measuring current

[stag]

 How can I measure AC & DC current from my wind turbine? My clamp meter only measures AC current on one of the three phases at a time. Can I calculate the total current from this by simply multiplying the single phase by three. also would the DC current be this figure plus about 40%. I'm guessing that it's not that simple. Any help would be much appreciated. No complicated formulas please.

[tanner0441]

Hi

Why do you want to measure the AC current? For the DC side a simple ammeter with enough range to cover what you want, I put together a box with a volt meter and ammeter just for checking my solar and wind setup using a couple of analog meters so I can follow any changes without it looking like a fruit machine. I have an analog AC ammeter I bought in error so they are available. I think they were less than £10 each.

Brian

[Flux]

Not desperatyely accurate measuring ac in one phase to derive the dc charging current but if you want to try it and you have an air gap type alternator then the dc will be about 13/10 x the ac figure.

For iron cored alternators running with significant reactance there may be overlap in the rectifier and the figure will be  a bit different but even so it will be in the ball park. Don't go kidding yourself that it will be about 3 times phase ac current, it won't.

The only real way to get good results is with a mean reading dc meter but the ac clip on will give an idea.

Flux

[stag]

 Thanks for the advice guys. I will get a DC ammeter. I have built a turbine based on info from Hugh Piggotts' books,using recycled materials(microwave magnets etc. idea from Ed at windstuffnow) So I am testing output so as to know what to hook it up to. So far it has done a good job of charging very flat 12v batteries and rode out 2 gales with 50 mph gusts. The cost was minimal.  Pete.

[tanner0441]

Hi

I bought my ammeter from Ebay 4in scale, moving coil, 15A full scale, internal shunt.  I have a couple of DC clamp meters both SnapOn and I am not impressed seem to spend more time nulling them out than using them.

Brian

[joestue]

no formulas needed for dc current.

take a 6$ 199.9mv dmm and measure the milivolts across 1 foot of 10 awg wire.
1mV = one amp.