breaker not single pole which means it is two phases that disconnect is fine also if it is a double pole disconnect which means it disconnects two phases you will need some way to start this motor weather it be a manual or magnetic starter it needs to have a starter hope this helps pm me if you have any others questions
Doug (licensed Electrician)

 

[innoman]

You should be ok to use all the old stuff that you have.

 

[jimjimmyjames]

I am also a licensed electrician and would like to steer you the right way. Seeing as you do not have a motor starter, you will NEED to install a different switch. The contacts on the blade-type disconnect you have will not hold up to the inrush of starting your 5h.p. motor across-the-line. Your motor is drawing 21.5 amps at full load, but when it starts it is drawing much more than that. I would recomend installing either a manual starter or at least a switch rated for starting your 5 h.p. motor. Best of luck, Jimmy

 

[73 wheelhorse]

Steer you the RIGHT WAY is that not what I just recommended DUH

 

[cadman56]

Thanks everyone for the info. Yes, the breaker is a double pole and so is the disconnect, (double 30amp cartridge fuses). I just ran out to the shop and checked on the compressor motor again. It states on the nameplate that it is "thermally protected" and the manual states that the "5hp units furnished with thermal overload protected (TOLP) motors rated for 3450 RPM, 230 volts, 60 hertz, single phase do not require a manual or magnetic starter." There is a knob on the outside of the pressure switch for "OFF" and "AUTO". Not sure if I would use that to turn the compressor on and off or the disconnect. Or should I get some other device/switch to turn the compressor on and off? Here is a link to the compressor I have. http://www.tptools.com/p/184,91_5-HP-2-Stage-Champion-Centurion-Series.html It is item no. 8550-60DS. If you guys need any other info reply back and I'll get it for you. Thanks again. :trink39:

 

[73 wheelhorse]

If the compressor has the OFF and AUTO I would wire it straight to this disconnect then use that switch to turn it on and off just make sure the breaker that feeds that disconnect is 30 amp double pole hope this helps
Doug

 

[mbkerk]

Cadman56...

Check out this thread.

http://www.mytractorforum.com/showthread.php?t=53961

 

[Grateful11]

We have I think 7 full-time electricians where I work. We have an old saying
"Electricity is not a hobby". ;-)

 

[Grogan14]

As Jimmy stated, that disconnect is not designed nor listed to carry the starting current of your 5-hp motor. Starting current is often twice your running current or more, and can be up to something like 9 times as much, depending. You'll need a disconnect listed for at least 5-hp, with some form of 30-amp dual-element (time delay) cartridge fuses. You'll use the switch on the unit.

You may have problems with the 30-amp breaker feeding this disconnect tripping - again, due to starting current. Since you'll have the 30-amp cartridge fuses providing over-current protection, code will allow you to step up the size of that circuit breaker. It's been a little while, but it's something like increasing it one step at a time, until you're no longer tripping it, up to some maximum value. So, you may find you need a 60 or 70 amp breaker, and, even though you're thinking that can't be right, as you're only running
#8 wire, it is allowed by code, as those cartridge fuses will not allow that wire to see more than 30-amps, other than during their time-delay.

And, yes, I'm a former electrical contractor.

 

[cadman56]

Thanks everyone for the info. I just back on the forum. I was on vacation for a couple of weeks and right before I left my HD went out on my pc. I installed a new HD, got that set up and then my ISP had server problems and I was without internet for 3 days. Anyway, I got my computer problems fixed, so on with the compressor. I went to a local electric distributor that I deal with and got a new box rated at 10hp max. I mounted the box on the wall and then ran new 8ga wire to it. Runs like a champ and no problems with it. I can run air tools now and don't need to wait for the compressor to catch up. Here are a couple of pics of the new box. :trink39: