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Re-winding solenoids.

Discussion in 'Electronic Repair' started by Jeffrey Angus, Oct 16, 2011.

  1. You're right. I don't. Because my original question was
    in regards to ampere turns and rewinding a solenoid for
    a different operating voltage.

    Because so far, with one notable exception, everyone has
    insisted on coming up with some Rube Goldberg solution or
    accusing me of trying to murder widows and orphans.

  2. Since you seem to be so good at divination....Pray tell me just
    exactly how a three-pole double throw transfer switch can connect
    the emergency power to the line rather than the load.

    The ONLY thing this switch can do if the solenoid fails is to NOT
    actuate the switch from one position the other.

    But I'm sure you have a reasonable explanation on how that can
    not be the case here.

  3. Jamie

    Jamie Guest

    I must say, you are an idiot!

    How is the device itself any less dangerous than using an alternate to
    operate it?

  4. Jamie

    Jamie Guest

    You can speculate all you want. You sound like an attorney looking for
    work or closely related to one.

    If you read the blog, you would see what he is using if for, and if
    he really wants you to know, I am sure he'll refresh your memory.

  5. I suppose. The solenoid coil listed is for the series 940. It
    is also used for several other series. Specifically, in my case,
    the Series 386 manual transfer switch.

    And in case you missed it earlier, here is the link for an eBay
    auction showing picturs of the transfer switch contactor.

    A similar model. 2-pole 120 VAC rather than 3-pole 480 VAC.

    And if you go to the website and look up the replacement
    part numbers for the model 300 or 386, it directs you to the coil
    marked as being for the series 940.

    This is the coil itself from ASCO.

    But again, you're making all sorts of asumption looking to find
    fault. You've done nothing what so ever to answer the question
    on rewinding a solenoid to operate at 240 volts rather than 480.

  6. Really? Explain how you came to that conclusion.

    I started with known measured numbers. Worked backwards with
    a calculator to get the unknown. From there I went forward
    towards what I thought was correct.

    Then asked if what I was doing sounded right. I.e. basing the
    requirements on ampere turns.

    I even went so far as to include the calculator I used to
    determine the number turns based on the physical size, DC
    resistance and measured inductance.

    So, and unfortunately VERY typical of Usenet, I've had to put
    up with unfounded personal attacks and a whole plethora of
    "How you should do anything except what you want to."

  7. The pulse is mechanically derived.
    The small control relay energizes the solenoid. When the solenoid
    causes the transfer switch to actuate, the auxiliary contacts
    open the solenoid connection.

  8. josephkk

    josephkk Guest

    Just for grins, Jeff 1.0 have you tried spice models of the rectifier
    solenoid at 480 and 240? It may help you see something you may have
    missed. BTW i expect you will replace the bridge with one appropriated
    rated for the solenoid?

  9. It hadn't occurred to me to do that. It's pretty much of a static
    operation. You apply power, it pulls up on the armature. When the
    mechanism changes position, an auxiliary switch disconnects the
    The original bridge was dealing with 480 vac @ 5.2 amps. The new
    coil will present a load of about 4 amps @ 240 vac. It's not an

  10. josephkk

    josephkk Guest

    I expect you can learn interesting things looking at the current waveforms
    in the various configurations.
    That does not make sense for the ampere-turns argument. The number of
    turns drops dramatically thus the current must increase accordingly.
  11. 480v coil 2500 turns @ 4.8 amps
    240 coil 2000 turns @ 6.0 amps

  12. josephkk

    josephkk Guest

    Not as bad of a turns drop as thought. The new numbers make sense.

  13. A follow up to this exercise.

    Using 1/16" PVC for the ends and schedule 40 1/2" PVC
    for the core, I wound 2000 turns of #28 wire on the
    form and put things together to test them.

    It works with 240 VAC across the bridge rectifier now.

    And yes, the coil heats up. It's trying to dissipate
    1440 watts. (240 VAC @ 6 amps)

    The contacts on the transfer switch disconnect the
    solenoid coil from power as soon as it starts to move.
    Inertia carries it through the sequence.

  14. There is that. See below...
    See, now this is where everyone got upset over nothing.

    This whole exercise was to see _IF_ I could correctly wind a
    replacement solenoid for 240 V rather than the original 480 V.

    Now that I've satisfied my curiosity, I'm going to sell it in
    it's original format (480 v 3-phase) as THAT is where it's value

  15. Fear not fearless leader, I'll remember to cut you in.

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