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wd 45 voltage regulator

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ohio dairy

03-25-2008 06:57:22

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Can someone tell me what the gennerator is supose to put out? I tested it and it was 7 volts.
I am going to replace the wire and buy another regulator. Steve said he has a heavy duty one.(steve your phone # at B&B site didnt work) How is that different from all the other ones i can buy? All the ones i have found have the same part # 574459

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John T

03-25-2008 20:03:03

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 Re: wd 45 voltage regulator in reply to ohio dairy, 03-25-2008 06:57:22  
The open unloaded output of a genny dont really tell yall that much (the faster it turns or the more field current pumped through it the more it generates), its what voltage it can maintain a battery at when its connected to it n spinning at full rated RPM that matters. Depending on the genny n condition of the battery Id expect a battery to measure around 6.3 volts sitting but rise from 6.5 to 7 and a lil over when hooked to a good charging system at RPM. To make her charge at its max possible rate dead grounding the field does that (also if its a 3 brush genny its setting matters) and thats one of my tests below and a way to see if non charging is a Genny or a Voltage Regulation or a light switch problem. problem.

If you work through this in para 5 you can see if the genny or VR or relay or switch etc is at fault. Try easy simple things first like Polarize n insure good grounds and a good belt (see below)


ARE YOU SURE THE AMMETER IS WIRED CORRECT AND WORKS????? If you turn the lights or ignition on (if coil ignition not a mag) when sheís not running, the ammeter should swing over to the - discharge direction, does yours??? Are BOTH the ammeter terminals reading hot battery voltage?? They MUST !!!!! ! Thereís but one wire on the ammeters Supply (from battery/starter) terminal while its other Load terminal wires to the BAT terminal on a Cutout relay or VR PLUS wires to feed loads like lights or ignition, unless where a 4 terminal VR is used where lights n ignition are fed from the LOAD terminal on the VR.

To Polarize the Generator, first temporarily dead ground the Gens Field post to case/frame, then momentarily flash jump a wire from the Cutout Relay or VR's "BAT" terminal over to its GEN (or ARM) terminal and you ought to get a small spark. Same things accomplished by momentarily flash jumping a hot wire (BAT terminal on Cutout Relay or VR or starter post etc) direct to the Gens ARM post to get the spark.


1) For a good working Gen to get to and charge the battery, it has to have a path usually from the Gens ARM post,,,,, ,,,,to and through the Cutout Relay (between its GEN and BAT terminals, regardless if on a VR or Relay),,,,, ,,,up to the Load (NOT to battery) side of the Ammeter,,,,, ,,,to and through the Ammeter,,,,, ,,,,from BAT side of Ammeter to ungrounded battery terminal, often via the starter lug post. Is yours wired that way or equivalent ??? The ammeter should read hot battery voltage on BOTH terminals, does yours??? Even if an ammeter were stuck (but still continuous) as RPM increases the battery voltage should rise from 12.6 to near 14 volts and/or the lights glow brighter (half that on 6 volt systems). Have you tried that in case the ammeter isnít working right?????

2) If the above is so, the BAT terminal on the VR or Cutout Relay MUST ALWAYS READ HOT BATTERY VOLTAGE. Does yours??? If not, the Gen cant get to and charge the battery.

3) The Gen to VR (if it has one) wiring is as follows:

BAT on VR to ammeters load (NOT battery) side

ARM (or GEN) on VR to Gens Armature post.

FLD on VR to Gens Field post.

(L) Load (if you have a 4 wire VR) up to BAT supply input terminal on switch to feed loads like lights and ignition.

WIRING ON CUTOUT RELAYS: They wire BAT side to ammeters Load terminal,,,,, GEN side to gens Armature post. On cutout relay systems, the Gens Field post is wired to the light switch where it gets a dead ground for high charge or a resistive ground for low charge. Therefore, there must be a good connection from the Gens Field post up to the switch PLUS the switch is good and itís well grounded !!!!! !!

4. THE GEN AND VR OR CUTOUT RELAY MUST BE WELL GROUNDED AND THE BELT GOOD N TIGHT. If any doubt, run a ground wire from the grounded battery post or clean solid frame member direct to the Gen and see what happens????? ????? ????? ????? ????

