# Generator output voltage too low and then increases with additional loads



## SmackDub (Sep 5, 2015)

Hi All,

I have a generator which is causing some issues.

The output voltage is 150 volts & 50 hz with no load.

It should be 230 volts & 50 hz.

When the load in increased by adding a 3kw kettle the voltage increases to 190 volts and is drawing about 12 amps.

I plugged in another load (an iron) and the voltage increased some more.

I would have expected the voltage to stay constant or at least decrease.

When the generator is idling the voltage can be manually increased by pushing on the throttle,the frequency also increases.

Any ideas what could cause this or how to resolve it

I have attached some photos.

Perhaps someone can explain to me what I am looking at?

Thanks for your help


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## KRE (Nov 29, 2011)

What country are you in? The data tag just gives engine info, and I need to see the alternator tag or at least know if your application is in fact 50 hertz. For 230VAC is normally a 60 hertz voltage, most 50 hertz would be 220/380. If your in the states or similar, your freq is to low which is why the voltage is also low an increases with load. A cap excited unit will do that when out of it's freq(hertz) range, but you will burn it up shortly operating it like that for the alternator cooling system will not dissipate the heat fast enough, if out of it's design speed range. How are you checking the hertz?


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## hiqman (Sep 6, 2015)

SmackDub said:


> Hi All,
> 
> I have a generator which is causing some issues.
> 
> ...


I am scare about the eletrical but this is a new lesoon for me. Thanks


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## SmackDub (Sep 5, 2015)

Hi Kre,

I am in the UK.

The RMS voltage here is normally 230 volts with a frequency of 50 hz.

There is no tag on the alternator.

I checked the Hertz with a fluke meter and the current with a clamp on.

Looking at the alternator there does not appear to be a lot of electronics inside.

There is a big starting capacitor and a diode bridge rectifier.

So I am unsure if any of these components could cause this issue?

Any advice is much appreciated.

Thanks


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## KRE (Nov 29, 2011)

Either will cause your issue. With the Fluke check the capacitor and diode bridge rectifier both. If you have a cap function on the Fluke use it then read the specs that should be printed on the cap. The bridge rectifier will have an indicator mark of some kind on one corner, that will be the DC + . The next corners either way will be A/C input with the DC- between them on the corner opposite the DC+. I would think one or the other is defective as your building voltage, an the voltage is following the hertz. Let us know how it works out.


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