(ET) [Fwd: Re: Curtis or any generic controller setup]

["Jim Coate" <lists freerangeelectric com>]

Interesting.... I had gotten as far as confirming that both the original
Alltrax design (AXE) and their newer design (SPM) are rated for series and
PM usage. (SPM = Series, Permanent Magnet). In turn I was wondering what
Curtis did differently, but you have found that at least on certain models
they share the same series and PM usage, eliminating that concern.

Back when I drove a converted pickup truck with 9" series-wound motor and
Curtis controller (1221C?), there was an issue where if coasted backwards
and built up a little speed, there would be a sudden lurch. As I
understood it, there was enough residual magnetism in the motor for it to
generate a little power and as it reached the 0.6 volts of the freewheel
diodes they would start conducting and give a little burst of braking.
Learned not to do that as feared it was stressing the diodes (even so the
Curtis eventually died and I went to a DCP controller). Thinking out loud
now if either a controller (series/PM controller or a sep-ex) on an
Elec-Trak would have such issues?


> Curtis 1204 states that it CAN be used with series or PM
> motors. It says to just omit using that A2 terminal if using a PM motor.
>
> ... the Alltrax drop in replacement for the curtis 1204, the NPX
> and AXE series say in bold underline that they can be used on series and
> PM motors.
>