NOW, if the Gen and VR are grounded,,,,,all is wired correct,,,,, ,,BAT terminal on VR or Cutout Relay is HOT,,,,, ,,Belt is tight,,,,, ,,,Ammeter is good n continuous n works but she wont charge, have you had the batteries tested lately????? Is there electrolyte above all the plates and no cells have a gray or milky appearance????? A bad battery may not accept a charge you know!!!!! !! If the battery checks okay, proceed below to see if its a Gen or VR problem (AFTER you have insured the wiring per the above)


5. a) VOLTAGE REGULATOR SYSTEM: With the tractor running, temporarily ground the Gens Field post to case. If she charges then but NOT otherwise, the VR may be bad, or a wires missing from VR's Field post to the Field terminal on the VR, or the VR isnít well grounded.

b) IF ITíS A CUTOUT RELAY SYSTEM and she charges only if you dead ground the Field but NOT otherwise, its either a bad switch or the switch isnít well grounded or else the wires bad or open from the Gens Field post up to the switch. INSURE THAT GOOD SWITCH GROUND AND WIRING

6. If she still donít charge, leave the Field grounded and jump a wire across from the VR or Cutout Relays BAT terminal over to its GEN terminal (jump by passes the cutout relay) and see if she charges. If then but not otherwise, a VR's cutout relay isnít working correct (maybe points burned/carboned) or a Cutout Relays NOT working or not wired correct.

7. With the 2 steps above, you have basically by passed the VR or Cutout relays functions, so if she still donít charge, you're left with a bad battery or wiring or the Gen itself.

8. MOTOR TEST. You can Motor test the Gen. If its grounded and you remove the belt and apply hot battery voltage direct to its ARM Post and have the Field Post dead grounded to frame, it should motor n run well (Armature n Brushes and Commutator likely okay). Then, if you next remove the Fields ground and it speeds up some, the Fields probably good. If it passes both those tests, it should charge, and if not, it may be a wiring or battery or grounding problem. The hot battery voltage may be taken off the VR's BAT terminal or the starter post or the battery itself for this test.

9. Typical Gen problems may be the brushes are worn down or the hold down spring assemblies are stuck/corroded/dirty and arent pushing the brushes tight down against the commutator. Check those things out. Worse may be bad fields or armature etc. Air and WD 40 etc can clean and free them, the hold downs must be free n snap and hold the brushes DOWN TIGHT and they cant be worn down too low.

SUMMARY: Check the wiring,,,,,the grounds,,,,, insure BAT on VR or Relay is hot,,,,, ,check battery (maybe load tested and Specific Gravity checked),,,,, ,,,good tight belt,,,,, ,insure ammeter is continuous (BOTH sides HOT),,,,, see if battery voltage rises above 12.6 (half that for 6 volt system) and/or light glow brighter,,,,, ,,,do the Field and cutout relay VR by pass checks,,,,, ,,insure the Gens brushes arent worn down and the hold down springs are free n clean and push the brushes down tight,,,,, ,,,,,check the connections,,,,, ,,,try the Gen Motor Test to see if its good.

You may just have a bad battery or bad ground or connection if the Gen and VR or relay are okay. Good Luck n God Bless, let us all know.

John T Nordhoff in Indiana, retired electrical engineer who usually lurks over on the Mother Deere pages instead of over here on the "dark side" lol

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Texas Denny

03-25-2008 13:00:46

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 Re: wd 45 voltage regulator in reply to ohio dairy, 03-25-2008 06:57:22  
Ideal voltage should be between 6.75 volts and 7.2. So, your voltage is fine. If you are using the light switch to control the generator, you need to check this voltage during different conditions. It may be a little lower than that immediately after starting. It may rise slightly when the battery is fully charged requiring a switch change to slow charge. The next issue is will it generate enough current to run the lights. It should work fine during the day.

I have a D-14 on 6 volt. The generator works fine during the day time. When I require lights, it can't keep up with the current draw from the lights. The original plan was three lights of about 5 amps (30 Watts) each. Sometime before I bought it, the original lights were changed to sealed beam lights that take around 10 amps each. They are bright but even two will cause a discharge. I haven't been able to get more than 15 amps out of the original generator. So I either must find a bigger generator or (as I have done) disconnect two of the lights! By the way, the IT manual says it is a 35 amp generator. Interesting!

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paul sebek

03-25-2008 20:12:42

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 Re: wd 45 voltage regulator in reply to Texas Denny, 03-25-2008 13:00:46  
Rip off the lights and replace with original ones that can be found on various sites. Problem fixed.

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ohio dairy

03-25-2008 11:59:55

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 Re: wd 45 voltage regulator in reply to ohio dairy, 03-25-2008 06:57:22  
sounds like the genn is ok. I posted a week or two ago and the real problem is we melted the cut out regulator. it lasted for a few months and before that we used a solid state. which only lasted a few minutes. the light switch works fine high and low charge. gauge is fine to no draw when shut off

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03-25-2008 09:24:53

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 Re: wd 45 voltage regulator in reply to ohio dairy, 03-25-2008 06:57:22  
Well if its a 6 volt system 7 volts isn't all that bad but maybe a tad low. If its keeping the battery charged up I would leave well enough alone

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Peculiar Farmer

03-25-2008 09:09:02

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 Re: wd 45 voltage regulator in reply to ohio dairy, 03-25-2008 06:57:22  
Are you dealing with 6 or 12v? My suggestion would be to go to Page 9 and look under WD45 Generator and check out John T's post, worked for me. That should cover it, if not hail him.

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