GENERTAOR LOAD QUERY

[Anonymous user]

Can anyone help with this query...We have a 120kVA generator supplying a 80kVA UPS plus some other services. With total load at only around 60A per phase the generator will not pick up the load. It starts to pick up the load, but as it ramps up towards 60A per phase, it shuts down. The generator is capable of supplying around 140A per phase, and we have proved it can supply more than this into a (resistive) load bank and it can even do this as a 'snatch' load.

It would seem the difference between load bank and real load is making a considerable difference.

Any thoughts appreciated - thanks

[BillP]

You could have any number of problems with that symptom. Is it an APC Smartgen stand-by power generation system? Is it natural gas? What kind of motor load do you have? (Air conditioners, circulation pumps,elevator motors, compressors) and how balanced is the load?
If you are convinced it's load side and not engine, verify the performance curve to the load curve. Something is knocking it out of whack that you can't tell with just amp meters. It's time to do more math and research into the particulars of your installation. Would a service to perform that verification help you?

[Anonymous user · Accepted solution]

I would have to agree with Tech Tuff, it can be many different things. We have recently replaced the governor on our generator (Engine control module) and the load test gave us 90-95% load for 2 hours. However, the real world proved different, when the generator shut down while the building was on emergency source. What we found out was the combination of one of the employees using the elevator and the HVAC compressor motors starting up (5 minute delay after power loss) exceeded the rated load of the generator. So I would pick up some clamp-on Amp meters and do some testing after business hours.