At 10:25 AM 8/23/2004, Roberts II, Charles K. wrote:

>The Brake is engaged when no voltage is applied, the break is disengaged
>when there is a voltage. When I took it apart it looked as if it used a
>spring to hold the brake shoe onto the shaft and a solenoid to release
>it.
>That's all I got, there is not much information on the manufactures
>site.

The diode has to have enough PRV to withstand the on-state.
Then the energy stored in the inductor needs to dump through it's own resistance, so that defines the maximum one-shot energy the diode needs to sustain.
You don't often see the math for this presented, I suppose it's because generally speaking, a 1N400X diode will handle most loads.

I've tried to get this sort of info out of stepper chip makers.
They say they have on-chip diodes, but when you press for details, they are often unable to tell you how much the diodes can handle.

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