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.
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. Thanks for the comments. I apoligize for the delay in getting back to you. jgs >>> Chris Dupres <[email protected]> 12/05/96 03:41am >>> Hi Jim. You wrote: > Looking for info on using toroid transformers for power isolation in > applications up to 10 kVA. Their advantages are great - half the > size, half the weight, and less costly. I understand they have higher > inrush current, but I don't know how much. Looking for advice. I'm not sure about their use as IsolationTransformers, I always use E cores with separate bobbins for that. The Toroids MUST have earthed interwinding screens if used for isolation. Inrush currents can be very high, it's best to switch them with a Peak Voltage switching solid state device (Not zero voltage) if you can, or use circuit breakers with an 10:1 instant / long term trip ratio. They are much better at tranferring EMI from the secondary to the primary as well, they can't be used as an adjunct to filters as E cores can. Thats a tuppence worth.. Chris Dupres EMC Specialist. VG Microtech. [email protected] tel +44 (0) 1825 761077 fax +44 (0) 1825 768343 'Opinions expressed are personal, not necessarily Corporate'
