Gents,
Having a bit of a brain meltdown today ..
What's the formula for Ip on a 400V to 110V stepdown transformer in terms of Is, VP, Vs? And is it the same for a centre tapped output?
Gents,
Having a bit of a brain meltdown today ..
What's the formula for Ip on a 400V to 110V stepdown transformer in terms of Is, VP, Vs? And is it the same for a centre tapped output?
The design will be more or less loss-less, or at least losses will be 10% or less.
sp take secondary amps times secondary volts - and if there are 3 outputs then treat them as 3 singles.
(so 55-0-55 every amp between the two lives is 110 watts. ,if you have 3 lots of 55-0-55 each drawing an amp, then you have 330watts..
And same for primary/ If you had one winding with 400V between the ends, then the winding current would be not quite 1/4 of the 110V load currents.
But if you have 3 windings, delta style then as each supply line is covering 2 windings at 120 dedrees, a quick star- to delta conversion shows you that the supply line current per phase is 1/3 of 1/230 of the total wattage.
where cos of 120 degrees = - cos 60 degrees = 230/400 approx
Then add 10% for losses, and use a slow breaking MCB for inrush.
Mike.
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