I presume it's an direct drive (controlled by on-off switch) motor. Start up acceleration can be expected higher than DC braking deceleration. In so far, the ramp discussion seems to me like a little bit of overengineering. But if you like it...
I still believe that the least effort solution for smooth DC braking is applying a low constant DC voltage (e.g. 10% of rated AC motor voltage) respectively a DC current below rated motor current. That's how a VFD DC brake option usually works. I would try before designing complex solutions. For a short braking time of 2 s, a large power resistor can be used set the current.
I do not have an adjustable power supply, but tried one with fixed output of 50VDC, when applied to that monster motor, it did not brake took few seconds to stop...
The bridge rectifier that delivers the DC fried out. although it was rated 25A/400V. On a 2nd thought, these bridge althu branded are made in China, I doubt the work as rated, and I don t have enough lab to test their actual capacity.
Curiously, basic parameters like motor DC resistance have been never mentioned anywhere in this lengthy thread. I would expect a value below 1 ohm and respectively > 100 A breaking current. Frying the rectifier with it isn't that surprising at all.As the bridge rectifier has a datasheet, worth comparing maximum rated PD to calculated actual PD.
...and as mentioned before, too:as mentioned before, a ucontroller feeds PWM into a dimmer circuit, within 2 seconds ramps output from zero to full. I am almost positive it will work.
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