3-phase nine wire motor on 3 phase w/bastard leg system

[Slainor]

I have a new 3 phase 9 wire baldor motor that lists voltage at 208-230/460 and am attempting to hook it up to my 3 phase/220 system that has a 208v bastard leg. The house system tests out at:
A-ground=115v
B-ground=115v
C-ground=208v

A-C=220v
A-B=220v
B-C=220v

If I wire it as per it's low voltage diagram I get wires 6-5-4 as leads and (as I understand it) connect wires 7-1, 8-2, 9-3
If I arbitrarily assign any one of the three house leads to any of the 3 motor leads, as I assumed would be the case, I get less than the rated 3450 rpms, buzzing and smoke!
Anyone have any idea what I'm doing wrong?

 

[jraef]

The wild leg issue is irrelevant, don't get hung up on that aspect. Voltage to ground on a delta system by the way is also irrelevant, other than as the reference for your neutral tap between A and B.

Either;
1) you have misinterpreted the connection diagram, or
2) you are using a diagram that did not come with the motor and it is incorrect, or
2) the diagram that DID come with the motor is incorrect (it happens), or
3) the wires are incorrectly numbered, or
4) someone has re-wound that motor and it is no longert dual voltage, or
5) the motor is bad or,
6...) etc. etc.

In short, you need to do some troubleshooting. Eliminate the simplest possibilities first, it's far more likely to be one of those. Start with this: saying it is "9 lead" is not a universally descriptive term for anything other than the fact that it has 9 leads. You have to look very carefully at the manufacturer's connection diagram AND THE MOTOR NAMEPLATE and understand what it means.

For example:

"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> faq731-376

 

[waross]

It sounds as if you may be applying power to 4, 5, and 6.
No. 4, 5, and 6 are connected together and insulated. Power is applied:
A to 1-7
B to 2-8
C to 3-9.
This is the most common connection but all of jraef's comments are valid.
If you are applying power to 4, 5, and 6, you may well get smoke.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[petronila]

Hello Slainor

Be sure the motor is uncoupled.

Then identify the internal motor connection, if is Wye or Delta. How to do that? Take a tester put in continuity mode and test between leads 7 and 8, 7 and 9 & 8 and 9, if you have continuity between and only in this three leads (7-8&9) then you have an internal Wye. Is not you will have continuity between 1,4 and 9, 2,5 and 7, & 3,6 and 8 then you have a internal delta connection.

Second: If you are applying 220 V to fed the motor you most use a double wye or double delta connection, deppending what you find above, then follow the jraef instructions and you will connect the motor in righ way.

Third: Once you have the motor spinning then check the no load current ussing the clamp, you will have 20 or 30 % of full load current.

I hope this be usefull

Regards

Carlos

 

[Slainor]

Thanks for all the help. Motor is running beautifully.