From rb.keele@verizon.net Thu Dec 25 18:03:07 2003
Subject:Re: Speed Control Pedal

Thank you, Dan.

You are right that these motors don't like low voltage. Generally, these motors are a variation of synchronous motors and want to maintain their design speed. One way to do it, in a safer manner, is to vary the frequency while maintaining the line voltage. The Hampton kit probably is achieving this by skipping power cycles on the power line. Your thought with the 555 and the SS relay should also be able to achieve it.

Another solution would be to replace the motor with a DC motor which would then be easy to control Still another solution, which I would prefer trying, would be to replace the motor with a stepper motor. This type of motor maintains its full torque and can be continuously varied from stop to full speed.

Ron

----- Original Message -----
From: Dan S
To: CloneWheel@yahoogroups.com
Sent: Thursday, December 25, 2003 5:02 PM
Subject: RE: [CWSG] Speed Control Pedal

Ron, thanks for turning my cryptic (but well founded) concern into bite
size chunks all could understand.

There's another problem in this potential setup - Leslie motors are
brushless and brushless motors really don't like to have their voltages
varied. I have heard from many Leslie experts and fanatics that the right
way to do this is varying - and this is where I'm fuzzy, either the
frequency or the phasing of the AC - but NOT the voltage. The end result of
using dimmers, rheostats, etc. is the motor burns out.

Perhaps it takes a long time before that occurs, and maybe the cost of
replacing single speed Leslie motors is worth it. I myself plan to either
purchase the Hampton kit for $250 or try wiring my own version, using a 555
timer on a nice solid state relay I've inherited from Ben Kuris Labs.

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