Start and Run Capacitors on Old Lathe Motor

Thread Starter

ewood

Joined Sep 28, 2013
4
Hello All,

I just bought a 1984 model Tida 1336 Lathe. Both of the original capacitors had been removed from the 1.5 hp, single phase, 4 pole, 110 vac motor. There are only two wires running into the capacitor box. The data plate says 2 x 300mfd caps. The electrical schematic shows both start and run capacitors, but no mfd values. Can the run capacitor have the same value as the start capacitor? Would they be connected in parallel or series? Thanks for any help.
 

MaxHeadRoom

Joined Jul 18, 2013
30,881
Unusual to get that high a value in both start and run?
The will be connected separately and the start cap will go to the centrifugal switch and the other to stay in circuit with the start winding.
If you can get run caps in that high a value then obtain run type for each.
Max.
 

Thread Starter

ewood

Joined Sep 28, 2013
4
Thanks Max. Grainger doesn't show anything over 80 mfd in a run capacitor. Should there be more than two wires into/out of the capacitor box? Someone has tried to figure this out for the previous owner, so I'm not starting in virgin territory.
 

MaxHeadRoom

Joined Jul 18, 2013
30,881
Normally you would have at least three wires into the motor with two caps, this is not two speed motor is it? Or 30.0μf by any chance?
Max.
 

#12

Joined Nov 30, 2010
18,224
You have contradictory information, 2 caps and 2 wires. Can you look up the number for the motor and seek help from the motor manufacturer?

A vague guess from me would be about 15 uf and 85 uf. However, these things change over the years as higher efficiency motors are being produced and sold since 1984.
 

Thread Starter

ewood

Joined Sep 28, 2013
4
No, its 300 mfd (x 2). I've pulled the motor off the lathe now to get a better look. There are 4 black wires and two red wires that run into the motor case. The red ones go through the centrifugal switch, and the black ones are paired with a permanent bridge. There's no continuity across the unconnected black pairs. I thought those went to the coils, but I'm learning as I go. Single speed, 1740 rpm. Not sure yet if its reversible, I think that's done mechanically.
 

Thread Starter

ewood

Joined Sep 28, 2013
4
Sorry, what I called a bridge is just a brass connector. The two wires in the cap box made me think they were in parallel. Its a Sheng Seng, or something like that. The lathe maker went out of business 20 years ago, don't know about the motor co. I'll dig for a broken wire tomorrow.
 
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