[TowerTalk] SteppIR

Jim Thomson jim.thom at telus.net
Sat Feb 28 20:46:24 EST 2015


Date: Sat, 28 Feb 2015 11:02:00 -0600
From: Patrick Greenlee <patrick_g at windstream.net>
To: towertalk at contesting.com
Subject: Re: [TowerTalk] SteppIR

That is why it is called a stepper motor.  Its motion is stepwise, not 
continuous, think digital not analog.  If the steps are small enough and 
are taken rapidly enough you can closely simulate the smooth turning of 
an analog motor. Of course an advantage of the stepper motor is you can 
keep track of where you are by counting the steps and not need a shaft 
encoder or other method of tracking position in a system driven by an 
analog motor. Stepping motors make position servos simpler.

Patrick   NJ5G

##  whats wrong with installing a shaft encoder on the plane jane DC..or AC
motor?    That’s what K7NV  does on his prop pitch conversions..and works
slick..simple concept, easy mod to any motor.  Its all fed to the Green Heron
box...which is a modified RT-21. 

## The GH box for the small PP  only puts out one dc voltage, that’s it.   The
oem 28 vdc motor in the  PP uses the PWM  in the GH box to control the speed
of the PP.   So that way you can ramp up and ramp down...sorta like  a
8 speed automatic transmission in a car.   .1 deg readout, pre sets, the whole
9 yards.

##  PWM works slick on DC motors.  It allows you to slow the motor way down,
without losing torque..... like you get if you try and slow  down a motor by reducing
its voltage. 

Jim  VE7RF  



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