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

Thread Starter

elissquires

Joined Dec 26, 2021
26
Good Morning,

As per subj, I have a problem with wiring/controlling a YL90L-4 electric motor on my older CT043 Craftex lathe. I've taken a bunch of pictures and done lots of testing, the results of which I'll post below. The government agency that I bought if from laid it down on its back and mashed the connections totally. None of the wires were labelled so I applied arbitrary lablels. How do I successfully wire this motor to my forward and reverse lathe switch. Please note that this is a made in China motor so where the standard voltage is 220v, so not both sides to a neutral, just 220v across 2 wires. As you can probably see, I'm not an electrical guy so you'll have to be explicit with any recommendations.

There are 3 Power Control wires (plus a ground to the motor casing) coming from the fwd/rev switch to the motor. I've labelled them as follows (see photo 1):

Power Control-Black1 (PC-B1);
Power Control-Black2 (PC-B2);
Power Control-Black3 (PC-B3).

I've tested them with power to the machine. Results are as follows:

There is 220v between PC-B1 and PC-B2 in forward and reverse;
There is 220v between PC-B1 and PC-B3 in reverse (0v in forward);
There is 220v between PC-B2 and PC-B3 in forward (0v in reverse).

I took apart the motor and traced and tested the wires. I've labelled the wires as Motor Top (MT) and Motor Bottom (MB), based on which hole in the casing that they emerge from, with color code as per above. Results are as follows:

MT-R1 has continuity with MB-R1 with a resistance of .9 ohms (Winding 1);
MT-R2 has continuity with MB-R2 with a resistance of .9 ohms (Winding 2);
MT-Black enters the case and goes directly to one side of the centrifugal switch, then to one pole of the running capacitor;
Other side of centrifugal switch (switch closed for start/open for run) goes to one pole of the starting capacitor;
MB-Blue enters case and goes to second pole of both capacitors (they run in parallel);
Capacitance between MT-Black and MB-Blue with centrifugal switch in starting position (closed) is 185 micro farads (which is in the ballpark as the starting capacitor is 150 micro farads and the running capacitor is 20 micro farads).

I connected the motor as follows:

PC-B1 to MT-R1 and MT-Black
PC-B2 to MT-R2 and MB-Blue
PC-B3 to MB-R1 and MB-R2

The motor will run in forward and reverse for 3 to 4 seconds before tripping the internal switch (8.5 amp breaker). All fuses have been checked serviceable. No smell of burning. Panel breaker does not trip. Put a clamp on ammeter on PC wire and measured 13.5 amps so the internal breaker is working as advertised.

Any help would be much appreciated.
 

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Thread Starter

elissquires

Joined Dec 26, 2021
26
Unfortunately, that's as clear as I can get it. It's a pretty old machine and label (although I think it was only used once or twice).
 

MaxHeadRoom

Joined Jul 18, 2013
24,980
Did you use the lowest range on your meter to measure the windings, you should have two different values, one for the start winding High res, and low res for the run.
Is there no way you can post a larger DSC_0045?
 

LesJones

Joined Jan 8, 2017
3,701
Hi Max,
If you click on the square box with the arrow in it at the top right of the screen it opens the picture in a new page. On this page you can zoom in and out on the image using the scroll wheel on the mouse while holding the Ctrl key down.
This is the result of a screen capture after zooming in.
Screen Shot 12-27-21 at 03.41 PM.PNG
Les.
 

MaxHeadRoom

Joined Jul 18, 2013
24,980
OK deciphering the drawing it seems that they use a 3ph contactor for a reverser, the motor is fed through a O/L relay, FR, the two windings are U1-Z1 & U2-Z2 , the odd thing is the diag. does not show any capacitors, but looking at the photo's, the capacitor is seemingly fed through a hole in the enclosure so may be it is omitted in the DWG as it is not considered external.
One direction would be U1 connected to U2 and Z1 connected to Z2 , with reverse U1 & Z2 - U2 & Z1
 

Thread Starter

elissquires

Joined Dec 26, 2021
26
Thanks Max. I'll take a look. The motor placard has Z2, U2 and V1 marretted together. In my nomenclature that would be MB-R2, MB-R1, and MB-Blue. Then PC-B2 would be connected to MT-R1 and PC-B3 would be connected to MT-Black and MT-R2 giving 220v in forward? The motor placard is confusing in reverse... I'll think on it some more. Still confused.
 

LesJones

Joined Jan 8, 2017
3,701
I would expect the two winding to give different resistance readings. (The lower reading being the main winding.) See if you can find a way to get a better reading of the low value of resistance. For example the windings in series and pass a reasonable DC current through them. (Say 5 to 10 amps using 1 or 3 car headlamp bulbs in parallel) in series with the windings fed from a car battery. Measure the voltage across each winding. The one with the lowest voltage reading will be the main winding.
Report your findings.

Les.
 

Thread Starter

elissquires

Joined Dec 26, 2021
26
I would expect the two winding to give different resistance readings. (The lower reading being the main winding.) See if you can find a way to get a better reading of the low value of resistance. For example the windings in series and pass a reasonable DC current through them. (Say 5 to 10 amps using 1 or 3 car headlamp bulbs in parallel) in series with the windings fed from a car battery. Measure the voltage across each winding. The one with the lowest voltage reading will be the main winding.
Report your findings.

Les.
Thanks Les. I'll give that a shot. Got a spare charged battery sitting in my shop for odd jobs. Here's a schematic taken from a youtube video that depicts my motor setup. Here's the link, but the video isn't in English. The drawing is great though!
 

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MaxHeadRoom

Joined Jul 18, 2013
24,980
As post #11, I also expected to see two values between start and run winding for that size of motor, normally they are only the same up to around 1/2 HP.
 

Thread Starter

elissquires

Joined Dec 26, 2021
26
All right. I've tested as you suggested. Long story short, the two windings are electrically identical. I connected Winding 1 in series with a 12v battery, and a DC motor pulling 11.3A. Voltage drop was 8.2V across the winding. Then connected Winding 2 in the same way. Voltage drop across this winding was also 8.2V as well. Used 2 x DMMs simultaneously, one (Fluke) across each winding, and a generic in series measuring the amperage. Does that mean that either winding can be used as the starting and/or running winding as per the "single phase dual capacitance" schematic above? Thanks.
 

MaxHeadRoom

Joined Jul 18, 2013
24,980
It does sound as though they are identical, and if so, either could be used for start winding.
Usually this is only found in PSC < 1/2Hp motors.
 
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