On 27 Mar 2005 05:35:08 -0800, wrote:

These paragraphs are from an article about a homebuilt hybrid car in
Mother Earth News.


"Any project fresh off the drawing board has its share of problems, and

the Opel hybrid was no exception. When David pressed the accelerator
for the first time, he got a 300-amp surge which melted his relays. So
he searched his graduate texts for the answer ... and finally found it
in-of all places-an old high school physics book: A pulser was
necessary to "chop" the current flow and prevent a heavy initial draw
to the drive motor.


As Dave explains it, "The motor will always have full voltage and full
current, but the pulser makes it 'think' the voltage and amperage are
cut down to about 1/4 of what's actually available. With this
gadget-which is simply a combination of a reworked car generator and an

old fan motor-I can keep the draw within limits and effectively control

the car's acceleration . . . without sacrificing the maximum current or

voltage that's necessary for high-speed driving. I could have achieved
the same results with a commercially available FCR control ... but one
of those units would have cut my power slightly, and cost in the
neighborhood of $800! I can build my own device for about $25, and I
can fix it myself if it breaks!"


Boyntonstu
Well, since he said generator and not alternator it could mean that he
uses the fan motor to drive the generator and uses the commutator in
the generator to provide the switching for his pulser. When he speaks
about his pulser and the motor getting full current and voltage what
he means is that the power to the motor is switched on and off. The
motor will average the power delivered in pulses to torque and rpm. So
the lower the on time of the pulser setup the slower the motor speed.
The speed drops because the torque drops. But if the above scenario is
correct, using the commutator as a switch, it will wear out fast. I
wonder how long it will take before he has spent 800 bucks on a bunch
of 25 dollar solutions.
ERS