[TowerTalk] Re: M2 controller for Prop Pitch motors

[K7GCO@aol.com]

In a message dated 8/3/00 4:32:15 PM Pacific Daylight Time, K6myc writes: 

 Ken, Please put the following note on Tower Talk, Thanks.
 
 When controlling prop pitch motors with M2 RC2800 controllers, you must 
short out the rear brake coil. Without the short, motor current runs through 
the coil creating a strong magnetic field that will close the reed switch. 
This prevents the magnet spinner from having any effect on the reed switch. 
The result is no pulses will be fed back to the controller and the 
microprocessor will turn off the motor voltage in the flick of an eye. 
 By shorting out the coil, no stray magnetic field is created and the magnet 
spinner can do its job by closing and opening the reed switch once per 
rotation. 
 
 I hope this clears up the mystery of the brake coil.
 73, Mike Staal, K6MYC 
<< 
 
In a message dated 8/3/00 3:17:19 PM Pacific Daylight Time, K7GCO writes:
  << Mike:  
  For your information  k7gco
  
  In a message dated 8/3/00 1:42:10 PM Pacific Daylight Time, km6iu@jps.net 
writes:<< 
   My notes have the brake coil at 0.037 ohms. The two field windings are 
each close
   to 0.095 ohms and in series with the brake winding.   Shorting the brake 
coil
   will eliminate this in-series resistance----- but it also eliminates some
   "interfence" with the M2 control box--not sure why/how-- but without the 
short
   some have had much grief. If your numbers look the same pass them on.  
larry
   
   K7GCO@aol.com wrote:
   
   > In a message dated 8/3/00 1:14:22 PM Pacific Daylight Time, K7GCO writes:
   >
   > << In a message dated 8/3/00 4:24:25 AM Pacific Daylight Time,
   > clive@gm3poi.prestel.co.uk writes:
   >
   >  <<
   >   Does anyone know the reason why it is suggested that the brake coil on 
a PP
   >   has to be shorted out even though the brake unit is no longer there. 
This
   >   appears in the documents from M2 on installing a reed relay with the 
RC2800
   >   control unit. I've been unable to get a reply from M2. 73 Clive GM3POI
   >    >>
   >  If the brake is not in there, shorting out the coil however small it is 
just
   > lowers the resistance of the entire circuit.  I'll measure it out of
   > curiosity  K7GCO >>
   >
  

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