[TowerTalk] Reply - KW3000 with 1/2 inch Drill Motor - Wrongassumption in responses

[Richard (Rick) Karlquist]

Dubovsky, George wrote:
> You will still lose torque with a pwm light dimmer. You will need something like an variable speed drive, where you vary the drive frequency and voltage simultaneously, essentially synthesizing a complete sine wave at an adjustable frequency. I use them on three-phase motors on my lathe and mill, but they are also available for single-phase motors. Not cheap, but less than the Hole Hawg ;-)
> 
> 73,
> 
> geo - n4ua

The idea of the PWM method is that you have full torque when
on, but are not on all the time.  You do lose horsepower, but
not torque, AFAIK.  It's similar to pulsing the ON/OFF switch
on the drill.  I am not sure if there is any difference between
a PWM motor speed controller and a light dimmer.

A variable frequency drive sounds like something for an AC induction
motor.  Most drills AFAIK are AC/DC motors, for which frequency is
obviously irrelevant.

If the above is wrong, someone correct me.  I want to get a
Hole Hawg too, as soon as I figure out how to slow it down.

Rick N6RK