wirewound resistors - how are they made? (and rheostats, same deal?)

I guess nichrome wire wound around a ceramic core, then coated with (maybe?) epoxy. my biggest question: I assumed the resistance wire was originally UNcoated, bare wire, wrapped with each turn touching the next.

BUT

if it IS bare wire, then the makers either must keep each turn from touching the next turn over (with a very small clearance), *OR* the wire is coated -prior- to the winding process. otherwise, the 'resistance per turn' wouldn't be controllable - right? I mean like if one turn, near the middle of a wirewound resistor, was 'shorted' to the next winding mid-turn...

like in these things:

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wirewound03.jpg

thanks for info, guys :-)

bubba here is kind of contemplating making a rheostat...this recipe calls for a 6 ohm, 11.1 amp type (see bottom right of page 2)

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AutoArcWelder.pdf (application/pdf Object)

of course, i have this ol' powerstat, but it's a 5 amp model

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powerstat07.jpg

Reply to
dave
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I've had several damaged wirewound resistors in which I could see the wire. There's a gap between each turn, and the lower resistance, generally the wider the gap because the wire is shorter.

Reply to
James Sweet

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