Wiring 5hp motor

[harvey4804]

I just got a new GE 5hp 220v motor for my air compressor. The wiring diagram shows 2 wires going to the motor, one wire is labeled "UN-GROUNDED LINE" and the other is just "LINE"(?) and the cord going to it has the usual black, white, and green (gnd). I'm assuming they assume the consumer has enough common sense to know where to put the ground. where do the b/w wires get hooked up?

 

[JBurgess]

like this:

 

[harvey4804]

Thanks!!!!

 

[harvey4804]

So I guess Black is known as un-grounded line?

 

[JBurgess]

In a 110 volt circuit black is ungrounded.
In a 220 volt circuit both wires are ungrounded.

 

[harvey4804]

so... would it matter where they go if there both ungrounded?

 

[JBurgess]

so... would it matter where they go if there both ungrounded?

No it wouldn't matter. I just marked B and W in case someone looked at the photo for wiring a 110 volt motor.

In some other countries they have 220 volts with one wire grounded and one ungrounded.

 

[harvey4804]

got ya. thanks again!

 

[Norcal]

No it wouldn't matter. I just marked B and W in case someone looked at the photo for wiring a 110 volt motor.

In some other countries they have 220 volts with one wire grounded and one ungrounded.

And in the USA 110/220 died in the first half of the last century, there ain't no such thing anymore.....

 

[JBurgess]

And in the USA 110/220 died in the first half of the last century, there ain't no such thing anymore.....

I guess makes me almost old enough to retire.


In a 120 volt circuit black is ungrounded.
In a 240 volt circuit both wires are ungrounded.

Fixed for the younger generation.

 

[harvey4804]

I learn something new every day

 

[harvey4804]

Just my luck... I wire it up and the motor just :"humms". I swapped the White and Black wires just to see if it made a difference, and it did the same thing. I have just about given up on this dang compressor.

 

[harvey4804]

Oh, I even got the actual connection diagram from Regal-Beloit too:

 

[JBurgess]

Please don't take offense if my questions seem dumb, no offense intended.

Is the motor getting 220 volts?
Will it start without the belt(s) on?
Can you turn the motor over freely without the belt(s) on?
Does the compressor turn over by hand?

 

[harvey4804]

no prob! Ill take all the help I can get!

-yes its getting 220/240v (plugging it into my 30a dryer outlet.)
-wont start with the belt on or off.
-I can turn the motor and compressor freely, belt on or off.

 

[JBurgess]

My first guess would be your adapter for the dryer plug is wired wrong and you are only getting 120 volts to the motor. Is it a 3 or 4 wire plug?

 

[harvey4804]

3 wire. no adaptor. outlet looks like this:

 

[D KRAGER]

Look at the wiring diagram again. Where the diagram says line (2 wires) that would be the white and black. Then make sure the other wires going to the motor are on the correct terminal, they should be numbered.

Some motors like that can be wired either 110 or 220 by switching around the internal wires. I'm guessing something isn't in the right spot.

 

[harvey4804]

as far as I can tell the wires are in the correct locations (color / number). the motor doesn't have a 110v option, its a 240v only.

 

[JBurgess]

I assume you wired the plug like this:

Best to check voltage with a voltmeter.

Lacking that a picture of the wiring in the pressure switch might help.

Is this the same problem the old motor had?

You might also check if one of the wires fell off the starting cap, usually under a metal dome on the motor

 

[harvey4804]

Ive got my Fluke in truck, I'll meter it tomorrow after work.

the plug is wired as pictured.

the old motor was extremely packed with saw dust, after I cleaned it out it didn't want to get up to speed so it seemed, but it DID run for a minute or two then slowed to a stop. ordered new start and run caps and didn't fix the problem.

I'll have to check the caps as well... didn't think of that, being a new motor and all.

 

[Norcal]

I assume you wired the plug like this:

Best to check voltage with a voltmeter.

Lacking that a picture of the wiring in the pressure switch might help.

Is this the same problem the old motor had?

You might also check if one of the wires fell off the starting cap, usually under a metal dome on the motor

WARNING WARNING That device is NOT a grounding device!


