Help replacing a gate opener start capacitor

Discussion in 'General Electronics Chat' started by Texaco5, Feb 9, 2014.

  1. Texaco5

    Thread Starter New Member

    Feb 9, 2014
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    0
    I have an Edko electric gate that has a Mepco Electra start capacitor. The gate motor is a single phase 115 VAC with a 24 VDC control. I think Edko was bought by Chamberlain based on what I have read online so parts info is scarce.

    The open and close relays are both connected to the motor via a capacitor. The capacitor has a label with the following markings:

    Mepco Electra
    3535B5A0072A330B4
    35F1663BA8
    330 VAC 60HZ 3628726

    It has 4 spade connectors on the end and measures 4.25" long and 1.75" diameter.

    Looks like it was manufactured in 1988 (so its done well to survive this long) but I haven't been able to find a good cross reference that helps me translate the old Mepco Electra part numbers into something current.

    Unfortunately the wiring diagram simply shows 'Motor Capacitor' without any spec/performance information. Can anyone help with a recommendation of what I should buy to replace it?

    Thanks in advance
     
  2. GopherT

    AAC Fanatic!

    Nov 23, 2012
    6,043
    3,807
    Could you post a photo of the device, the board and the schematic.
     
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
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    It could possibly be both start and run caps in one case?
    Do you know if the motor has a centrifugal switch? You can usually hear them click back as the motor slows down.
    Max.
     
  4. PackratKing

    Well-Known Member

    Jul 13, 2008
    850
    215
    Guessing here... There should be relative info on the motor label, or on the inside of the connection cover...
    educated guess, I worked in a facility that repaired motors for 8 years - a gate-opening motor is likely less than 3/4 HP 1725 rpm... probably hitched to some manner of gear reduction... pully - belt

    Match the voltage of the cap, and 200-350 Mfd unit should fill the bill...
     
  5. #12

    Expert

    Nov 30, 2010
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    "4 spades" means nothing. How many separate electrical terminals?
    I've seen 4 spade connectors on each of 2 electrical terminals.

    Photo, please. Lots of us work with these. Somebody will probably recognize it.
     
    PackratKing likes this.
  6. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Could it be an interference suppression unit?
     
  7. Texaco5

    Thread Starter New Member

    Feb 9, 2014
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    0
    Thanks for the feedback everyone. Sorry #12 - there are two terminals - one terminal connection has a wire that comes from the open relay and goes to the motor and the second has a wire that comes from the close relay and goes to the motor through a separate wire. My sense is that these simply rotate the motor in different directions from the capacitor's initial discharge depending on whether the gate is opening or closing. The motor shaft is also connected (inside the gate box) via a sprocket and chain to a screw thread that has two square nuts on it that slide up and down the screw thread as the motor turns and hit limit micro switches when the gate has reached the fully open or fully closed position. The micro switches then trip and de-energize the relays and the motor stops. A pic of the capacitor is attached.
     
  8. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
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    Ya just gotta hate it when the put the clamp right over the info ya need.
    330 VAC 72-88 MFD Be aware the M in MFD is for MICRO, not MILLI.
    When I was in electronic school they said a 1 farad cap would fill a room!
     
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  9. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Make sure you get a capacitor for AC motor start rated capacitor.
    A local re-winder should have them.
    Max.
     
  10. Texaco5

    Thread Starter New Member

    Feb 9, 2014
    3
    0
    Thanks Bill. Just picked up a new Packard 330 VAC 72-88 MFD start capacitor off Ebay for $9. A lot better option on my bank account than buying a new gate control box given that Edko has been out of business for a while and spares are like hen's teeth to get!
     
  11. #12

    Expert

    Nov 30, 2010
    16,284
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    Now make sure the motor doesn't hang at, "locked rotor" when you try to start it. That cap is called, "dry electrolytic" and it only has a few seconds before it starts overheating and blowing out white smoke. Good enough to start a motor but it self-destructs if the motor is seized up. If that motor doesn't start moving in less than a second, find the real problem that killed the capacitor.
     
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