? about EVS speeds

Frank Fusco

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Mountain Home, Arkansas
On my new Grizzly G0632 lathe, with EVS and a digital read-out, I notice that when a load is applied the speed increases 10 to 20 rpm. I like that because it indicates to me that the motor is sensing the load and kicking in more power to meet the demand.
Now: Am I kidding myself? Is this normal with EVS?
 
Dunno the answer for you Frank, but I've got a question...

Aren't you supposed to be watching the cutting edge of the tool when you're turning, not the fancy red numbers on the digital readout? :p
 
I would think that the control would pump more current to compensate for the increased load...therefore adding more torque/power. RPMs would be adjusted by changing the frequency...No? Should not happen to increase power, IMO. :huh:
 
On my new Grizzly G0632 lathe, with EVS and a digital read-out, I notice that when a load is applied the speed increases 10 to 20 rpm. I like that because it indicates to me that the motor is sensing the load and kicking in more power to meet the demand.
Now: Am I kidding myself? Is this normal with EVS?

What percentage of the set RPM does that equate to, is it significant?
In an ideal world, as has been said the RPM should just stay constant-ish but I suspect that in this real world of compromise the in built programming is a little wide in its limits and is over compensating, it is most likely the perception of rpm slowdown (due to rotor slip?) that is triggering the response and it appears to be a little heavy on the gas pedal in compensating this, I take it it backs off again when the tool load disappears.
 
Frank, on all my EVS lathes, the motor has increased its power output to compensate for load, but I have never seen the rpm indicator change as a result. But as has already been mentioned, I would not worry about it. When I had the Poolewood, the rpm was indicated by a digital readout. I would tell a student to go to 700 rpm, and they would fuss with the dial for a couple of minutes trying to get it exact! :huh: I would then explain that anything within 50 rpm was well within the target speed.

Bill
 
Frank, on all my EVS lathes, the motor has increased its power output to compensate for load, but I have never seen the rpm indicator change as a result. But as has already been mentioned, I would not worry about it. When I had the Poolewood, the rpm was indicated by a digital readout. I would tell a student to go to 700 rpm, and they would fuss with the dial for a couple of minutes trying to get it exact! :huh: I would then explain that anything within 50 rpm was well within the target speed.

Bill

This was on test runs at the very lowest settings. Depending on how I held my mouth, it would be 120 to about 300 rpm.
 
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