Generator Frequency Drops, Speed Remains Constant

[merryengineer]

Hi,

I have a strange problem. I have a generators and it runs fine spot on at 1500RPM. Its a electronically managed TAD941GE.

When load is applied, sometimes it runs no problem and othertimes the frequency drops sharply causing the unit to shut down on under frequency.

The Engine speed however does not change much, it moves only 2-3 RPM as the load goes on. The full load rating is 260kW, we only have about half that on it.

I have checked the frequency with a multimeter and the same happens, its gives me 50Hz but then shoots all over the place sometimes. Its very strange.

We have changed the AVR and the control module (Deep Sea 7310) but it has not helped to fix the problem.

[wellandpower]

You have a problem with your load.

We had a similar experience, its very tricky to find out.

The problem with the load is destorting the waveform and causing the frequency to change.
If it was a genuine frequency change then the engine speed would also need to change.

It is probably only one item of equipment that has the fault. You could try turning everything off and starting things one by one until you find the fault.

[merryengineer]

Hi thank you.

Yes we have had a fault with a heater in the building. If we don't start that, then there is no problem.