Re: Transformer calculations app
An update, my 1st 'proper' transformer wound using my app for the calculations:
I entered the size of the core (width of E plate tongue x height of lams stack) into my valve amp power transformer program and then added the windings I required (for taps, leave the current required blank)
The HT has multiple taps 0-120-220-360v @ 160mA, a bias supply of 50v @ 10mA and 2 x 6.3v: one for 3040mA (enough for 4 x EL84) and 3000mA (I entered these at 6.9v to account for the voltage drop under load). I plan to add a voltage drop feature to my app to calculate this based on the length of wire.
The transformer laminations/hardware were kindly donate from a solid state amp (a Peavey 80 watt combo, I picked the amp and 2 guitars including a 1960s Japanese model for £20 on Gumtree a couple of years ago)
Weighs in at 5lb 2oz / 2.3kg
I measured the ac voltages with no load on the HT and bias, today my mains voltage was a wee bit lower at 235v (should be 240v)
0-120-218-359 and 48.5v
So close enough, might have been spot on if the mains was at the usual 240v.
On the heaters side, I measured the ac voltages without a load and with the load of a single EL34 drawing 1500mA (as per data sheet)
1) 6.87v no load and 6.3v under load
2) 6.86v no load and 6.2v under load
photos attached
Doug
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