Drash Isuzu voltage regulator

[Joe Bertram]

Does anyone know the ins and outs of these units? Recently acquired one from GP and had it shipped. Got it running great with batteries and a fuel filter. But the generator only makes 88 volts to ground on each leg. Found that if I put tension on the potentiometer by pushing it up or down on the voltage regulator it would go to 125 and even adjust some till I let go of it and right back to 88 volts. Found voltage regulator on eBay tried it tonight seems to just jump back and forth now between around 90-150 volts per leg and never stays constant. Where do I go from here. Drash generator including the EUC that appears to be in working order

 

[Scoobyshep]

Does anyone know the ins and outs of these units? Recently acquired one from GP and had it shipped. Got it running great with batteries and a fuel filter. But the generator only makes 88 volts to ground on each leg. Found that if I put tension on the potentiometer by pushing it up or down on the voltage regulator it would go to 125 and even adjust some till I let go of it and right back to 88 volts. Found voltage regulator on eBay tried it tonight seems to just jump back and forth now between around 90-150 volts per leg and never stays constant. Where do I go from here. Drash generator including the EUC that appears to be in working order

Never played with one but it almost sounds like the pot is dirty (wiper is making poor contact) . If it were me I would look at cleaning the coil to wiper contact surface (if its an open pot) or an old trick is to rapidly and repeatedly twist the knob back and fourth (the wiper can decrapify the contact point)

 

[Coug]

To go along with the above, if it isn't a sealed pot then using a product like this one can help with cleaning and deoxidizing the contacts if that is the issue

Amazon.com

 

[Scoobyshep]

To go along with the above, if it isn't a sealed pot then using a product like this one can help with cleaning and deoxidizing the contacts if that is the issue

View attachment 819659

Amazon.com

DeoxIT Magic in a can

 

[Poccur]

Never played with one but it almost sounds like the pot is dirty (wiper is making poor contact) . If it were me I would look at cleaning the coil to wiper contact surface (if its an open pot) or an old trick is to rapidly and repeatedly twist the knob back and fourth (the wiper can decrapify the contact point)

Never played with one but it almost sounds like the pot is dirty (wiper is making poor contact) . If it were me I would look at cleaning the coil to wiper contact surface (if its an open pot) or an old trick is to rapidly and repeatedly twist the knob back and fourth (the wiper can decrapify the contact point)

Is it a Marathon SE350 for the voltage reg?

 

[Joe Bertram]

Is it a Marathon SE350 for the voltage reg?

Yes it's a se350 marathon regulator

 

[Poccur]

Yes it's a se350 marathon regulator

So assuming you have the new regulator on..and unit is turned off..

There is a test you can do which will prove to you that the generator is capable of making voltage and being stable. That will put your mind at rest that the issue is the regulator.

If you unhook F+ and F- from the regulator then carefully attach the wires you pull off to a 12 volt battery. F+ to positive, F- to negative...That removes the regulator from the circuit and pushes 12vdc down into the generator. Leave wires connected and restart engine...voltage should shoot up to around 220 VDC and be stable...Basically the battery is taking the place of the regulator and exciting the field in the generator to make voltage.
When I do this test I use wires with an inline fuse as the car battery I have for the 12volts has way too many amps for safety if the wires ground out by accident....really recommend you use fuse or circuit breaker on battery wires.

Reconnect F+ and F-...
Fire up the system and focus on the dials on the top of the regulator..
The regulator has three adjustable settings:

1.Volts
2.Stability
3.U/F

•The ‘volts’ is the main voltage adjustment point for the system, you dial it till you get the voltage you want...

•Stability controls the ability of the voltage regulator to respond to load changes
•To set the stability, run the engine with no loads on it
•Dial the stability counter clockwise until the voltage becomes unstable
•Now dial to clockwise until the voltage becomes stable
•Shut down and restart the system
•Voltage should be stable
•If the voltage becomes unstable again, dial the stability setting a small amount further clockwise
•Repeat shutdown and test until success

•U/F is the voltage roll off
•This is the point where the regulator will reduce the voltage to allow the engine to recover in an overload condition
•To set U/F:
•Set engine speed to desired roll off point (58Hz)
•Dial U/F counter clockwise until voltage begins to drop
•Dial U/F clockwise until voltage just recovers
•Set engine speed back to 60Hz

Done, should be set now...

Any problems, PM me ..

Poccur

 

[Joe Bertram]

View attachment 824508
So assuming you have the new regulator on..and unit is turned off..

There is a test you can do which will prove to you that the generator is capable of making voltage and being stable. That will put your mind at rest that the issue is the regulator.

If you unhook F+ and F- from the regulator then carefully attach the wires you pull off to a 12 volt battery. F+ to positive, F- to negative...That removes the regulator from the circuit and pushes 12vdc down into the generator. Leave wires connected and restart engine...voltage should shoot up to around 220 VDC and be stable...Basically the battery is taking the place of the regulator and exciting the field in the generator to make voltage.
When I do this test I use wires with an inline fuse as the car battery I have for the 12volts has way too many amps for safety if the wires ground out by accident....really recommend you use fuse or circuit breaker on battery wires.

Reconnect F+ and F-...
Fire up the system and focus on the dials on the top of the regulator..
The regulator has three adjustable settings:

1.Volts
2.Stability
3.U/F

•The ‘volts’ is the main voltage adjustment point for the system, you dial it till you get the voltage you want...

•Stability controls the ability of the voltage regulator to respond to load changes
•To set the stability, run the engine with no loads on it
•Dial the stability counter clockwise until the voltage becomes unstable
•Now dial to clockwise until the voltage becomes stable
•Shut down and restart the system
•Voltage should be stable
•If the voltage becomes unstable again, dial the stability setting a small amount further clockwise
•Repeat shutdown and test until success

•U/F is the voltage roll off
•This is the point where the regulator will reduce the voltage to allow the engine to recover in an overload condition
•To set U/F:
•Set engine speed to desired roll off point (58Hz)
•Dial U/F counter clockwise until voltage begins to drop
•Dial U/F clockwise until voltage just recovers
•Set engine speed back to 60Hz

Done, should be set now...

Any problems, PM me ..

Poccur