‘88 520H blowing 30A fuse randomly

[lynnmor 7,307]

23 minutes ago, Evguy said:

The regulator needs about 5 volts on b to even work. 
I read something on my 314 to not run without a battery or damage to electrical system could result, not sure what they are referring to 

There is a warning decal on many Wheel Horse tractors about running without a battery.

[Jeff-C175 7,202]

I'd really like to reverse engineer one of those potted regulators.

 

It's very possible that the regulator will not function properly without the battery as a 'load'.

 

The voltage could go too high, ruin coils, blow light bulbs, and even the regulator itself could theoretically be damaged.

 

 

[953 nut 55,290]

9 hours ago, Snoopy11 said:

 

That is really the basis of my question... what is the voltage range at regulator output terminal? What should we be looking for?

What we all call a voltage regulator is in reality a rectifier, it converts alternating current into pulsating direct current. The AC from your stator is variable with engine RPMs and the DC reading will be directly proportional to the AC voltage.

There are two diodes in the rectifier, one will pass the positive pulse of the AC and the other will convert the negative pulse into positive pulsation giving you pulsating DC. These pulsations occur so rapidly that they are undetectable without the use of an oscilloscope. The DC voltage will be an average of the highest and lowest points of the pulsations. Since the stator produces about 36 volts AC and more than half is lost in the process of rectification you can expect to see no more than 15 no-load volts reading on the DC output.

 

https://en.wikipedia.org/wiki/Rectifier

[squonk 41,145]

Those plastic fuses will normally melt due to prolonged heat before blowing. We experimented with those fuses back in my Napa days. One of the guys direct shorted across a battery with a pair of pliers. fuse held and the pliers burned up! 

 

I've had several Horses where the fuse holder was bad, the fuse plastic melted and the fuse kept working.

 

While it's certainly possible for a bad fuse holder to be causing the fuse failure, I would download a manual and find out what's on that circuit. More than likely a wire is chafed somewhere and while the tractor runs the vibration makes it hit a body panel and shorts it out.

[gwest_ca-(File Mod) 11,046]

Download this file for individual circuits

 

[dr363305 50]

13 minutes ago, gwest_ca said:

Download this file for individual circuits

 

Already have it. The circuit where the 30amp fuse is clearly identified is the tachometer circuit. I need to go look again, but I would expect this fuse to be called out on the charging circuit.

[lynnmor 7,307]

1 hour ago, 953 nut said:

What we all call a voltage regulator is in reality a rectifier, it converts alternating current into pulsating direct current. The AC from your stator is variable with engine RPMs and the DC reading will be directly proportional to the AC voltage.

There are two diodes in the rectifier, one will pass the positive pulse of the AC and the other will convert the negative pulse into positive pulsation giving you pulsating DC. These pulsations occur so rapidly that they are undetectable without the use of an oscilloscope. The DC voltage will be an average of the highest and lowest points of the pulsations. Since the stator produces about 36 volts AC and more than half is lost in the process of rectification you can expect to see no more than 15 no-load volts reading on the DC output.

 

https://en.wikipedia.org/wiki/Rectifier

I think you will find that the regulator rectifier actually regulates the voltage and is not just a simple bridge rectifier.  Until someone does an autopsy on a failed one we don't know for sure.  You might find that the excess current is shunted to ground to maintain the proper voltage.

[squonk 41,145]

1 hour ago, dr363305 said:

Already have it. The circuit where the 30amp fuse is clearly identified is the tachometer circuit. I need to go look again, but I would expect this fuse to be called out on the charging circuit.

That 30 A fuse goes thru connector pin # 9 and to a 20A fuse to the tach. If there was an issue with say the tach side of the circuit the 20a fuse would blow before the 30A fuse. I think you issue is with the regulator and or wiring on that side of pin 9

[dr363305 50]

13 minutes ago, squonk said:

That 30 A fuse goes thru connector pin # 9 and to a 20A fuse to the tach. If there was an issue with say the tach side of the circuit the 20a fuse would blow before the 30A fuse. I think you issue is with the regulator and or wiring on that side of pin 9

I agree with this statement. The 20A fuse has remained intact and without fail. I need to get to rewiring the engine side harness. I am not a fan of the harness being ran in heat resistant material and laying on the engine. 
 

I have yet to pull back that heat resistant sheathing and discover what wonderful surprises lie within lol.

Edited October 24, 2022 by dr363305
Cant english

[Handy Don 12,233]

3 hours ago, 953 nut said:

more than half is lost in the process of rectification

The regulator is more than a pair of diodes, of course. Its circuitry also compares the "charging" voltage to the "battery" voltage and prevents "over voltage" to the battery (this effort soaks up some current which becomes heat--that's where part of the "half lost" is going and is why the VR needs those cooling fins).

Edited October 24, 2022 by Handy Don

[Jeff-C175 7,202]

4 hours ago, 953 nut said:

reality a rectifier

 

As others have pointed out, it's more than that.

 

I believe it's BOTH a Voltage AND a Current regulator.

