RE- Secondary wire & insu
Subject: RE- Secondary wire & insu
Date: Wed, 04 Jun 1997 08:07:00 GMT
From: robert.michaels-at-online.sme-dot-org (Robert Michaels)
Organization: Society of Manufacturing Engineers
Apples and oranges, again. (Why always those particular fruits,
why not, say, persimmons and mangos)? I sort of agree with Mr.
Skrocki, and I sort of don't.
-- Making a space-wound coil using a closed loop (as a
spacer) with a weight attached is effective, but I'd
scarcely say it is "easily" done. In fact it precludes
any machine or power-driven winding of a coil.
In my experience, the closed, weighted loop is best
made itself of magnet wire.
-- To compare wire enamels of 1907 (or whenever) to those of
1997 is truly to compare persimmons and mangos.
"Back then" they were little more than furniture
varnish, their high-frequency electrical characteristics
were ...?!?!?. Today, wire enamels are specially
designed and formulated for optimal electrical
characteristics; it's a whole technology in itself.
-- In all but the highest powered Tesla coils, the volts-per-
turn of the secondary is apt to be below the breakdown
voltage of the wire enamel.
Consider: A 500-Kv coil having a thousand turns
in it's secondary (Love those round num-
bers!). That's 500-volts/turn.
Which means, the wire enamel must withstand
250-volts. Not a major challenge for today's
wire enamels. Comprendo, compadre - 250-v.?
(Hint: Adjacent turns have =two= layers of
wire enamel between them, one on each of the
two wires: 500/2 = 250-volts. )
Wire enamels are available in a wide variety of types (and
prices!) and one must specify knowledgeably.
- - - - - - - - -
This is not to say Mr. Skrocki (or Mr. Curtis) is wrong. Not
at all. (If nothing else, DCC wire really looks cool when
wound into a coil -- and I favor gutta percha myself! - ooohh!).
I'm just here to say that wholesale dismissal of the
entire field of modern wire enamels may be a bit hasty.
(That, and use a weighted loop of =wire= when space-winding
Keepings those windings
straight, in -- Detroit, USA
T> Begging to differ here, most small commercial induction coils were
T>wound with bare wire and many a tesla coil have too, you just have to
T>space the wire and that is easily accomplished by making a loop of
T>thread the same thickness as the wire you are using and put a 1/4 to
T>1/2 oz. fishing sinker on the loop and wind the coil with the loop
T>between turns it will keep the spaceing. The insulation on the wires
[ ... ]
T>turns thus insulating the coil better. As a mater of fact to quote
T>Thomas Stanley Curtis in his "High Frequency Apparatus" he states;
T> "The conductor for the secondary windings of all types of
T> oscillation transformers should be of soft, pure copper wire.
T> The insulation may be of cotton or silk but NOT of enamel. The
T> use of the later for high frequency secondaries has given the
T> author great dissapointment in the construction of several large
T> and comparatively expensive coils. The insulation on the wire is
T> of no value whatever except to provide a mechanical separation
T> for the turns of wire and to form a base or support for whatever
T> insulating substance is applied to the wire subsequenty."