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RELAY QUESTION


 Te> What is the difference between a relay, a contactor, and a motor
 Te> starting  relay?  I ask this because I was ready to buy a motor
 Te> starting relay that  I thought would have worked just fine for my Tesla
 Te> coil control  cabinet (proper voltage and current ratings), but the
 Te> person who was  selling it said that it would not be possible to use it
 Te> as a simple high  current relay, and that I really needed a regular
 Te> relay.
Most "motor starter" relays have built-in time delay thermal overload
protection to allow the motor to draw a large peak starting current for
a certain time (usually adjustable on starter) and kick off if this time
is exceeded due to a mechanical overload on the motor (locked rotor).
Unfortunately, many of the motor starters have electronic timers which
would would get really confused in a hurry with the high RF fields
near a TC. I'd get a "lighting" type contactor, which is really just
a large relay made to handle a high initial current as tungsten lamps
produce when turned on cold. These are expensive, but will probably
last forever. I'd also check out the scrapyards, I've gotten some nice
contactors and other electrical components for scrap metal value!
Brad Alheim

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