generator over voltage

[Justme]

Currently struggling through a head fog of illness with a 11kw genny that is giving me an over voltage of 333v ac.
Its a single phase unit.
Tried new AVR's all still give same voltage.
Removing avr & output drops to 30v ac.
Tested all joints & windings for shorts & cant find any but dont have a megga to do a high voltage leak test.
My super cheap scope goes crazy & I cant get any sensible readings, but it does read from the inverter fine.

All googling points to over rpm (its not) faulty avr (unlikely 3 are faulty) or loose connections or high resistance which I cant find any.

I just cant find whats up with it.

[Westie]

Currently struggling through a head fog of illness with a 11kw genny that is giving me an over voltage of 333v ac.
Its a single phase unit.
Tried new AVR's all still give same voltage.
Removing avr & output drops to 30v ac.
Tested all joints & windings for shorts & cant find any but dont have a megga to do a high voltage leak test.
My super cheap scope goes crazy & I cant get any sensible readings, but it does read from the inverter fine.

All googling points to over rpm (its not) faulty avr (unlikely 3 are faulty) or loose connections or high resistance which I cant find any.

I just cant find whats up with it.

Need a bit more info mate, is it brushed or brushless, if brushed how many sliprings 2 or 3?

[Tinbum]

All googling points to over rpm

That would just effect frequency.

[rogeriko]

Put a load on it, like an electric heater 2-3kw and then measure it.

[newtoallthis]

I am a mere Mechanical Engineer, but from my distant memory I have to ask A=are you measuring RMS voltage or Peak voltage.

RMS x √2 = Peak.

So, if you are measuring 230 V and your meter is set to Peak then it will indicate 325V. 240V would indicate 339V.

[billi]

Put a load on it, like an electric heater 2-3kw and then measure it.

my first thought , too

[Hermit]

Hi Justme, sounds like a dud meter or something to me as you say "it reads OK at the inverter". I am thinking that if the inverter accepts the voltage then it must be OK

[Justme]

Hi Justme, sounds like a dud meter or something to me as you say "it reads OK at the inverter". I am thinking that if the inverter accepts the voltage then it must be OK

When did I say that?
The scope reads inverter fine.
Meter reads inverter fine.

[Westie]

I am a mere Mechanical Engineer, but from my distant memory I have to ask A=are you measuring RMS voltage or Peak voltage.

RMS x √2 = Peak.

So, if you are measuring 230 V and your meter is set to Peak then it will indicate 325V. 240V would indicate 339V.

Good point, many cheap multimeters have a peak hold function now... Make sure its not peak holding!

[Justme]

Need a bit more info mate, is it brushed or brushless, if brushed how many sliprings 2 or 3?

Brushless.