Need adivse about stuff....long sorry

[Blake McCully]

Hi all. I have a question about electrical/electricity and stuff. The only thing I know about electricity is flip a switch and a light goes on or off. Plug something in the wall and it works. So, now to my question.

A carver friend of mine bought an off brand lathe a while back and has started playing. I talked to him last week and he told me that an electrician friend of his put a rheostat(sp) on his lathe. Apparently on his switch. He told me he hasn't tried it yet but will. I guess what he was trying to get was variable speed for his lathe. My first reaction was, that won't work will it? I didn't tell him that though. But after I thought about it, I thought, well why won't it.

First, I have a couple of old jet minis with the manual belt speed change. So, suppose one were to put the belt on the highest speed, and had a rheostat to turn it on, would that work as a variable speed control? Has anyone tired it or thought about it? If it won't work, how come?

If if doesn't work, and I don't think it will but am not sure why, and someone tries to explain it to me, please keep in mind that I am extremely electronically challenged.

Probably won't do anything like that anyway. I'll be getting a lathe with EVS at some point anyway. Just thought I'd like to see what the group concensus is.

Later.

[Don Baer]

A reostat is a type of auto transformer then the way it works is it's a variable transfomer. They have often been used in stage lighting circuits to control the brightness of the lights. What they do is change the voltage. They will cause an AC motor to run slower but with a result of a loss of torque. to firther exasperate (sp??) the problem a single phase motor has to reach 2/3 of the maximum speed before the centrifical switch that controls the starting capacitor & starting windings. The starting windings are NOT designed for continuos use. If the motor runs below 2/3 speed for extended time he wil let out the smoke and need a new motor. The proper way to have variable speed is to use an inverter anda 3 phase motor. I did a thread on applying variable speed drive to lathes a while back. here is a link to the thread.

http://www.sawmillcreek.org/showthread.php?t=39536


Edited to insert this thought.
The motor on the off brand lathe may have a cheap universal motor (one that has brushes and can run on either AC or DC. If this is the case he won't burn up the starting windings since it doesn't have them but he still will have reduced torque. Your Jet lathes have single phase induction motors and what I said above only applies to induction motors.

[Blake McCully]

Thanks Don,
That was a very precise and, for me, understandable explanation. Like I said, I didn't plan on doing anything like that, but was just curious why it would or wouldn't work.

Thanks for the great explanation.

[Charles E. Martin V]

That was a great explanation. I'd also like to throw in the "don't play with electricity" warning for those that may not know what they're doing.

[Randy Moore]

I will add my bit of knowledge about electricity.

Pay your bill on time:)
&
Don't play with it 'cause it will KILL you:eek:

[Glenn Hodges]

I would like to add, "Don't pee on electric fences."

[Charles E. Martin V]

I agree completely with Glenn. Also note electric fences may sometimes be hidden in bushes.

[Ken Fitzgerald]

I'll add some advice. If there is a heavy dew and you have to walk through tall grass.....turn off the fence.....don't try to step over it..........

[Blake McCully]

I would like to add, "Don't pee on electric fences."

Yeah, don't spit on them either, damhikt:( :eek: