Inverter Voltage

[ditchcrawler]

A friend of mine has just rung me to say that he has just fitted a new 350W Sterling Quasi sinewave inverter. Measuring the output voltage with a meter it was only reading 180 volts. Now this is something I have never tried but we are wondering if its faulty or is it the crap waveform confusing the meter?

[WotEver]

The quasi bit is confusing the meter.

[nicknorman]

Wot wot said.

[Loafer]

Wot wot said.

 

Wot wot?

[nicknorman]

Wot wot?

The wot just above my post!

[Loafer]

The wot just above my post!

 

I thought you'd say 'Wotever'!

[nbfiresprite]

The voltage will rise to 230volts as soon as you drawn power from it.

[nicknorman]

I thought you'd say 'Wotever'!

Sorry!

[WotEver]

Wot?

[ditchcrawler]

Only one saying something different

[Richard10002]

More Wots than a light bulb!

[WotEver]

Only one saying something different

Yeah, but that's cos he/she is wrong

[ditchcrawler]

Yeah, but that's cos he/she is wrong

Its a he, nbfiresprite. I do wonder if it runs at a lower voltage with no load? but I doubt it at that price.

[cuthound]

I suspect the reason why it is reading low voltage is because of the shape of the "quasi" waveform.

 

Most meters are designed to read the rms value of a sinusoidal wave. The "quasi" waveform will be a modified squarewave, if your lucky. Probably looks like three building blocks for each half wave, one placed centrally on two side by side, rather than one half of sinusoidal wave.

[WotEver]

I suspect the reason why it is reading low voltage is because of the shape of the "quasi" waveform.

That's absolutely the reason, as I said in post 2.

[ditchcrawler]

Thanks all that is also in line with our thoughts but it is something I have never had cause to check.

[WotEver]

Thanks all that is also in line with our thoughts but it is something I have never had cause to check.

Without buying a silly expensive meter the only way to check it properly is with a scope. As said, it'll look like 3 building blocks.

[cuthound]

That's absolutely the reason, as I said in post 2.

I know you did Tony, however the post had begun to drift with suggestions that the invertor may run at a lower voltage offload, so I thought I'd kill two birds with one stone by confirming it will be the shape of the waveform and explaining why.

[nbfiresprite]

Its a he, nbfiresprite. I do wonder if it runs at a lower voltage with no load? but I doubt it at that price.

Expect that I'am not wrong. I have noted that quite a number of lower rated inverters (Under 500watts) with no load applied do show a voltage reading of around 180volts and when a load is applied the voltage reading increased to 230Volts. Most of these inverters are made in the same factory, Just a different label or case.

Edited February 8, 2016 by nbfiresprite

[nicknorman]

Expect that I'am not wrong. I have noted that quite a number of lower rated inverters (Under 500watts) with no load applied do show a voltage reading of around 180volts and when a load is applied that the voltage increased to 230Volts. Most of these inverters are made in the same factory, Just a different label or case.

But the question is, does the voltage actually increase or is it just that the load helps to make the waveform more sinusoidal? And what exactly is the definition of the voltage of a non-sinusoidal waveform?

Edited February 8, 2016 by nicknorman

[WotEver]

But the question is, does the voltage actually increase or is it just that the load helps to make the waveform more sinusoidal?

Yup, the latter.