---------- .From: James Sketoe <[email protected]> .To: [email protected]; [email protected]; [email protected] .Subject: Re: Toroid Isolation Power Transformers -Reply .Date: 1996年12月12日 AM 12:45..
.The isolation aspect is limited to 60Hz .isolation. The prime power is .ungrounded. It will be fed through the .isolation transformer whose secondary .will be grounded to form a green wire .ground/neutral connection. For this I .don't think I need interwinding screens. I think even when the secondary side is not grounded, but primary and secondary are seperated by three layers of isolation tape that can withstand the high voltage test, The metal grounding shield is also not necessary. .However, I don't quite understand your .comment supporting switch on voltage .peaks. This seems to me to be counter .productive - or am I under a .misconception. I thought I would need a .switch on zero to minimize inrush .current. To avoid the inrush current the voltage must really be swithed on at maximum, think about that voltage and current are 90 deg. out of Phase, with the current trailing. At maximum voltage the current is just zero. If you switch on at zero voltage, the negative current from the previous half sine is missing, the current will therefore rise from zero to twice the peak current for a linear inductivity. As the iron of the transformer will go into saturation at higher currents, the actual peak current might rise to 10 times the peak current. Rene Charton EMC-Manager TUV Rheinland Taiwan
