🚀 go-pugleaf

Tim Deagan (timd@fenian.dell.com) wrote:
: They were manufactured by SINGER and are labeled;
: Kearfot Variable Reluctance Stepper Motor
: They have four leads;  Black, Brown, Red and Orange
: RE, OR and BR all have 32 ohms between any pair, BL has 18 ohms
: between itself and any other lead.  (3 phase stepper?)
: 
: Sequential stepping of the OR RE BR leads does not do anything
: but make the shaft vibrate.

All VR steppers have at least 3 windings.  They don't have any
permanent magnets in them, and are polarity insensitive, like
a solenoid.  My guess is that the black lead is the common.
So putting current from the black lead to the other leads in some
sequence should move the motor.   Drive currents are either
on or off, (unlike the driving a Permenent Magnet stepper in
two winding (4 wire) mode).

Driving any one out of the three windings should cause the rotor to 
step to a postion, and switching the drive to another winding will cause 
it to step one unit either way.  You can get more torque by driving
two out of three windings at the same time.

One way to think of a simple VR stepper is 3 solenoids hooked up to
a crankshaft, arranged like a radial aircraft motor.


Mark Zenier  markz@ssc.wa.com