Re: Energy dump (was: G201 modifications/update)

Hi,

That is the simplest and most effective solution if the power supply
voltage is at least 15% below a drive's rated voltage. The you can
pick a zener at or just below the drive's rated voltage and
everything will work fine.

This method falls apart with power supply voltages at or near
maximum, especially when unregulated supplies are used.

The supply voltage tracks the primary AC voltage. The AC voltage has
a +/- 15% tolerance. This means if the power company is feeling
particularly frisky, a nominal 80VDC supply might reach 92VDC (80V
times 1.15).

If an 82V zener had been used, you would have a glowing slag of
silicon.

Mariss

--- In CAD_CAM_EDM_DRO@egroups.com, "Henrik Olsson" <henrik-
olsson@t...> wrote:

> Hello list!
>
> Though Mariss 'energy dump circuit' is quite simple it got me

thinking. Wy not just use a zenerdiode with a Vz just under the
drives maximum supply voltage and resistor in series to ground?

>
> I realise that it might have to be a highpower zener (and resistor)

depending on the current that is returned from the motor(s).

> How high is that current anyway? About the same as the motors

current rating or..?

>
> /Henrik Olsson.