# Tricky 20HP Motor Wiring

Joined Dec 24, 2021
2
I'm working on a 3 phase 20HP motor which its wiring does not match the the name plate.
It does not have the traditional 9 or 12 wires sticking out the side which can be reconfigured for 230v/460v.

Splitting it apart reveals a total of 24 wires, 9 pairs, 1 triple, and L1,L2,L3.

Analyzing the below picture I would assess that L1-3 are in series with other windings which would indicate it is in 460v configuration.
But the triple group would indicate 230v configuration.

Does anyone else have the opinion this does not match the STAR-Y name plate?
Any insight on what this is wired for? (Voltage & Star vs Delta).

My goal is to wire this for 230v.
The plan would be extend the leads out the service port and identify/label them accordingly. (If I can make sense of the 9 or 12 to move out.)

#### LowQCab

Joined Nov 6, 2012
4,216
With none of the Windings identified, this will be a total crap-shoot.
Take it to a Motor-Rewinding Shop, they may be able to figure it out.
It might be easier just to let them rewind the Motor specifically for your exact Voltage Supply,
( it's not likely to be exactly 230-Volts,
unless your building is supplied with a "High-Leg" 3-Phase System ).
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Joined Jul 18, 2013
28,770
These may help maybe.

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#### LowQCab

Joined Nov 6, 2012
4,216
Valuable Data Max,
Thanks.
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#### LesJones

Joined Jan 8, 2017
4,212
My first step would be to put labels on all the pairs and make a table of resistance readings between these 9 points , the point with three wires joined together and the L1, L3 and L3 wires. After looking at this table it may be necessary to separate some of the pairs to fully understand how all the windings are connected together. with the limited information we have at the moment I would guess that the three wires connected together are the star point. I am wondering if the motor has been rewound and is no longer easily
configurable to work on 230 and 460 volts.

Les.

Last edited:

Joined Dec 24, 2021
2
Thank you all for your insight.
I agree LesJones, I will wire map it as is, then cut all of the pairs, and diagram that out.

#### LesJones

Joined Jan 8, 2017
4,212
Do resistance measurements before splitting the pairs. That MAY give enough information. If not you can split the pairs to clarify what you have found.

Les.

#### LowQCab

Joined Nov 6, 2012
4,216
If You don't Re-Wind Motors for a living, you're just guessing,
and you will very likely "wind-up" with an expensive, and smoky, experiment.

Then You can take it to a Motor-Rewinding-Shop and finally get it done right.
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