12 lead motor 240-480 conversion

DrSparks

Senior Member
Location
Madison, WI, USA
I have a motor currently wired for 240 that I’m trying to convert to 480. I have 2 hours to get this job done. I’m stuck on this motor— the wiring doesn’t match to diagram. I’ve never seen this before anyone have any ideas? See pictures.



Sent from my iPhone using Tapatalk
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
The attachment marked 12 lead is the one you have. It is not Delta or Wye. It is HI-wye or LO-wye
That's exactly opposite of what the connection diagram on the motor is telling him...
The diagram on the motor is typical of an IEC dual voltage motor, designed for 230/400V 50Hz in which the motor is connected in Y for the High voltage and Delta for the Low voltage. The 400V 50Hz connection will work fine for 480V 60Hz.

What I was saying is that this motor is connected as the high voltage when that picture was take. If the previous user though that it was connected for 240V, then were incorrect. The motor would have run, but the peak torque would have been 1/4th of normal. If the load was light enough, they may not have noticed and it was running that way for a long time. I've seen that happen several times.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
It's confusing because the diagram shows two rows of terminals but the photo shows three rows. :?

It appears to be wired for both, which can't be.
 

MTW

Senior Member
Location
SE Michigan
Looks to me that it was rewound as a standard nine lead dual voltage voltage 60Hz motor. A second block was added to for the extra leads, and half the posts cut off to make clearance. Appears to be strapped for the lower voltage.
 

ActionDave

Moderator
Staff member
Location
Durango, CO, 10 h 20 min without traffic from wing
Occupation
wire pulling grunt
I have a motor currently wired for 240 that I’m trying to convert to 480. I have 2 hours to get this job done. I’m stuck on this motor— the wiring doesn’t match to diagram. I’ve never seen this before anyone have any ideas? See pictures.



Sent from my iPhone using Tapatalk
I don't know what is going on but you don't have a 12 lead motor, at least not in the top photo, you have a 9 lead motor.
In the upper photo it is strapped for the higher voltage.
I agree. Something is wrong that ain't write.
 

PaulMmn

Senior Member
Location
Union, KY, USA
I'm not an electrician, but I can follow diagrams... I think.

Looking at the picture with the actual wires and shunts, I'm assuming the connections are:

W2==U2==V2 <--- these are bridged by the horizontal shunts

U1 V1 W1
|| || || <--- these are bridged by the vertical shunts
L1 L2 L3 <--- the phase wires are connected here

If I'm reading the diagram on the inside of the lid properly, this thing is wired wrong!

I'm thinking this should be the low voltage wiring:

W2 U2 V2
|| || || <--- these are bridged by the vertical shunts
U1 V1 W1

L1 L2 L3 <--- the phase wires are connected here

And the high voltage:

W2==U2==V2 <--- these are bridged by the horizontal shunts

U1 V1 W1

L1 L2 L3 <--- the phase wires are connected here

This assumes that the phase wires connect on the 3rd row, the L1/L2/L3 markings.
But what do the Arrows indicate? That the phase wires connect on U1/V1/W1? In both cases?

I'm confused!
 

PaulMmn

Senior Member
Location
Union, KY, USA
After you said the bottom 3 bolts were sheared off...

Look closely at the markings... The sheared off bolts are U1, V1, and W1!

The other markings are hidden!!

edit:

And the arrows are showing that the phase connections are supposed to be on those missing bolts.
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
North of the 65 parallel
Occupation
EE (Field - as little design as possible)
That's exactly opposite of what the connection diagram on the motor is telling him...
The diagram on the motor is typical of an IEC dual voltage motor, designed for 230/400V 50Hz in which the motor is connected in Y for the High voltage and Delta for the Low voltage. The 400V 50Hz connection will work fine for 480V 60Hz.

What I was saying is that this motor is connected as the high voltage when that picture was take. If the previous user though that it was connected for 240V, then were incorrect. The motor would have run, but the peak torque would have been 1/4th of normal. If the load was light enough, they may not have noticed and it was running that way for a long time. I've seen that happen several times.
Your reading of the nameplate is certainly different than mine.

I figured that when the nameplate said 230/460, 60 hz, and didn't say anything about 50Hz or 400V then that meant that the motor was good for 230/460, 60 HZ. I know really weird that I would think they didn't lie on the nameplate.

There is one other scenario: (pton alluded to this)
The pic I sent of the 12 lead is still good, but one of the wye points is broken off, the motor is connected for 230V and only running on half the windings. It would be an excellent 7.5KW 230V motor

Or you could be right.
At 60Hz it would be a 460Y or 277D
(edit) whoops, make that 460Y, or 266D
 

iceworm

Curmudgeon still using printed IEEE Color Books
Location
North of the 65 parallel
Occupation
EE (Field - as little design as possible)
After you said the bottom 3 bolts were sheared off...

Look closely at the markings... The sheared off bolts are U1, V1, and W1!

The other markings are hidden!!

edit:

And the arrows are showing that the phase connections are supposed to be on those missing bolts.
Yep saw that. That's one of the reasons I thought the t10, t11, t12 leads/common connection was buried

(edit)
It certainly appears to be a 12 lead. Lowest number I can see is 2. Highest number is 12. A wye/Delta connection doesn't appear to be of any use. Parallel wye at 230V and serial wye at 460V will work. As jraef said, the motor is an IEC made for Wye/Delta. I'm thinking yep, "Was", and they didn't change the connection plate.
 
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