600-up Amp controllers necessary at all?

[rib33024]

Originally Posted by scottyb

Sergio Rocks
Continuing to educate us all on electronic gizzmology

This is so true

[NoleFan4Ever]

Well I have read over this and studied the facts and agree to its contents for dissemination.

[NoleFan4Ever]

Originally Posted by dundeebarnbuggy

Would be great if he added a little more, explaining how this all comes together in a sepex cart.

Yeah, Sergio, can we get some more info on how this corresponds to separately excited systems....

[Sergio]

Here are some thoughts about construction characteristics in Series and Sepex Motors that make them in general better suited for certain applications.

The Motor Armature is designed to generate a certain number of mV per revolution based on the magnetic flux created by the current flowing through the Stator/Field coil.

In a Series Motor, the same current that flows in the Armature also flows in the Stator/Field coil so those parameters are "baked" in the motor design and construction.

Separately Excited or Sepex Motor Controllers have 2 independent driver outputs.

The high current Armature driver is a single direction output similar to a Series Motor and benefits from the same "flywheel" effect the rotating Armature provides that multiple the battery current when operating at less than 100% throttle.

The lower current Field coil driver is a bi-deractional output that can vary the field current in order to help regulate the motor torque and speed.

Since the Series Stator coils carry the same high current as the Armature, they don't need many turns to generate a strong flux field, so normally round or flat heavy gauge wire is used.

That heavy gauge wire helps to dissipate and reduce the effect of heat on the Stator coil during low speed high torque demand periods.

The Field coil on a Sepex motor is designed to operate at lower currents (less than 30 amps typically) so it uses a lot more turns of thinner gauge wire.

The resistance of a Sepex motor Field coil can greatly increase during hot operation which limits the maximum current that can flow through the field, reducing the flux produced and the motor ability to develop torque.

Typically Series motors have more consistent torque under prolonged low speed high torque operation that causes a Motor to get hot.

Sepex motors can also be effectively used for braking and even return some of the energy created by Regenerative brake back into the batteries.

Modern Controllers like the Alltrax XCT take advantage of the Sepex motor flexibility and provide different Field and Armature parameters based on rpm feedback received from the speed sensor.

You also have speed/throttle curves that can be adjusted to provide optimum cart control under your most common driving conditions.

[yawood]

Thanks Sergio,

We need you to have Xmas more often so that you have the time to provide us with these more in-depth dissertations.

Cheers.

[NoleFan4Ever]

Yes, thank you Sergio!

[dundeebarnbuggy]

Thanks also.