voltage regulator

Bill8200

New member

Equipment
B8200
Oct 12, 2020
29
1
3
PA
just put a new voltage regulator in and was wondering what kind of voltage readings you guys get. i think the old one was causing my battery to leak out from over charging. right now, i'm getting about 12 at idle and up to 14 when i rev the engine up.
 

85Hokie

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BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
Jul 13, 2013
10,752
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Bedford - VA
In your other post you asked why a dynamo was used - pure simplicity. I coil of wire is spun around a magnet or a magnet is spun around a coil of wire. Two lead come out with AC voltage.

The voltage from that is converted to DC via the diodes in a the voltage regulator.

You output is spot on - about 12 volts (maybe 12.4) at idle and 14 ish at WOT.
 
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Bill8200

New member

Equipment
B8200
Oct 12, 2020
29
1
3
PA
In your other post you asked why a dynamo was used - pure simplicity. I coil of wire is spun around a magnet or a magnet is spun around a coil of wire. Two lead come out with AC voltage.

The voltage from that is converted to DC via the diodes in a the voltage regulator.

You output is spot on - about 12 volts (maybe 12.4) at idle and 14 ish at WOT.
Sounds good; thanks!!
 

F.W.T.

New member

Equipment
Kubota B 7200
Nov 15, 2020
3
0
1
ohio
I'm looking on line for a B 7200 voltage regulator. Prices vary wildly from about $35.00 with free shipping to $102.00 plus $12.00 shipping. I'm looking for advise from people who have purchased a VR from both ends of the price spectrum and your experience including shipping, quality, and longevity of use. Thanks
 

85Hokie

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Staff member
Lifetime Member

Equipment
BX-25D ,PTB. Under Armor, '90&'92-B7100HST's, '06 BX1850 FEL
Jul 13, 2013
10,752
2,559
113
Bedford - VA
I'm looking on line for a B 7200 voltage regulator. Prices vary wildly from about $35.00 with free shipping to $102.00 plus $12.00 shipping. I'm looking for advise from people who have purchased a VR from both ends of the price spectrum and your experience including shipping, quality, and longevity of use. Thanks

shoot .... here is one AT WALMART (online)if you can imagine that !

It might be worth it - you MIGHT want to go ahead in THIS particular case and get the 3 year warranty too - normally I would say not, but in this case, it might be a good thing.

IF THIS does not work - simply return to your local walmart and get money back - that is one good thing
about wallyworld, most have one near by and if you need to send something back, you can drop it off and they will give you your money back.

What is your machine not doing? Have you checked the AC voltage from dyno?
 

GeoHorn

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M4700DT, LA1002FEL, Ferguson5-8B Compactor-Roller, 10KDumpTrailer, RTV-X900
May 18, 2018
6,040
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113
Texas
shoot .... here is one AT WALMART (online)if you can imagine that !

It might be worth it - you MIGHT want to go ahead in THIS particular case and get the 3 year warranty too - normally I would say not, but in this case, it might be a good thing.

IF THIS does not work - simply return to your local walmart and get money back - that is one good thing
about wallyworld, most have one near by and if you need to send something back, you can drop it off and they will give you your money back.

What is your machine not doing? Have you checked the AC voltage from dyno?
Hokie, ... is that true? I mean, have you actually done that?.. bought from WalMart online and returned at a local store?
 

DrankTheOrangeKoolaid

Member

Equipment
M6800/M920, Case 780B
Sep 24, 2019
99
34
18
Alberta
Hokie, ... is that true? I mean, have you actually done that?.. bought from WalMart online and returned at a local store?
This is walmart's equivalent of the amazon marketplace. This item isn't sold by walmart, but by a seller going by the name Rareelectrical. According to walmart "Walmart requires sellers to use minimum standards for item returns, but each seller has their own policy." In this case, the item can be returned to a store. As with most things, caveat emptor.
 

F.W.T.

New member

Equipment
Kubota B 7200
Nov 15, 2020
3
0
1
ohio
shoot .... here is one AT WALMART (online)if you can imagine that !

