Ford Question

[WV Hillbilly]

Not a car , a tractor . Has a six volt generator . Repair manual says to disconnect wire at
generator & connect ampmeter leads to generator terminal & disconnected wire to take an
amperage reading off the generator . I know the correct terminal & wire to use to do this .
Here's my question . I have a clamp on meter that surrounds a wire to take an amperage
reading . Instead of disconnecting the wire from the generator can I just use the clamp on
meter to take the amp reading ? Thanks

 

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[SgtSki in MI]

You could try I suppose. What model/year tractor is it and what's the problem with it?

-SgtSki

 

[WV Hillbilly]

It's an older ford 800 . Not sure what year model . Charging system not keeping the battery
charged . I did try it & didn't get a reading . I worked for years as an electrician & used this type
of meter on house type voltage & amperage . Just wasn't sure if it would work correctly using it
on the tractor . Thanks

By the way tractor has an ampmeter which I believe is broken . The meter on the tractor
is round & has a 0 in the center with 0 to - 30 on the left and 0 to + 30 on the right . The meter
stays bottomed out to the left all the time , running or not . I think it should read 0 when not running
and with the switch off .

According to the manual I can install a jumper wire on certain terminals & bypass the voltage
regulater to just check the generator . I have a meter that I could disconnect the wire & check as
the manual suggests but the meter is only rated to run 10 amps through & the generator should
put out 20 amps if working correctly .

 

[corklabus]

First check the battery for short circuit and fluid level. Then load check the battery. If that checks out, just have the generator rebuilt. You may also be able to replace the generator brushes yourself. More than likely the actual problem will turn out to be the voltage regulator, which isn't an expensive replacement.

 

[flip]

A quick check on for generators is to ground the field terminal to the frame with tractor running, if amps raise generator is good. If that checks out voltage reg. is probably bad .

 

[Starbuck]

Hillbilly,
Is the clamp meter rated for DC or AC? If it is an AC clamp meter you will not get an accurate reading of DC amps. You need to check the specs for the meter there are a lot of them that have AC only amp readings but will have lead and dial settings that can read DC Volts. If you don't have an amp meter that can read that high of an output in amps set the meter to volts DC and compare the reading across the battery if the generator is charging you should read about 7.5 to 8.5 volts with the engine running at about 1,500 rpm's. I have seen the actual amp meter gauge you are talking about go bad and cause the system to not charge. The next test you should do if you do not see the 7.5 to 8.5 volts at the battery terminal move the black lead to the generator post and see if the generator post is showing 7 volts or higher you have a bad gauge if it is no change from the reading at the battery then the generator is probably at fault. - Starbuck

 

[WV Hillbilly]

The clamp on meter has both ac & dc settings . Now that I think about it I'm not sure if it
will read dc amps or not . I know that it reads ac & dc voltage but not sure now about dc amps .
I'll check tomorrow as the meter is out in my shop . I'll replace the ampmeter on the tractor as
I already have a new one . I'll also try the suggestions mentioned . Thanks All

 

[SgtSki in MI]

I'd go along with the voltage regulator too, and/or the brushes on the generator.

I don't know if this is a factor or not, but is it a positive-grounded electrical system? I'm asking because it's a 6-volt system and a lot of older cars and trucks were positive-ground so maybe the same goes for tractors. Those of us who tinker with automotive electrical systems get set in our ways with the more common negative-ground. maybe someone was thinking that way and hooked something up bass-ackwards on a positive-grounded electrical system.....just a thought.

-SgtSki

 

[WV Hillbilly]

Hi Folks
It is a positive ground system . It also has a brand new battery that I have fully charged with a
battery charger from time to time . I went visiting today & didn't get a chance to do anything
with the tractor . Didn't even look at the meter to see if it would read dc amps . Maybe tomorrow .
I'll update after I try a few things in case anyone is interested . Thanks All

By the way my manual says to check the armature with a " growler " to check for shorts . I am
going by memory at the moment so bear with me if the " growler " test isn't for a shorted
armature . Naturally I don't have a " growler " so can I perform the same test using meter readings ?

