Single Phase Double Capacitation Induction Motor, YL90L-4, CT043 Craftex Lathe - Motor Wiring and Control

MaxHeadRoom

Joined Jul 18, 2013
28,502
And an interesting thought is to just disconnect the starting capacitor and see what happens with a no-load connected start attempt. If it starts and then runs OK, you will know it is a start witch problem.
As per my post #24 in Dec ! ;)

This thread is taking on a life of its own!
 

MisterBill2

Joined Jan 23, 2018
17,760
As per my post #24 in Dec ! ;)

This thread is taking on a life of its own!
Max, or if not "a life of it's own", a time loop. The start capacitor is to help the motor start with some load, it will probably start without the start capacitor at no load, and that would be simple to verify.
And I think that the Chinese lathe motor that I saw about 17 years ago had colored leads on the motor windings. But that machine was a three phase machine, as I recall.
 

LesJones

Joined Jan 8, 2017
4,171
MisterBill2's comments about the wire colours made me think that if the motor had not been rewound the winding wires would be colour coded (Or marked in some way.) If this was not the case the point on the assembly line where the connection box was fitted would involve at least resistance tests to identify the winding ends. Even if this was done the direction of rotation would be random. Colour coding the wires would remove the need for any testing at this stage and the direction of rotation would be consistent. If the motor had been rewound for a different voltage to the original then the required capacitor values would be different to the original. The capacitors are the same value as marked on the motor information plate.
elissquires, Was the motor connection plate missing ? If you have it are there any links between the terminals on the underside ? (The side where the wires from inside the motor would have been connected to.)

Les.
 

MisterBill2

Joined Jan 23, 2018
17,760
MisterBill2's comments about the wire colours made me think that if the motor had not been rewound the winding wires would be colour coded (Or marked in some way.) If this was not the case the point on the assembly line where the connection box was fitted would involve at least resistance tests to identify the winding ends. Even if this was done the direction of rotation would be random. Colour coding the wires would remove the need for any testing at this stage and the direction of rotation would be consistent. If the motor had been rewound for a different voltage to the original then the required capacitor values would be different to the original. The capacitors are the same value as marked on the motor information plate.
elissquires, Was the motor connection plate missing ? If you have it are there any links between the terminals on the underside ? (The side where the wires from inside the motor would have been connected to.)

Les.
L.J. The TS has told us that the lathe had been placed on it's back resulting in the destruction of the original junction box. The result being that much was lost, including the original identification and connections. This was indeed unfortunate, and shows the flaw in letting unskilled help touch anything of value.
So now we are dealing with an unknown package in an unknown condition and are given not enough information.

My next suggestion is to test the motor for shorted turns and insulation breakdown, because other efforts have not solved the problem.
When all else fails, try something different.
 

Thread Starter

elissquires

Joined Dec 26, 2021
27
Hi all. Thought it was only polite that I wrap this up. Thanks to everyone for your input. For those of you who mentioned adding a 4th power control wire, you were right in the end. The original motor had poles for each end of each winding, and for each end of the starting and running capacitor that run in parallel (including the centrifugal switch). This allowed the motor to be run and reversed with the 3 x originally manufactured power control circuits (see photo 239 for the relationship between the power control wires). Unfortunately, that motor was toasted when they laid the lathe on its back and bathed the windings in oil (while ripping off all the wires to the motor). The new motor was wired with one winding in series with the capacitors in parallel circuit (see photo ending in 127 for wiring). I pulled apart the motor to see if I could separate the winding and the capacitors circuit but that was no go as the connection was buried in the motor. An electrician friend suggested (as some of you did) running a 4th power control wire from one side of the plug power wire to one end of the primary winding providing continuous 120v power. After much experimentation, and way too long, the configuration in photo ending in 501 runs the lathe perfectly in forward and reverse. The 120v wire runs at 9 amps, just as the motor placard advertises. Cheers.
 

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