220v 3phase question...

[machinist mountian man]

I have a Baldor 5hp 220v 3phase elect motor on a Qunicy air compressor, w red blk, blue, and white wires...... do i assume the r/bk/blu wires are Hot and white is nutral ?? each wire connecting to a hot leg from panel? and white wire go's where ??? feelin kinda dumb-**** right now but gotta ask for help is wise in this situation....

 

[walrus]

I have a Baldor 5hp 220v 3phase elect motor on a Qunicy air compressor, w red blk, blue, and white wires...... do i assume the r/bk/blu wires are Hot and white is nutral ?? each wire connecting to a hot leg from panel? and white wire go's where ??? feelin kinda dumb-**** right now but gotta ask for help is wise in this situation....

There should be a wiring diagram on the motor? Do you have a 3 phase service?

 

[Milton Shaw]

When you get it hooked up check which direction the motor/compressor is turning. Switching any two legs of a three phase motor will reverse the direction. On compressors running the wrong direction won't make it pump a vacuum instead of pressure but it will affect the oiling of the compressor crank. Most compressors I have seen viewing from the pulley side the rotation is clockwise. It should have an arrow somewhere on pulley or compressor.

 

[larry_g]

I believe you would have a three phase star wound motor.

http://www.djtelectraining.co.uk/downloads/ADL 3Ph SuppliesSystems.pdf

lg
no neat sig line

 

[jerryd68]

I will not have a neutral wire for a 3 phase motor, is it a single voltage motor?

 

[wyliesdiesels]

I have a Baldor 5hp 220v 3phase elect motor on a Qunicy air compressor, w red blk, blue, and white wires...... do i assume the r/bk/blu wires are Hot and white is nutral ?? each wire connecting to a hot leg from panel? and white wire go's where ??? feelin kinda dumb-**** right now but gotta ask for help is wise in this situation....

3 phase motors DONT need nor have a neutral. So your motor should have 3 hots and a ground. The white wire MIGHT be the ground and its just colored wrong. If thats the case, i would wrap some green tape around it.

I have to ask- do u have 3 phase service? And what type/voltage? Some motors will only work on certain voltages but most are multi-volt!

And as already mentioned, check your rotation!

 

[machinist mountian man]

Ok thanks everyone... I will post picts w/ intel/ panel ect. in a few days. for more ideas and solutions.... once again "Thank-you-all " ..

 

[larry_g]

3 phase motors DONT need nor have a neutral. So your motor should have 3 hots and a ground. The white wire MIGHT be the ground and its just colored wrong. If thats the case, i would wrap some green tape around it.

You might want to look at the link I posted above.. And do a bit of your own research on star or wye wound motors.

lg
no neat sig line

 

[wyliesdiesels]

You might want to look at the link I posted above.. And do a bit of your own research on star or wye wound motors.

lg
no neat sig line

Umm, I dont know if u've ever worked on or hooked up 3-phase motors but some of the info in the PDF u linked to is wrong. I work on 3-phase motors everyday at work. We have thousands of 3-phase pumps in the field, most with their windings wired in delta configuration for 480v service and the rest wired in wye configuration for 240v service, none of which have a neutral run to them. Hell, half of our pump main service panels are fed by 3-wire service and dont even have a neutral at the meter socket! A 3-phase motor does NOT need a neutral! Just yesterday i worked on a dual voltage motor, and wired the winding leads in wye(aka star) configuration for low voltage 240v operation. But i didnt run a neutral to the motor- just 3 hots and a ground!

I dont need to do any research because i work on this suff everyday! U may want to google the subject yourself! I googled it myself even though i knew the answer and heres one thread for your reading pleasure: http://www.electriciantalk.com/f2/do-3-phase-motors-require-neutral-3892/

I would note too, that that PDF is from the UK. They MIGHT do things differently there and run a neutral to a 3-phase motor, dont see why they would cause its not needed. But u never know.

The main point is, a properly running 3-phase motor should be pretty close to a balanced load and any imbalance is balanced between the 3 phase legs. A neutral is used and needed for single phase loads, of which a 3-phase motor is NOT!

 

[hidollartoys]

Play nice boys.

 

[jerryd68]

Sorry, I didnt mean to come across as terse, just saying that he will need to know a few things about the motor, like if it is a single voltage , and how many wires from the windings.

 

[wyliesdiesels]

I meant that it will not need a nuetral, I also work on 3 phase motor's everyday at work, from 1/2 hp on up, most on vfd's with speed control. I do understand how to hook up a delta or wye configured 3 phase motor as I have ran hundered of circuits for them from the distribution to the motor. Built many control panels and written programming to run them. Bottom line you will not need a neutral.

Just go back and edit your post!

 

[larry_g]

Umm, I dont know if u've ever worked on or hooked up 3-phase motors but some of the info in the PDF u linked to is wrong.
(big snip..)
The main point is, a properly running 3-phase motor should be pretty close to a balanced load and any imbalance is balanced between the 3 phase legs. A neutral is used and needed for single phase loads, of which a 3-phase motor is NOT!

I will stand corrected. The only thing I can assume is that the Y point is brought out for some reason, or the ground is the wrong color. It will be interesting if the OP will post pictures of just what he has.
\
lg
no neat sig line

 

[BreeStephany]

is it possible that you could have 120V motor controls on the compressor? generally speaking, almost all controls are wired for 208V/240V 1ph so you don't have to carry a neutral for controls, but it could be a possibility, or it could be a mismarked ground...

Best way to tell what the situation is to see pictures

 

[wyliesdiesels]

I will stand corrected. The only thing I can assume is that the Y point is brought out for some reason, or the ground is the wrong color. It will be interesting if the OP will post pictures of just what he has.
\
lg
no neat sig line

No mystery here. The y point you're referring to is the low voltage configuration for the windings of a 'wye connected' multi-voltage motor. Yes, the leads, which connect to certain points of the windings, are brought out of the motor into the j. box to allow the motor to be wired for low or high voltage operation, 230v and 460v being the most common voltages.

A 9 lead wye connected motor wired for low voltage operation will have 3 leads connected together, forming the common point, aka y point, and then each of the 3 feed wires get 2 of the 6 remaining leads.

Do a google search and u should be able to find the different wiring diagrams for motors!