Alternator problem

[cowsrus]

Does anyone know how to ck an alternator to see if its working. I have an IH 886 tractor and i've changed the alternater out twice now and i still don't have any output voltage. Shouldn't you have voltage at the output lug if you disconnect it and ck with a voltmeter? Mine doesn't and i have 12v at both of the plug-in terminals. I'm stumped! Help. It cks 12v hooked up but doesn't seem to change and i can't tell if its working or not/

 

[DieselPower]

You should never run a alternator with the B+ wire unhooked from it. Is this alternator internally or externally regulated? If it's internally regulated it will not produce any power if the B+ is not hooked up. A alternator can not produce power unless it has power to run off of. The rotor has to have power to produce a magnetic field, no magnetic field, no power produced in the stator assembly.

 

[bobzap]

I usually put a voltmeter across the battery and watch it awhile to see how many volts it is putting out, usually around 14 volts.

 

[Redneck in training]

When engine not running the battery should have about 12V. When engine running it should have about 14 V. In example your headlamps should go brighter.

 

[SPYDERLK]

Are you putting in new alternators or at least ones youare sure work? How many different wire connection points to the alternator? With a functioning alternator the battery voltage will rise above 13V quickly after starting the engine.
larry

 

[cowsrus]

I have 12v at both #1 and #2 terminals. When i ck the voltage i get 12.47 v and when i start the tractor the voltage never rises. i got both alternators at the auto parts stores.
i did figure out that you don't get any voltage when u unhook the main terminal going to the battery, so that helps a little, but i can't figure out why the voltage never goes up even when i turn on the lights and a/c.

 

[Soundguy]

If this is a standard delco 10/12 SI alternator, you need the charge lug hooked to the battery ( thru meter.. etc.. ), the #2 line can be looped to the charge lug. The #1 line can be hooked thru a 194 marker lamp to the switched side of the ignition switch.

If it is a later model.. like a CS130.. it needs 15-45 ohms of resistance in the #1 line.

soundguy

 

[cowsrus]

The #1 terminal line is switched though the switch and the #2 terminal line has 12v present with the sw on or off. i also have 12v at the output lug terminal with the tractor not running. But the voltage doesn't go up any with the tractor running and thats what makes me think its still not working. Most alternators run over 13v and this one doesn't. Do you think the fact that its an alternator originally intended for a chevy truck would account for that?

 

[Matt_Jr]

Do you think the fact that its an alternator originally intended for a chevy truck would account for that?

What do you mean by that?

Anyone have a wiring diagram they can post?

 

[cowsrus]

It's a delco alternator that i bought at the auto parts store instead of buying it from the IH dealer. Shouldn't be any difference unless they were rated at different amps. But i wouldn't think that would be a big problem because a tractor doesn't use any more elec than a car.

 

[Soundguy]

there are probably more generic chevy alternators retrofit onto machines today ( usually delco 10si and 12 si alternators) and heavy equipment and tractors than oem alternators and generators.. probabble by a 2:1 ratio... or more...

if the al is spinning 400+ rpm, has switched power on 1, and power on 2 and charge lug, and don't make bat voltage come up.. take it in for a free check at yer local auto parts store.

soundguy

 

[Hooked_on_HP]

A simple way to see if the alternator is putting out is, with the engine running put a wrench close to the back of the alternator. If the wrench gets drawn to the alternator it is working if it doesn't its not.
Bill

 

[Leejohn]

If you have a charge lite and you have that pluged in, the bulb has to be good. If bulb is not being used just run a jumper between the 2 little spade terminal. It well not charge until rpm comes up 800 to 1500rpm, if you have this type. If you ran without Bat. terminal, like you said, then you might need a new reg and ref. in it

 

[Soundguy]

Most of those delco will turn on at 350-450 rpms with the #1 wire hooked up. it's only the crappy 1-wire hack jobs that need the high rpm to turn on.

as for the magnetics trick..

the best 'simple' test is the vom.. it just don't lie.

ditto on running an alt with no bat hooked up.. it can smoke them fast..

soundguy

 

[cowsrus]

The tractor has a meter on the console and it only reads about 12v and never goes up. When you turn on the a/c and the lights it never seems to go much above 12v and thats what makes me think the sob isn't working. It's a new rebuilt and i just exchanged it for one that they tested before and said was good. The confusing part is that i check the voltage at the output lug, i get 12v with the tractor off and then when i start the tractor, the voltage doesn't change. Should a regular ampmeter (the clamp on type) work if i clamped it around the output wire, I'm not sure if it works on dc voltage or not. Guess i could try it and see?

 

[Soundguy]

a multimeter volt meter is what you need... big difference inthe display.. 12v vs 14v

heck.. you can test it on a drill press with a battery and jumper wires..

bat + to charge lug and #2, bat - to alt frame.. use a jumper wire and 194 lamp inline with #1 and bat +. hook that up.. lamp should come on.. start up the press with it coupled to the alt and the lamp should go out and you should see 14v on the battery.

soundguy

 

[David-Davies]

If you put a load on the system, and the voltage stays the same, then your alt. is probably working. Your batery could have a short, witch will not let the voltage get above 12v. Try a differnt battery.

 

[SPYDERLK]

Good point! Another method that would verify this possible camouflaged funtion would be a clamp on meter. You need to know which way the electricity is going. There are some inexpensive clamp on gauges that just screw clamp around the battery lead. These will tell you which way the current is going with a sensitivity of ~ 2A. You can even start the engine with them in place. Altho it pegs the meter it doesnt hurt the gauge. After the start the needle should go to the other side of zero and stay there as you turn on electric loads. If so get a new battery - the one you have has a low working voltage and is going to constantly need water due to the high charge rate the alt will provide because it senses it to be needed. The continuous high charge will make the alt run hot and shorten its life. Does your alt get hot in just a few minutes?
larry

 

[Soundguy]

center 0 ammeter will do the job.... just put it in the power feed line from the bat / solenoid.. not the line to the starter.. thus no meter pegging..

soundguy

 

[mitch becton]

delco 10si/12si had two wiring configurations one allowed the unit to work with only a hot/battery wire hooked to the in-put post if you have the 3 wire hook up alt it will be hard to make work i would check with the parts store to see if they know what they sold you should not use a plug in wiring harness if you have to one wire self exciting alternator this also applies to the cs130 alternator the most important factor to these working is what is called a self exciting regulator. And for what it is worth over the past 20 years i have sold several thousand of these self exciting units for farm equipment replacement for the replacement of generators with lowout put and the high cost of rebuilding generators. hope this helps.

mitch becton