It might be worth it - you MIGHT want to go ahead in THIS particular case and get the 3 year warranty too - normally I would say not, but in this case, it might be a good thing.

IF THIS does not work - simply return to your local walmart and get money back - that is one good thing
about wallyworld, most have one near by and if you need to send something back, you can drop it off and they will give you your money back.

What is your machine not doing? Have you checked the AC voltage from dyno?
I have to admit I did not think of Walmart! Throughout the summer I had to use my jump pack to get it started. I did check the Dyno, about 15 VAC in idle and About 30 VAC full throttle. With the tractor running I disconnected the positive lead to the battery and measured 0 VDC. To the best of knowledge wiring and VR are the only components between the two. A quick inspection of the wiring did not indicate and rodents snacking or cracked insulation. I don't have a schematic with the wiring color code to check input and output so my guess is the VR is bad. Any assistance with wiring into and out of the VR is appreciated. Am I missing anything? Thanks Guys
 

Bill8200

New member

Equipment
B8200
Oct 12, 2020
29
1
3
PA
I'm looking on line for a B 7200 voltage regulator. Prices vary wildly from about $35.00 with free shipping to $102.00 plus $12.00 shipping. I'm looking for advise from people who have purchased a VR from both ends of the price spectrum and your experience including shipping, quality, and longevity of use. Thanks
my search was the same for b8200: $30-$100. i ended up getting the cheapest one i could find here https://www.amazon.com/gp/product/B06XX7TML1/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
so far, so good. i have no idea if one that costs 3x's that is worth the money, but so far i'm satisfied.
 

Bill8200

New member

Equipment
B8200
Oct 12, 2020
29
1
3
PA
I'm looking on line for a B 7200 voltage regulator. Prices vary wildly from about $35.00 with free shipping to $102.00 plus $12.00 shipping. I'm looking for advise from people who have purchased a VR from both ends of the price spectrum and your experience including shipping, quality, and longevity of use. Thanks
also, learn how to remove a steering wheel. i have never done it before and had quite a time with it. ultimately what worked was two guys pulling up hard on the wheel and one of them beating on the spline with a 3 lb drill hammer on a piece of bar stock.
 

whitetiger

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Equipment
Kubota tech..BX2370, RCK60, B7100HST, RTV900 w plow, Ford 1100 FWA
Nov 20, 2011
2,925
1,386
113
Kansas City, KS
I don't have a schematic with the wiring color code to check input and output so my guess is the VR is bad. Any assistance with wiring into and out of the VR is appreciated. Am I missing anything? Thanks Guys
Here are the Charge schematic and Complete wire schematic with colors.
 

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Dave_eng

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Lifetime Member

Equipment
M7040, Nuffield 465
Oct 6, 2012
5,236
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Williamstown Ontario Canada
Lugbolt, a knowledgeable forum member, previously posted this charging system diagnostic procedure:

Dave


the books are jinglish, and IMO hard to follow.

thus I have my own tests

the regulator/rectifier has 6 wires. 2 are the same color, they end up at the dynamo. AC. One is a black ground wire. You will also have a +12v from the slow-blow fuse, and a +12v ignition (key on) and then a wire that runs to a charge lamp (if applicable, but it'll still have that wire).

Typically loss of charging performance is fairly easy to diagnose if you have the know-how, and a digital volt-ohm meter that has any quality whatsoever. A $10 one isn't that, just something else to throw into file 13 when it reads wrong.

The two dynamo wires (usually sky blue) are AC voltage, as said. Start engine, disconnect regulator and test ac output at the regulator connector, between the two dynamo wires. Should be 24V+ and I like to see more than 45 or so at full throttle. If it charges anything it's probably ok, they are a foolproof and extremely simple design that rarely fails outside of seized bearings. OK? Move on. Check your ground at the reg connector. One probe of the DVOM (set to ohms) on the ground pin in the connector and the other pin on a good ground, frame, transmission, etc. Must be clean. If you have more than a few ohms of resistance, your ground or harness is suspect

onward. Find your wire that comes from the battery. Backprobe the regulator connector. Now put your DVOM on DC volts. One probe goes to your connector, the other goes to the battery +. Should be under 500mv, or 0.500v. Ok? Move on. More than 0.5v? You have either a harness problem or a bad connection at the fuse, or whatever.

