40 mil LDPE and 5kv Transformers?
From: richard hull [SMTP:rhull-at-richmond.infi-dot-net]
Sent: Wednesday, April 08, 1998 8:22 PM
To: Tesla List
Subject: Re: 40 mil LDPE and 5kv Transformers?
At 08:09 AM 4/8/98 -0500, you wrote:
>From: Steve Falco [SMTP:sfalco-at-worldnet.att-dot-net]
>Sent: Tuesday, April 07, 1998 5:55 PM
>Subject: 40 mil LDPE and 5kv Transformers?
>I am building some capacitors using .040" LDPE. I was originally
>planning on building two units and putting them in series to get an
>adequate voltage rating.
>But now I find that the H&R trannies I am using really only put out half
>the voltage they are spec'd for, i.e. really 2.5 kv each (without
>resonating caps), rather than 5 kv (with resonating caps). So, I am
>wondering if a single layer of .040" LDPE will hold with two trannies in
>series (5 kv total voltage applied). This would let me use 1/4 the
>amount of plastic, which is worth considering.
>If I assume 400 volts per mil of LDPE, then 0.040 * 400 = 16 kv which is
>slightly more than 3 times the applied 5 kv. So, there would appear to
>be a reasonable safety factor, even allowing for peak voltage.
>Any opinions out there? Will one layer take it or should I go for
>multiple series caps?
> Steve Falco
Series caps are always best, but the .040 poly whould do OK provided you
hold your power down to under 2KW. I have successfully used .040 up to
7.5KV when holding power under 1KW. I suggest a flat plate design for lower
Richard Hull, TCBOR