 

[SgtSki in MI]

I havent seen a growler in years. But yes, it's used to test the continuity of an armature. It's kind of lengthy to explain how one works, but I found a link that explains it: It's out of a miltary TM for a 2 1/2 yd Loader.

http://www.tpub.com/content/constructionloader/TM-5-3805-262-34/css/TM-5-3805-262-34_703.htm

I don't know how to check an armature otherwise. Another thing is that the armature (or commutator) is worn down smooth and shorting. You can use an armature saw and cut the insulation back so there are grooves between the lobes on the armature, but if you have to resort to doing that you're better off getting a rebuilt or a known-good used generator.

You can always do what I do and throw money at it. A rebuilt generator for your tractor runs from 120-140 bucks and a voltage regulator's about 40 bucks. A generator rebuild kit's about 15 bucks. That's usually my unwise M.O......Troubleshooting by component replacement.

_SgtSki

 

[flip]

http://www.ytmag.com/articles/artint129.htm this might help.

 

[WV Hillbilly]

http://www.ytmag.com/articles/artint129.htm this might help.

Thanks a lot , great link .

 

[WV Hillbilly]

Re: Ford Question / another one

I bought this tractor off my father-in-law & a few years ago he had the engine compleatly rebuilt . It runs great . However all the wiring has been unhooked at least once . I mentioned before that it is a postive ground system & that I thought the ampmeter was bad . I replaced the ampmeter with a new one & I noticed the posts on the back of the ampmeter were marked + & - . I know which wire I removed from which post but don't know if the person before me did . This positive ground system has me a little confused . I have a repair manual with a wiring diagram & it shows all the wires & where they go , to & from . The diagram has a circle that denotes the ampmeter but it doesn't show the posts as + or - . One wire that goes to the ampmeter runs straight from the battery side of the starter solenoid & the other wire goes to a terminal block . Since it's a positive ground the battery cable that goes to the starter solenoid is connected to the - terminal on the battery . Would that mean that the wire going from the starter solenoid to the ampmeter would go to the - post on the back of the ampmeter ?
Also I was told yesterday that a battery could be reverse charged & when charging a battery for a positive ground system the leads on the battery charger needs to be reversed . Instead of clamping the red clamp on the charger on the + battery terminal it needs to be on the - battery terminal . Anyone know anything about all this positive ground crap ? Thanks

 

[corklabus]

This one is a bit beyond me. What I would do on the ammeter is turn on the key and touch the wires to the terminals very briefly and watch what the guage does. If it shows the current available correctly, that's where the wires go. If they are reversed the guage will operate backwards.
Just the other day I was researching batteries. It IS possible for a battery to reverse its' polarity by being charged backwards. The solution to this was to totally discharge the battery, then recharge it properly and it supposedly will change its' polarity back to what it is supposed to be. Keep in mind that it was printed on the internet, so it must be true. At any rate be careful of sparks. 6 volts seem to be more prone to charging fume explosions.

 

[Starbuck]

Hillbilly,
A lot of old cars and tractors used positive grounds. The positive ground works just like the negative ground in modern vehicles. The ammeter should have the + side of the gauge hooked to the plus side of the battery and the - to the minus side. The current will flow from the generator through the gauge and back to the battery. - Starbuck

 

[rmptr]

Hillbilly, an old for tractor just doesn't use much electricity.
With a new battery, fully charged, you could probably run it for days without a need to charge it.
Unless you got David Allen Coe blasting with a couple thousand watts of power as you till the field!

Quick generator check... does it have lights? turn on lights and start it. If lights get dim = no charge.
if they brighten with increased rpm = charging.
I wouldn't worry about the ammeter. They're usually broke!

It would be difficult to find a growler, let alone someone who would sit down and use it for you.
I've only seen one, in my life!

Your res test meter won't read amps unless inserted inline. clamp on probably won't work for DC amps.

Pretty easy to check generator brushes.
Eyeball the commutator when you pull em. If grooved badly, just replace generator.

Check for pitted contacts in regulator. NOT hi-tech, you can file 'em if arc'ed or pitted.
Smell inside of cover when first opened. Will smell burned, if it its.

rmptr