# LOW Voltage on Olympian generator, troubleshooting help needed



## RBE (Aug 6, 2018)

Hi there, 

I'm in need of some troubleshooting help for an elderly gentleman in town. My background is industrial electrical, working on Nuclear sites, assembly lines and automation but my generator knowledge is limited to say the least.

The unit is an Olympian 15kw Generator *model G15U1S* with an ATS. The Generator is physically large for a 15KW for todays standards but its coolant cooled and used to work great. Unit was switched to manual mode instead of automatic mode and taken off automatic weekly testing a few years back due to complaints. 

I was called because on a recent power outage, the owner went to turn it on. The generator started but the automatic transfer switch didn't kick in. 

I went to have a look, did a few simulations and tests and this is what I noticed:

ATS doesn't indicate (led on front of panel) the generator is running when it's running.

ATS does not switch over to generator when mains/utility power is lost.

Generator starter motor tries to engage a couple of times after the generator is running. 2 or 3 times every 5 seconds then it stops trying. Sounds similar to when someones tries to start an already running car. I'm assuming the ATS is telling it to start due to it not seeing it running. 

Tested voltage coming out of generator at generator. Voltage was down...... L1-N = 80v L2-N =80v L1-L2 =160v

I did not test HZ (my mistake), but that should not affect the voltage value if i remember correctly.

All i can think from my limited knowledge on generator is that either:

1) the AVR is not working properly. Anyone know how to test this specifically, maybe down to certain components?
2) low engine RPM's may be down which equal low HZ but should not affect voltage value.
3) problem with alternator. Anyone know how to test also on this model. The thing is a little difficult to access and see where you would be putting your probes. 

I believe if i can get the generator to produce correct voltage, the ATS will see it and operate correctly. I'm working on the assumption right now that the ATS isn't seeing the generator due to the voltage input values not meeting spec, to operate correctly. 

Any help on how to go forward, testing the AVR or/and alternator would be greatly appreciate!
If i'm on the wrong track, please let me know.
Picture below is one I pulled from the internet but looks the same at a glance.
I'll wait back for any response. Thanks. 

Kind Regards
Johnny


----------



## RBE (Aug 6, 2018)

I've gone through the technical operation manual and maintenance manual pretty closely for this unit. It talks about how to test the alternator and AVR in the Alternator manual which i do NOT have. Really struggling to find any information on this or that manual. 

Does anyone have any on the job experience on these units and can point me in the right direction????? I'm going to head over there again this week sometime and have another look inside the alternator. 

regards
Johnny


----------

