# Generator Over-voltage



## liamalxd (Aug 16, 2013)

Hey guys,

I recently bought a cheap 2nd hand chinese branded petrol 4 stroke 2.5KW 6.5HP single phase 240volt generator, it had been in storage years and i've had to completely wash down and clean the carburetor and fuel tanks (had stale fuel inside). 

I have now got the generator up and running and even fixed other problems that were wrong with it (such as engine grounding etc).

The last problem I'm faced with is electrical/engine related.

When the generator has the air choke open past a certain point the engine speeds up and the generator kicks out 300+ volts from the 240V socket, obviously heating and lighting don't mind this but i'd never attach anything electronic to it.

Is this an engine fault or a wiring fault?

The alternator has L1,L2,R1 and R2 for high voltage outputs, each of which are producting 180Volts when the engine runs away with the choke open.

If i i limit the air intake choke to just slightly over complete closure the engine runs smoothly and produces 240-250v which is about close enough.

I'm just wondering if this is its normal function or there is a serious problem?

Thanks.


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## KRE (Nov 29, 2011)

Most likely your generator is a volts/hertz curve unit. Ie with a increase in speed above the target set point, your voltage will clime. 3780rpm should be max no load speed, for a 5% droop governor and a two pole unit.

Hope this helps,
Kenneth


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## FISH (Aug 15, 2013)

You need to determine if it is a problem with your carb/throttle, or with the gov.
mechanism. The throttle shaft could just be stuck open, so grab it and try to rotate it, it may just be gummed up.


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## liamalxd (Aug 16, 2013)

The gov seems fine, re-adjusts when i move it.

Could a lack of fuel be causing this? for example when i turn the choke down and put less air in it cuts out?

(i suspect the fuel tank valve may be gummed up)

or is it a case of just adjusting the choke to let in the correct amount of air every time?


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## liamalxd (Aug 16, 2013)

Think i've gotten to the bottom of it from research, think i need to alter the gov screws on the carb ... slow down the engine so it kicks out the correct voltage...


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## liamalxd (Aug 16, 2013)

For anyone else experiencing this problem, the cause is the generator governor.

You need to re-adjust it using the tension screw on the governor, and that will slow down the speed of the engine;
Use a multi-meter to tune the engine to the correct voltage you need (e.g 220v)

Thanks guys.


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