Re: Super Series 42220

[James Robinson <NOSPAM@ERIE.NET>]

Maurie Daly wrote:
> ...does anyone know exactly how the Super Series
> control actually controls the power to the motors .
> I assume some  sort of large gate turn off thyristors are used,as this is
> about the only way to apply pulsed power to a DC motor.
> If this is the case , its quite likely that 42220 still has the GTOs but
> doesnt still have the doppler radar unit and the speed sensors on the axles.

Power to the traction motors is controlled by excitation windings in the
main alternator.  The power in the windings is in turn controlled by
thyristors. Since the power is relatively low, the thyristors are not
particularly large. Power to the motors is not pulsed, rather it is
constant DC.

Super Series is the name General Motors gave to the adhesion control
system, and not the total excitation system.  It is mainly radar-based,
but uses transductors to measure the volts/amps of each of the traction
motors to supplement the radar.  Axle speed sensors are not required,
but may be provided to drive the speedometer, event recorder, or slow
speed control (if the locomotive is equipped with one.)  The radar can
be removed or disabled, and the system will work using the transductors
only.  The pulling power of this arrangement will not be as good since
creep control will not be available. (Similar to that of an N class) 
Another option is to replace the General Motors excitation control
system in its entirety with a third party system.