Re: RE: (ET) snow blower

["Bob Murcek" <RMURCEK geisinger edu>]

The PTO relay in the tractor provides the switching for a braking 
function, right?  So I'm wondering why it wasn't used on the snowthrower.  
Does the thrower have a series motor?  Does dynamic braking work with a 
series motor?

>>> Shawn C Passwater <Passwater_Shawn_C cat com> 10/23/2001 12:25:37 PM 
>>> >>>

Joseph,
I use to work for a Automated Guide Vehicle company. The AGVs used a DPDT
relay and a single pole relay that would parallel a resistor across the PM
motor for the lift motor and drive motors. The drive resistor was sized to
stop the vehicle within the distance of the bumper. The dynamic braking was
needed in case the drive motor or lift motor brake would fail.  This same
resistor was used to soft start the lift motor. The DPDT relay would
energized with the resistor in series with the
lift motor for .5 -.7 secs. The control would  energize the single pole
relay jumping out the resistor (resistor and spst was in parallel).
I can get you  the wattage and resistor sizes that was used for 24 and 48
volt AGV's.





Shawn Passwater
Caterpillar