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Originally Posted by Al Skierkiewicz
Greg et al,
The reference in Kevin's post: http://www.enigmaindustries.com/links.htm lists the 884 as 120Hz and the 883 as 2kHz, hence my confusion. (being around for a long time does get in the way.) Greg, are you in a position to check rise time where you are right now?
Jim,
(I am confused and keep calling you Rick) You tell us that the motor is unloaded but it is connected to the FP gearbox. That is a load. The numbers in your table suggest the large amount of friction present at low speeds in that FP gearbox. At low speeds, a motor still must overcome internal losses due to friction, brush pressure and magnetic influences. On the FP motor in particular, there are only three commutator segments which means three windings. Depending on the duty cycle, energy may only be supplied to the motor for a small portion of the brush/commutator cycle at low speeds. If analyzed, you may find that current is only flowing to one winding at a time instead of two. (two gives better torque/output/higer current) In contrast, the drill motor has several windings/commutators and the spec sheets illustrate the difference in these two motors. Ironically, the graph you displayed in your earlier post is a typical charge current graph of an inductor. This may indicate the effect of the duty cycle vs. inductance or not. |
Ok we have all come to the consensus that in order to figure out whether or not the victors are linear or not, we must measure duty cycle.
Exactly how do you calculate the reactance vs. time of an inductor with a square wave input. I know how to do this with a sine wave, but a square wave is much more complex. Would you model the first 10 or so sine components of the square wave? Is there a simpler way?