Technical question about SepEx controllers.

[JohnnieB]

Does anyone have a block diagram and/or a technical description of how the reversible, low amp, controller that feeds the field windings works?

Attached is a block diagram for a Curtis 1204 series drive controller that can more or less be used as a generic example to explain how series controller work, but I have yet to find anything similar for a sepex drive controller and would love to have one.

I'm speculating, but I'm pretty sure the high amp PWM to the Armature is roughly the same as what is found in a series drive type controller, but the low amp one the feeds PWM to the field windings somehow manages to send amps through the field winding in one direction for Forward and in the opposite direction for Reverse, and was wondering if something like complementary sets of P-channel and N-channel MOSFETs were used.

Any info or pointers to where info can be found will be most appreciated.

[BobBoyce]

Originally Posted by JohnnieB

Does anyone have a block diagram and/or a technical description of how the reversible, low amp, controller that feeds the field windings works?

Attached is a block diagram for a Curtis 1204 series drive controller that can more or less be used as a generic example to explain how series controller work, but I have yet to find anything similar for a sepex drive controller and would love to have one.

I'm speculating, but I'm pretty sure the high amp PWM to the Armature is roughly the same as what is found in a series drive type controller, but the low amp one the feeds PWM to the field windings somehow manages to send amps through the field winding in one direction for Forward and in the opposite direction for Reverse, and was wondering if something like complementary sets of P-channel and N-channel MOSFETs were used.

Any info or pointers to where info can be found will be most appreciated.

Yes, the output is a pair of N channel FETs and a pair of P channel FETs in an H Bridge configuration. They are usually pulse width modulated by a processor output and driver on the negative side only. The positive side is usually not PWMd, just turned on by another processor output and driver.

Bob

[JohnnieB]

Thanks for the info. I was in hopes you'd respond to this.

I hadn't given it much thought other than F1 and F2 changed polarity to change the direction the armature turned, until a couple days ago when a someone had a XCT500 that gave a Motor Field Failure error in Forward, but ran normally in Reverse. http://www.buggiesgonewild.com/showthread.php?t=162916

I take it the N-channel devices with a PWM output is used for forward and F1 would be negative.