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lessons learned on voltage regulator

Discussion in 'Mechanic and Repair' started by rbig, Apr 4, 2005.

  1. rbig

    rbig LawnSite Member
    Messages: 112

    Lessons learned substituting a cheap voltage regulator for the OEM one, which the company wants $120 for. You can pick up a number of regulators for approx $20.

    It turns out this is easy, except for one thing. Let me begin by telling the obvious stuff first.

    1. Ya gotta match the voltages, natch. A 12v regulator to a 12v system.

    2. You should match the current carrying capability of the regulator to that of the system rating. 20 amp regulator to a 20 amp alternator.

    3. Now, you're going to have to know whether the system you're working on uses single phase alternators, or whether it uses a 3 phase alternator. Don't assume anything.

    Luckily, most lawn and garden tractor engines have single phase alternators. Many motorcycles and boat engines have 3 phase alternators.

    Then, you have to know for sure which kind of regulator you have (3 phase or single phase). I have no clue on this one, other than to find someone who knows, or go to the manufacturer and ask. If you know exactly what it is used on, that may lead you to answers on this question.

    4. Wires. you can find all combos between 3 and 6 wire regulators.

    The good news is most of the lawn and garden tractor systems which have 4-6 wires can be worked with a 3 wire regulator. What happens is that, typically, there are warning indicator lights that each have a wire going to the regulator. You can simply disconnect these, and all you do is disable the warning light function.

    What the regulator has is two wires going to the alternator coil, and a wire going to the battery. Get those hooked up and you're in business.

    If your regulator has six wires out, that is almost sure to get all your functions operating, if your tractor pigtail is a 6 wire.
  2. CCWKen

    CCWKen LawnSite Member
    Messages: 113

    The 3 & 4 wire regulators are considered "single phase"--Even though the charge coil may have three pairs of coils.

    The 3-wire regulator has two input connections. These are from the alternator coil. The single output connection is for DC. This connection is for charging the battery and operating DC accessories.

    The 4-wire regulator also has two input connections and these connect to the alternator coil like the 3-wire. The other two connections vary by regulator. Both can be DC out or one may be DC out and the other AC out. With the DC/AC out, the DC is used to charge the battery and operate DC accessories, the AC is normally used to power lights.
  3. rbig

    rbig LawnSite Member
    Messages: 112


    The tractor I've been working on uses a six wire regulator, and comes off a single phase alternator.

    Two wires go to the alternator, one to the battery, one is a ground, and two are either sensing from or power leads to the low oil pressure and low battery warning lights.

    You really need to know what's inside the regulators, and what each wire coming out is for. The problem is that for stuff we buy at flea markets, Ebay, etc, that's rarely the case. May not be a good answer for this problem.

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