OK. my ignorance is showing on this question. I have used both in different situations over the years but what is the difference in controlling electric motors?
On the pen turning web site, (IAP) the question came up about using a rheostat for controlling the speed of non ESV motors. I thought it would be disastrous, but some say it is possible. No one came on and talked the technical terms, but I personally didn't think a potentimeter/rheostat could control a large motor like that.
So what is the difference in using a 20 amp variable transformer VS a large rheostat to control the speed of a lathe motor. (We are talking about 1 hp or less motors on small lathes.)
BTW, I tried the 20 amp Variac on my Grizzly lathe. It would not do much of anything until enough voltage came through to make it suddenly start turning at about 450 rpm, where as 600 is the slowest it will go with normal 120V. I tried it once (had to do it) and won't do it again - too much buzzing/humming like it it trying but not doing anything. At 110-120 it works normal.
On the pen turning web site, (IAP) the question came up about using a rheostat for controlling the speed of non ESV motors. I thought it would be disastrous, but some say it is possible. No one came on and talked the technical terms, but I personally didn't think a potentimeter/rheostat could control a large motor like that.
So what is the difference in using a 20 amp variable transformer VS a large rheostat to control the speed of a lathe motor. (We are talking about 1 hp or less motors on small lathes.)
BTW, I tried the 20 amp Variac on my Grizzly lathe. It would not do much of anything until enough voltage came through to make it suddenly start turning at about 450 rpm, where as 600 is the slowest it will go with normal 120V. I tried it once (had to do it) and won't do it again - too much buzzing/humming like it it trying but not doing anything. At 110-120 it works normal.
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