Hi guys,
Since I'm the one who originally designed and published the circuit that Irfan has attached to the first message in this post I thought I'd explain a bit why I did it the way I did....

Before designing the circuit I looked at both of Mariss' circuits that he attached to his post (they've both been available on Geckodrive's Yahoo-group for quite some time).

Dump1 was discarded because I couldn't source a PNP transistor rated at 150-170V and ~30A. Dump2 was also discarded because I'm using a three-phase rectifier and I honestly couldn't figure out if that circuit would work with a three phase rectifier. (I confess, I'm embaressed). I did post a question on the Geckodrive Yahoogroup about it but it was/is unanswered so I set out to design my own.

Also, on the schematic you see two connections marked Bleeder+ and Bleeder-. In my own system these are connected to a 7.5ohm resistor via the normally closed contacts of the main contactor. When entering E-stop the contactor deactivates and connects the resistor across the powersupply capacitors, discharges them and "breaks" the motors. Agreed, it requires a second resistor....


Mariss, I'm a bit confused that you say a revese energy dump isn't needed under normal conditions. When testing my system I set the dump-circuit to activate at 15V above nominal powersupply voltage (nominal is 130VDC) and it clearly activates during decceleration from high speed. There's even a video on Youtube (not mine but he's using "my" dump circuit) where you can see the difference with and without the circuit. I'll see if I can find it but I think I must have misunderstood you or something.

/Henrik.