# Voltage Drop under load



## gunshin (Dec 16, 2014)

Hey guys, 
Need some assistance here. 
working on a Kohler 100REOZJB 100KW 3 ph 208 60hz unit with John Deere 6068TF250 engine. No electrical governor. it's a Stanadyne DB4 pump. 

runs fine at idle, 120/208 60hz
put on load bank (resistive) and the voltage drops, the more load I add, the more it drops. So far I've rebuilt/replaced injection pump, injectors, LED board, Speed Sensor, Megged windings, tested transistor board and motherboard. Flashlight test passed as well. Connect it to load bank and under 20KW It goes from 208 to 200, 40KW it goes down to 190vac etc. Speed drops a small bit from 60hz to 59. Ohmed out all cables, wires, connections etc for short and nothing found. IR LED in rotating SCR has been verified to be working. SCR taken off and tested, tested good. 
Motherboard has been looked at and all the components checked out, VR was also replaced. I'm stumped.


----------



## aandpdan (Oct 8, 2012)

Not familiar with the generator Gunshin. It does sound like a VR problem however. If the engine is holding RPM's - a slight drop is normal - then the field current isn't high enough to maintain voltage.


----------



## Dqalex (Nov 25, 2012)

gunshin said:


> Hey guys,
> Need some assistance here.
> working on a Kohler 100REOZJB 100KW 3 ph 208 60hz unit with John Deere 6068TF250 engine. No electrical governor. it's a Stanadyne DB4 pump.
> 
> ...


Try this Kohler forum. I sure they can help. Kohler Generators - SmokStak


----------