A 3-wire dryer or range receptacle is a dual voltage as they both require 120/240 volts (0r 120/208 in some multi-family units), which means there are two "hot" legs and one neutral, this is because the National Electrical Code used to allow grounding the frames of clothes dryers & cooking equipment to the neutral (only allowed in existing installations now). If one looks close at the picture on the face of the receptacle it reads: "30A 125/250V " ,a 30A 250V is a grounding device......

 

[JBurgess]

WARNING WARNING That device is NOT a grounding device!


A 3-wire dryer or range receptacle is a dual voltage as they both require 120/240 volts (0r 120/208 in some multi-family units), which means there are two "hot" legs and one neutral, this is because the National Electrical Code used to allow grounding the frames of clothes dryers & cooking equipment to the neutral (only allowed in existing installations now). If one looks close at the picture on the face of the receptacle it reads: "30A 125/250V " ,a 30A 250V is a grounding device......

True but 250.60 under the old numbering system required it originates from the service entrance equipment, so it cannot originate from a sub panel fed by a 4wire feed.

At the point it is required to originate, grounded and grounding conductors are bonded. The receptacle could be changed to a grounding receptacle without changing the feed to it if it was wired to code.

It certainly would not pose a greater hazard than the shell of the dryer that is grounded to it currently.

It is used as a combination neutral and ground conductor to the dryer.

 

[harvey4804]

my ground/neutral is terminated to the motor case, so im still good right?
I am getting 240 correct?

 

[JBurgess]

You would still get 240 volts.

The discussion was the receptacle is not being used as designed.

 

[Norcal]

True but 250.60 under the old numbering system required it originates from the service entrance equipment, so it cannot originate from a sub panel fed by a 4wire feed.
At the point it is required to originate, grounded and grounding conductors are bonded. The receptacle could be changed to a grounding receptacle without changing the feed to it if it was wired to code.

It certainly would not pose a greater hazard than the shell of the dryer that is grounded to it currently.

It is used as a combination neutral and ground conductor to the dryer.

That requirement was when SE cable was used to feed dryers since the neutral is uninsulated , a 10/3 NM cable could be used from either the SE panel or a subpanel, and it is not a grounding conductor it is a neutral that was allowed to have the frame of a appliance connected to it for grounding.

 

[JBurgess]

That requirement was when SE cable was used to feed dryers since the neutral is uninsulated , a 10/3 NM cable could be used from either the SE panel or a subpanel, and it is not a grounding conductor it is a neutral that was allowed to have the frame of a appliance connected to it for grounding.

Agreed.

I guess it was a local amendment that 10/2 with ground was used if it orginated from a SE Panel. Locally that all I have seen for a 3 wire dryer except for some older K&T

 

[Norcal]

Agreed.

I guess it was a local amendment that 10/2 with ground was used if it orginated from a SE Panel. Locally that all I have seen for a 3 wire dryer except for some older K&T

10/2 W/G was never acceptable for a dryer, the grounding conductor is not permitted to be used as a current carrying conductor. That is not saying it was not done, just not code compliant.

Locally, it was common to use 6/3 aluminum SE cable for range & dryer circuits, then as long as it originated from the service equipment it was allowed, I never liked it but that was the way it was.....

 

[comedyman809]

ungrounded just means another hot line. youll have 2 hots a ground in a 220 circuit.

110 will have 1 hot line a neutral and a ground......to be honest, neutral eventually makes its way back to ground.

so technically neutral is ground.
i have had to tap off a 220 line(ungrounded) line to get 110 by using a hot and the ground to wire something for 110.

i also have a machine at my plant that has a transformer that is 2 480 lines coming in, and on the secondary, its 240vac on one line, and on the other it is 0V. and that feed another component that is 220v.

that is strange to me but 1 line is 220 and the other is 0.

 

[harvey4804]

So yeah... anyway... any other ideas of why my motor wont run?

 

[burleymike]

When all else fails take it to to a motor rebuild shop. They will know how to wire it and they can test the caps, which almost sounds like the problem. They will probably not charge much either to do this.

 

[Freejack]

While I am not able to explain why it won't start with the belt off, that is definitely not a 5 hp motor. While the HP field is almost too obscured to read, it appears to read 1 and the Frame size is listed as 56H. No 5 hp motor I know of would be able to fit into a 56 frame size, even at 2 pole speeds.

Jake