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Why does my generator voltage rise with increasing load?

Dear All, I am trying to power up a micro-grid providing power to over 50 households and businesses on a remote island ...
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I posted an answer on this last night and then woke up thinking "Oh no! That doesn't make sense!" so here goes again in the spirit of trying to help. . Is the AVR a separate box - one of the clickety-click types on the market there or is it more sophisticated? . How does the generator behave when loaded by a more straightforward resistive kind of load like a heating element when the AVR (if a separate item) is not in the loop? Put a couple of different resistive loads on it and check the voltage and frequency. Why do you need an AVR if using a small generator or do you sometimes have mains power that is unreliable? . Have you checked the voltage and frequency coming from the generator? (I was under what may be a false belief that these small portable generators used speed regulation to maintain voltage so if you see a frequency rise on increasing load I would suspect the generator speed regulation to be at fault.)

The chaps on this forum may be able to help:

Don't forget to let us know how you get on! Tricky one this!

All the best //Steve

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Thanks Steve. The AVR is built into the generator and when you turn the little potentiometer down the idling voltage of the generator goes down and vice versa. It makes little difference when the generator is attached to the inverter/charger however, the same increasing voltage is observed. The voltage coming from the generator is what I have been measuring, but I have not been able to measure the frequency. There does not seem to be a corresponding increase in engine rpm with the increasing voltage. It is a good idea to try a different restive load. I will do so. Thanks for the link and thanks so much for your kind advice too. We'll get to the bottom of this somehow!

Odhiambo gravatar imageOdhiambo ( 2014-03-19 10:03:33 -0500 )edit

some AVR has current compensation . positive or negative. may be you have positive . these means that when load increase you increase voltage setting to compensate for the drop. if so reduce this setting or put it to negative.


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2014-03-18 07:37:28 -0500
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Mar 18 '14