Last wire that will affect charging is what I call the "trigger" wire...it turns the reguator "on" so to speak, via the key switch. That one gets 12v when the key is on. Same as the last test, backprobe the connector with the key on. One probe of the DVOM in the connector and the other to the + battery terminal (use the post not the cable). You want to see less than 0.5v on the meter. If you see more than that, harness, fuse block, keyswitch, etc. Follow your wiring diagram. If you do see less than 0.5v, that circuit is not suspect, and there's a possibity you have a bad regulator.

Ideally you want to test everything AROUND the regulator because testing the reg itself isn't always conclusive. Thus, once you know you have AC voltage from the dynamo, you have good ground, you have +12v from the batt and ignition switch, the only component left is the reg. Process of elimination.

Electrical diag is not all that hard or it can be. It's all what you make of it. Don't put too much thought into it because it'll bite you. It's simple for the most part

speaking of being bit, be careful around the dynamo wires when testing. There's a little bit of voltage there and it's ac voltage, so it can bite you.
 

F.W.T.

New member

Equipment
Kubota B 7200
Nov 15, 2020
3
0
1
ohio
Lugbolt, a knowledgeable forum member, previously posted this charging system diagnostic procedure:

Dave


the books are jinglish, and IMO hard to follow.

thus I have my own tests

the regulator/rectifier has 6 wires. 2 are the same color, they end up at the dynamo. AC. One is a black ground wire. You will also have a +12v from the slow-blow fuse, and a +12v ignition (key on) and then a wire that runs to a charge lamp (if applicable, but it'll still have that wire).

Typically loss of charging performance is fairly easy to diagnose if you have the know-how, and a digital volt-ohm meter that has any quality whatsoever. A $10 one isn't that, just something else to throw into file 13 when it reads wrong.

The two dynamo wires (usually sky blue) are AC voltage, as said. Start engine, disconnect regulator and test ac output at the regulator connector, between the two dynamo wires. Should be 24V+ and I like to see more than 45 or so at full throttle. If it charges anything it's probably ok, they are a foolproof and extremely simple design that rarely fails outside of seized bearings. OK? Move on. Check your ground at the reg connector. One probe of the DVOM (set to ohms) on the ground pin in the connector and the other pin on a good ground, frame, transmission, etc. Must be clean. If you have more than a few ohms of resistance, your ground or harness is suspect

onward. Find your wire that comes from the battery. Backprobe the regulator connector. Now put your DVOM on DC volts. One probe goes to your connector, the other goes to the battery +. Should be under 500mv, or 0.500v. Ok? Move on. More than 0.5v? You have either a harness problem or a bad connection at the fuse, or whatever.

Last wire that will affect charging is what I call the "trigger" wire...it turns the reguator "on" so to speak, via the key switch. That one gets 12v when the key is on. Same as the last test, backprobe the connector with the key on. One probe of the DVOM in the connector and the other to the + battery terminal (use the post not the cable). You want to see less than 0.5v on the meter. If you see more than that, harness, fuse block, keyswitch, etc. Follow your wiring diagram. If you do see less than 0.5v, that circuit is not suspect, and there's a possibity you have a bad regulator.

Ideally you want to test everything AROUND the regulator because testing the reg itself isn't always conclusive. Thus, once you know you have AC voltage from the dynamo, you have good ground, you have +12v from the batt and ignition switch, the only component left is the reg. Process of elimination.

Electrical diag is not all that hard or it can be. It's all what you make of it. Don't put too much thought into it because it'll bite you. It's simple for the most part

speaking of being bit, be careful around the dynamo wires when testing. There's a little bit of voltage there and it's ac voltage, so it can bite you.
I want to thank everyone for the help. I will check the wiring and locate the fuse shown on the schematic and check for continuity. I will report back with my findings and any components that I replace. If testing points to the VR I will most likely order one on line, please stand by.