Re: hamfests, rotors, protection

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mike Harrison by way of Terry Fritz <twftesla-at-uswest-dot-net>" <mike-at-whitewing.co.uk>

On Mon, 29 Jan 2001 07:54:50 -0700, you wrote:

>Original poster: "Matt Skidmore by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <fox-at-woozle-dot-org>
>
>i went to a small indoor hamfest over the weekend and picked up a few
>goodies at a very low price, but i had some questions about adding them to
>my coil.
>
>i got 5 wirewound resistors for 50 cents. these are 2 ohm and i'd guess
>about 75 to 100 watt each. a gree ceramic type. i dont have the money to
>build a nice NST protection filter so i was thinking about using two of
>these resistors in paralell accross each leg of the NST, with of course, a
>safty gap. i know this isnt the best solution but wanted some comments,
>maybe an idea of what to do with that extra resistor. they're only 2 ohm,
>is that enough?
>
>also while i was there, someone gave me a brand new sync motor. i cant
>tell if the hp is 1/3, 1/30, or 1/300. its 900 rpm. i wanted to know what
>the calculation is for creating a rotor for this. how big does the
>rotorneed to be and spacing of the electrodes. this motor has 3 wire,
>yellow, red, and green. i assume red is hot yellow is the other side and
>green is ground, but whenever i plug green to ground the motor stops and
>is quite hard to turn. i was thinking that maybe green is the start
>circuit? when i plug it in i usually have to give the motor a spin before
>it starts. so i read that some motors have a start circuit.

It probably needs a start or run capacitor - depends on the exact
motor type. You should be able to guess the HP rating by comparing the
physical size with other motors in a catalogue or on mfr's websites,
which would probably also give an idea of the cap size.