parasitic draw on a 420 - part 2

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Paul Buhler
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parasitic draw on a 420 - part 2

Post by Paul Buhler » Thu Mar 23, 2017 1:49 pm

Hi,

Time to teach you about the voltmeter part, then. You have two: DC and AC. Use the DC one on the old 420.

You have a 6.3 volt nominal system there. That means neither charging or discharging. The only major load you have is the starter. That will pull the battery down to around 4.5 volts. Charging will see about 6.8 volts or so.

All you need to do is hang the positive lead onto ground and poke at things with the negative lead and see what is where. Of course, with it off, there should be nothing anywhere beyond the input side of the ILDB switch.

You can save the AC voltmeter for working on house and shop wiring. There will be no AC anywhere in a generator system. You use the AC side sometimes on alternator systems because when they have issues, there is usually some unwanted AC riding on top of the DC. But, that is not on a 420.

Stan
Thanks Stan. Been poking around a bit. Only blew up one cheap multimeter. They do not like high amperage. :D
Paul Buhler
Killington, VT
420c 5 roll with 62 blade, FOPS, and Gearmatic 8a winch

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Stan Disbrow
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Post by Stan Disbrow » Fri Mar 24, 2017 5:11 am

Hi,

Also...gotta watch using the ohmmeter / continuity on live circuits....they do not like that, either!

Stan
There's No Such Thing As A Cheap Crawler!

Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)

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Paul Buhler
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Post by Paul Buhler » Thu Apr 06, 2017 10:58 am

Hi
Replaced the voltage regulator. The old one was full of water and corroded. Swapped wire for wire one at a time cleaning and greasing the connectors double checking with the wiring diagram during the process. Now my battery holds a charge while connected and the ignition is off. Parasitic drain is gone - at least I think it is.

Next problem.
Generator is not charging. I took a jumper from F terminal to ground (the frame), and no change showed at the amp meter, needle stayed centered. Took positive ground lead off the battery while the tractor was running at a fast idle and the machine died, so I suspect a generator issue. Generator was professionally rebuilt a year or so ago.

It is raining hard right now, but I plan on re-checking all the wire connections at the generator, and clean and retighten the mounting bolt and belt tensioner - to make sure the generator is grounded to the machine.
If this does not work I suspect the brushes may be sticking, or....?

My next steps would be to loosen/remove the fan belt, isolate the generator and try to get it to run as a motor. If it does not run like a motor, I will take it off the machine and dig deeper.

I would like to hear some thoughts. Thanks Paul
Paul Buhler
Killington, VT
420c 5 roll with 62 blade, FOPS, and Gearmatic 8a winch

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1954cooter
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Post by 1954cooter » Thu Apr 06, 2017 1:25 pm

You could try polarizing your generator.

Cooter

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Paul Buhler
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Post by Paul Buhler » Thu Apr 06, 2017 4:21 pm

Cooter: Oops did that. Forget to mention it. I went back to an old post on this subject and re- read the thoughts of others.
I have noticed that my crawler is running smoother at low speeds
than I remember. Love the rythmic loping of a good running engine at any speed. Now to connect the final dots. Paul
Paul Buhler
Killington, VT
420c 5 roll with 62 blade, FOPS, and Gearmatic 8a winch

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Paul Buhler
350 crawler
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Posts: 991
Joined: Wed May 21, 2008 6:25 pm
Location: Killington, VT

Post by Paul Buhler » Wed Apr 12, 2017 5:13 pm

Update: Did a "motor test" on generator, nothing, which confirmed the separate voltage meters zero reading at the field and armature posts. Took the generator to a local rebuild shop, and he verified a bad generator.

It turned out that as I suspected by now, there was a break/short in the field coil. He replaced it and viola, tested out as working. He polarized it and I reinstalled it, fired up the dozer and yay, the amp meter showed a charging situation as it should. Ran the dozer for a while, shut it down and the battery tender showed a full charge in the battery within minutes.

I had looked online for a replacement field coil, but when I got my local estimate to fix, it was cheap enough and a same day turn-around so I went that route.
I do have an old slightly damaged generator that I may rebuild just to have a spare and to learn something new.

as mentioned earlier, the dozer is idling smoother than ever, so something else got fixed in the process of troubleshooting the parasitic draw.

Found these manuals:
generator service manual:

http://www.bowersflybaby.com/tech/delco ... erator.pdf

and this parts manual. My gen # is 1101859:

http://www.numeralkod.com/cross/archive ... t%2004.pdf

regulator manuals
http://www.ruiter.ca/mc/info/PDFs/1R-115.pdf
http://www.ruiter.ca/mc/info/PDFs/1R-116.pdf
http://www.ruiter.ca/mc/info/PDFs/1R-118.pdf


Thanks again for the comments and help working through this. Paul
Paul Buhler
Killington, VT
420c 5 roll with 62 blade, FOPS, and Gearmatic 8a winch

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