testing generator
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=36093
Printed Date: 26 Apr 2025 at 6:58am
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Topic: testing generator
Posted By: Bill_MN
Subject: testing generator
Date Posted: 24 Aug 2011 at 10:24pm
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Battery keeps going dead on my WD, it might be the battery but I would also like to check the condition of the generator system (Two-brush with VR). Where do I put the multimeter points to see if the generator is charging the battery, And how many volts should I have? Is there another method for testing the genny?
------------- 1951 WD #78283, 1918 Case 28x50 Thresher #76738, Case Centennial B 2x16 Plow |
Replies:
Posted By: Tedin NE-OH
Date Posted: 24 Aug 2011 at 10:31pm
| Watch the amp meter. |
Posted By: Orange Blood
Date Posted: 24 Aug 2011 at 10:33pm
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Well the correct way to verify the generator is to use a current meter, just like the oem one on the tractor, or at the very least a current probe. What I would do with a volt meter is measure the battery voltage with the engine running vs. stopped. If the voltage is higher running then stopped, the genny is at least trying to work, the question is how much higher. Each cell of a lead acid battery typically runs about 2.2 volts, so a fully charged 6 volt will run around 6-1/2 volts, and a 12 volt batt will run around 13.6 volts. Charging voltage should be just above the respective voltage to charge the battery, anthing less than the above voltage will discharge the battery. I hope this is enough to get you started. ------------- Still in use: HD7 WC C CA WD 2-WD45 WD45LP WD45D D14 3-D17 D17LP 2-D19D D19LP 190XTD 190XTLP 720 D21 220 7020 7030 7040 7045 3-7060 Projects: 3-U UC 2-G 2-B 2-C CA 7-WC RC WDLP WF D14 D21 210 7045 N7 |
Posted By: stray
Date Posted: 25 Aug 2011 at 3:55am
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Using a volt meter, first make sure the battery is charged good, and then let the static charge dissipate for a few minutes. Then check the battery voltage with the engine off. Start the tractor and let it run 3 to 5 minutes at about ½ throttle, then check the battery voltage with the tractor running. Compare to the 2 voltage readings if the non running is 12 volt then the running should be 1.5 to 2.5 volts higher, on a 6 volt the reading will be .75 to 1 volts higher. A generator take longer to get the voltage up in the battery than an alternator you don’t need to let it run for a few minutes when using an alternator. Also the belt tension is more critical on a generator then on an alternator. If the readings aren’t right be sure to take both the generator and regulator to the rebuilders or part store to have check. ------------- 1969 190XT series 3 |
Posted By: Dusty MI
Date Posted: 25 Aug 2011 at 7:27am
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An old simple way. Take the belt off of it. Take the cover off the cutoff and hold the contacts closed, the generator should run like an electric motor but much slower. Dusty ------------- 917 H, '48 G, '65 D-10 series III "Allis Express" |
Posted By: DonDittmar
Date Posted: 25 Aug 2011 at 8:35am
------------- Experience is a fancy name for past mistakes. "Great moments are born from great opportunity" 1968 D15D,1962 D19D Also 1965 Cub Loboy and 1958 JD 720 Diesel Pony Start |
Dusty MI wrote:Posted By: Coke-in-MN
Date Posted: 25 Aug 2011 at 10:26am
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Here is a site on generators and regulators and tests and repair .. all the info you may need . Is for Chev but covers all Delco / AC systems .
http://chevy.oldcarmanualproject.com/electrical/49dr324/index.htm - http://chevy.oldcarmanualproject.com/electrical/49dr324/index.htm ------------- Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something. "Challenges are what make life interesting; overcoming them is what makes life meaningful." |
Posted By: Bill_MN
Date Posted: 25 Aug 2011 at 10:09pm
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Thanks, I should have enough info to get started. As I said before this is a two brush generator with a voltage regulator (VR), not a cutout system.
------------- 1951 WD #78283, 1918 Case 28x50 Thresher #76738, Case Centennial B 2x16 Plow |
Posted By: DonDittmar
Date Posted: 26 Aug 2011 at 6:02am
An alternator doesnt need a cutout beacuse it rectifies to DC output by sending the current through a diode trio and heat sink(known as the rectifier). I diode is an electrical check valve which will let current out of the alt, but wont allow it in.
Take an alt apart and change the diode trio and you can make it charge + ground systems. ------------- Experience is a fancy name for past mistakes. "Great moments are born from great opportunity" 1968 D15D,1962 D19D Also 1965 Cub Loboy and 1958 JD 720 Diesel Pony Start |
Posted By: Steve in NJ
Date Posted: 26 Aug 2011 at 7:21am
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Boy these guys are gettin' good! Makes an electrical guy like myself wanna cry.... LOL!
mailto:Steve@B&B - Steve@B&B
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Posted By: Gerald J.
Date Posted: 28 Aug 2011 at 6:54pm
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Yup, steve they even like the ammeter... In theory the fully charged starting battery floats at 2.35 volts per cell, so 7.1 volts on a 6 volt and 14.2 on a 12 volt. Generator regulators don't hold the voltage that precisely though. Voltage rising at the battery terminals is best tested by digging the meter prods into the bettery posts themselves because an open connection can show adequate voltage for charging but if the battery posts are corroded (and they need cleaning nearly twice a year on a 6 volt to keep it starting and charging) the battery won't be seeing that charging voltage or taking a charge. Gerald J. |