 

Most stators put out a lot more voltage than just the 14 or so volts.

 

The 'regulator' setpoints should limit the charge current and the maximum voltage.

 

If anyone has a 'dead' regulator they don't want, I'd be happy to try and 'un-pot' it and reverse engineer it if possible.  I don't know that the potting epoxy can be removed without destroying the electronics inside, but I'd be willing to give it a try.  

 

 

[Snoopy11 5,714]

16 minutes ago, Jeff-C175 said:

 

As others have pointed out, it's more than that.

 

I believe it's BOTH a Voltage AND a Current regulator.

 

Most stators put out a lot more voltage than just the 14 or so volts.

 

The 'regulator' setpoints should limit the charge current and the maximum voltage.

 

If anyone has a 'dead' regulator they don't want, I'd be happy to try and 'un-pot' it and reverse engineer it if possible.  I don't know that the potting epoxy can be removed without destroying the electronics inside, but I'd be willing to give it a try.  

 

 

What is interesting... I think... is that there doesn't seem to be 1 certain agreement on the operation of regulators. Everyone seems to have a different perception of them.

 

All I know is that when I built my Techy engine... I made a video (that got deleted to save storage space on the forum)... and it showed the voltage output of my engine at 14.6 volts regulator output terminal with no battery connected. The way I feel about regulators, if it would have put out more voltage than that (say... 15+ volts), I would have sent the regulator back to IST... as I do not feel that it would be working properly if it allowed that much voltage to go to the battery.

 

I might test the regulator on my other engines to see what they put out to see if there are any differences between machines.

 

Don

Edited October 24, 2022 by Snoopy11

[Jeff-C175 7,202]

1 minute ago, Snoopy11 said:

agreement on the operation of regulators

 

Not everyone understands electronics, perhaps that is why?

 

Ideal charging conditions for a lead acid are a "Constant Current then Constant Voltage" charge.

 

I use 14.5 V as the "Constant Voltage" part.  I limit the charge current to 10 % of the Amp Hour rate of the battery.

My 'charger' is actually a DC power supply that can do both CC and CV.  It automatically switches to CV once the battery is charged.

 

The 'regulator' is not as precise as this though... probably quite simple in fact, but it should limit both current and voltage to prevent over charging the battery and 'cooking' it.

 

 

[Snoopy11 5,714]

1 minute ago, Jeff-C175 said:

over charging the battery and 'cooking' it.

Exactly what would be my concern.

 

Probably a primitive thought... but the chargers that I have in my possession (trickle style chargers, and full blown car battery chargers) do not exceed 15 volts output while charging... so why should the regulators on my machines?

 

Don

[Evguy 556]

1 hour ago, Jeff-C175 said:

 

As others have pointed out, it's more than that.

 

I believe it's BOTH a Voltage AND a Current regulator.

 

Most stators put out a lot more voltage than just the 14 or so volts.

 

The 'regulator' setpoints should limit the charge current and the maximum voltage.

 

If anyone has a 'dead' regulator they don't want, I'd be happy to try and 'un-pot' it and reverse engineer it if possible.  I don't know that the potting epoxy can be removed without destroying the electronics inside, but I'd be willing to give it a try.  

 

 

I have a few bad ones, not sure if I didn’t pitch them, I would donate for examination.

 I’m fighting charging system on my 314, I was going to build a regulator for it since they keep failing.

[Handy Don 12,233]

6 hours ago, Jeff-C175 said:

The 'regulator' is not as precise as this though... probably quite simple in fact, but it should limit both current and voltage to prevent over charging the battery and 'cooking' it.

The regulators on S/G systems do regulate both voltage and current and are even more interesting. They use mechanical relays with adjustable springs that rapidly interrupt the flow of current to the battery based on both voltage and current. Similar regulators on older outdoor equipment frequently added a third relay to provide temperature compensation (cold batteries need more current to charge than hot batteries).

This was because generators provide DC current where voltage depends on speed and the regulator couldn't rely on detecting AC current pulses whereas stators supply AC and the reversing polarity can be harnessed to control the regulator.

I've read of people that have created a solid state replacement for an S/G regulator and it is no mean feat. ISaveTractors wanted to commission production of such a regulator but it became quickly apparent that the sales volume would not justify getting them into production at an attractive price. Instead, they continue to sell a high quality mechanical regulator.

Edited October 24, 2022 by Handy Don

[Jeff-C175 7,202]

5 hours ago, Evguy said:

I have a few bad ones, not sure if I didn’t pitch them, I would donate for examination.

 I’m fighting charging system on my 314, I was going to build a regulator for it since they keep failing.

 

PM me (or email) if you find them.

 

 

Edited October 24, 2022 by Jeff-C175

[Jeff-C175 7,202]

3 hours ago, Handy Don said:

mechanical regulator.

 

I'm familiar with those, my first half dozen cars used them.  In fact, in a box from my FIL's service station there are a number of them, some NOS.  Late 30s, early 40s vintage.