electical question

rosedale123 · Sep 21, 2013

when i unhook the battery the tractor quits - is that correct? It has a 12 volt conversion using an alternator ( 3 wires) .From the spade connector one wire (#2) goes to the battery lug on the alternator. the other wire on the spade conector (#1) goes to the igniton swith. the battery lug on the alt ( I used 10 gage)goe to one side of the ammeter. the other side of the ammeter goes to the battery.

the ammeter needle does not "flinch" when the ignition is turned on and does not move when when the tractor is running. when running the battery voltage is 12.45. the battery voltage a the battery lug on the alternator is 12.45/

Would you say the alternator is not working???

JDemaris · Sep 21, 2013

A fully charged battery with NO alternator charge is 12.7 volts. If the alternator is working, the voltage should be 13.8 to 14.2 volts. So yes, your alternator is not charging. You can bypass the voltage regulator if you want by sticking a pin in the back of the alternator into the "full field" port. If it starts to charge, it means the regulator is bad (A $12 item).

rosedale123 · Sep 21, 2013

so is that jumping #1 across to #2 to seeif it charges?

by the way you wouldn"t have been in the Air Force? I knew a Demaris in The AF.

Bob M · Sep 21, 2013

Nope! Behind the D-shaped hole in the rear of the alternator there's a metal tab (photo). Use a small screwdriver, or similar to ground the tab to the side of the hole. This will bypass the regulator.

If the alternator is good should see 14 - 15+ volts at the battery with the engine at speed and the regulator bypassed.

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Also it sounds like your ammeter is stuck (it should show -3 amps or so when you turn on the ignition.) Test by bringing a small magnet to the face of the gage and moving it around. The gage hand should move freely away from center in both directions as you move the magnet.

ken house · Sep 21, 2013

does the battery run down? if no what is the problem?

some one else will have to chime in, but, i think that if you remove the battery, on an alternator system, the engine will quit. maybe, not so with generator.

old · Sep 21, 2013

#1 doing that is not a safe thing to do because the alternator sees a dead battery and goes to max charge which in turn burns out the VR and that in turn makes itr put out 90 pl;us volts at 35 plus amps and if you got between the + cable and ground it can and will fry you as in your DEAD.
Only way to check and alternator is with a volt meter. Be safe not DEAD or hurt.
With it not running you should have around 12.3 volts on the battery with it running 13-14 volts.
NEVER pull the battery cable to check an alternator it can cause you and the tractor big problems

Janicholson · Sep 21, 2013

Please don"t unhook the battery when running. The alternator (when working) becomes unregulated and can fry things with high voltage. (even fry You)
It is a test with a generator, not an alternator.
If full fielding it does nothing, the alternator is not working. If it does charge (assumes a good amp meter, or reading of 14 volts or so on the battery) the regulator in the alt may be bad.
You state that the #1 terminal is connected to ignition. It should be passing through a marker bulb (NOT LED) on its way to the key. Or a 10 ohm resistor, or a diode with the band toward the alternator. Without this device in the wire (series) the engine will continue to run even with the key shut off. This light/resistor/diode device acts like an idiot light, and must be there. Jim

souNdguy · Sep 21, 2013

in addition to the good info here.

I'd check the wiring onthe ignition switch.

for net charge / discharge.. ignition wire needs to be on the side of the ammeter as the charge device and all other loads.. with battery alone on the other side.

Owen Aaland · Sep 23, 2013

To check the wiring to the alternator you should have battery voltage at the battery stud on the alternator and also at the #2 terminal all the time. Terminal #1 should have voltage only when the switch is on. The amount of voltage is not too important but should be at least 6 volts or more to insure the alternator will start to charge at lower rpms.

As others have posted there should be some type of resistance between the switch and the #1 terminal. If not that circuit also becomes a charging circuit. You can overload the diode trio on the alternator when that happens. They are only designed to provide power for the regulator. If too large a portion of the charging amperage passes through them they will have a short life.

electical question

rosedale123

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JDemaris

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rosedale123

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Bob M

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ken house

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old

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Janicholson

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souNdguy

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Owen Aaland

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