Unmarked leads 3 phase motor

Thread Starter


Joined Dec 20, 2020
The label reads
S# 311P872
Fr K56
Type A
Ser GJ72
Type FS
Ser factor 1.15
Code J
Hrs. Cont
Insulation Class B*
RPM 1425/1725
Hz 50/60
Volts 208-240/440-480
Ph 3
Amp 4.7/2.35
HP 1 1/2

I assume the illegible smaller label is the wiring diagram.
This motor was used to power a small air compressor,
I wired this motor over 10 years ago. Some of the wire labels were missing then.
I have no clue how I went about wiring the motor originally. I had wired my small machine shop and
barn for 3 phase.
The wires are all black and used the scheme of 1T 1P through 6T 6P.
A tree pulled down my power line and in process of upgrading my electrical system here I stand.
I find many posts about identifying leads of all versions of 6 lead motors and 1 instruction for 12 lead delta but this I have not found the answer.



Joined Jul 30, 2017
I seem to remember the 12 wires will indicate that the motor can be wired either wye or delta. An ohmmeter check should show you the different windings.

"As with a single-voltage delta-configured 3-phase AC induction motor, common in-lead motor-terminal T1 should be connected to supply line L1, common in-lead motor-terminal T2 should be connected to supply line L2, and common in-lead motor-terminal T3 should be connected to supply line L3."

Would this help?

How 'bout this?

I would suggest a colored heat shrink kit and once you've discovered what's what, label the different coils with different colors to keep track of them.
Last edited:


Joined Nov 6, 2012
Here's an 8-by-10 Schematic that you can Print-out to scribble notes on.
3-Phase Motors are seldom Wired in a "Wye" configuration except in special circumstances.
After you Identify all-6 Windings,
measure the Resistance of all of them,
they must be within ~10% of each other or less.
If you have 3-Windings with close Resistances,
and the other 3-Windings are close to each other,
but more than ~10% different than the first-3,
STOP, and take the Motor to a Professional Motor Rewinding Shop
and pay them to figure it out.
They will properly connect all the Windings and
provide you with 3-simple Wires to supply power to.
They will want to know the Voltages that you are supplying the Motor with,
and whether or not it is a "High-Leg-System" or a "Real" 3-Phase Supply.
2- Different looking Transformers on the Pole = "High-Leg-System",
3- Identical Transformers on the Pole = "Real" 3-Phase Power.

On any 3-Phase Motor, swap any 2 Power Supply Wires to Reverse Rotation Direction.