Had a bunch of them at a previous job (225D and 240D) do not profess
that I understand how they worked, but do why they were needed in our
application. Large slowly spinning arms with molds attached which were
never truly balanced. Regenerative drives help get back *some* of the
energy used to raise the heavy side as it falls and the light side
Also astounded by the difference in appearance between 20 + year old
drive boards and there modern replacements. Old ones are absolutely
crammed with components, new one look almost bare! Will try to get a
picture the next time I'm down that way...
Oh, posting from rec.crafts.metalworking. Just noticed this is cross
posted to two groups I am not following.
That control does NOT put power back into the grid.
It is a "plugging" brake that reverses the torque on the motor to stop
it. Standard 4 quadrant control. They call it "regenerative" braking,
but in reality it is "dynamic" braking.
True regenerative braking puts power back into the supply.
Dynamic braking uses electromagnetic force to brake, but does not
return the power to the source. DC dynamic braking can also be
regenerative. AC dynamic braking is seldom regenerative. This
particular unit is not. It is described as an AC 4 quadrant controller
for a DC motor - and that is what it is..
In a DC system, 4 quadrant is often, (ok, usually) but not always,
regenerative. Not usually on an AC supply system.
4 quadrant symple means it can controll both accelleration and
decelleration in both directions - hense - 4 quadrant.
Dynamic braking in a 4 quadrant AC control generally sinks
(dissipates) the decelleration power, while regenerative braking in a
4 quadrant DC system generally returns the braking energy to the
Just my experience. 2 quadrant control can also be either regenerative
Please show me a circuit for 4 quadrant control of a DC motor from an
AC supply that implements true regenerative braking. Explain how the
output of the DC motor is syncronized to the ac line frequency. Then
give me the name and manufacturer of the contoller, with specs on the
amount of current it is capable of returning to the grid, and I'll
I am fully aware of DC regenerative 2 and 4 quadrant motor controls,
and I know how an induction motor can be used as a generator, but I'd
really like to know how to recover the power from my DC motor to the
AC grid. (not just recover it into a battery)
"Electro-Majic DC". It couples directly to AC lines with no problems. No
need for syncronous inverters, no voltage control, no nothin'. Just hook
it up and pedal your bike for an instant reduction - and even payback - on
your power bill!
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