Start and Run Capacitors on Old Lathe Motor

Discussion in 'General Electronics Chat' started by ewood, Sep 28, 2013.

  1. ewood

    Thread Starter New Member

    Sep 28, 2013
    4
    1
    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.
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,548
    2,373
    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.
     
  3. ewood

    Thread Starter New Member

    Sep 28, 2013
    4
    1
    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.
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,548
    2,373
    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.
     
  5. #12

    Expert

    Nov 30, 2010
    16,298
    6,810
    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.
     
  6. ewood

    Thread Starter New Member

    Sep 28, 2013
    4
    1
    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.
     
  7. #12

    Expert

    Nov 30, 2010
    16,298
    6,810
    What kind of a bridge? The obvious answer is, "bridge rectifier" but that is unreasonable for an induction motor.
     
  8. ewood

    Thread Starter New Member

    Sep 28, 2013
    4
    1
    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.
     
    #12 likes this.
  9. shortbus

    AAC Fanatic!

    Sep 30, 2009
    4,013
    1,531
    while not for your exact model, here is a Tida operators manual, that may help you. Many of these lathes are the same , just different name.

    http://wttool.mywowbb.com/forum9/336.html This is the source, it was too big to upload here.
     
    Metalmann likes this.
Loading...