by cncdrive » Sat Jan 05, 2019 12:50 am
Well, the issue with high voltage and high power is that when the motor is deccelerating rapidly then it acts as a generator and so it is pumping voltage back to the power supply.
If the voltage rises above the voltage rating of the mosfets in the drive (250Volts) then the mosfets will damage and also the capacitors in the drive and in the PSU can damage.
The braking circuit is to protect against these overvoltage events. It measures the voltage of the PSUand fires if the voltage gets too high, it connects some power resistors on the power supply rails which dissipates the regenerative energy and so they protect the drive and the power supply.
We generally recommend the usage of the braking circuit above 80Volts, because usually those motors which work with that high voltage have high enough power to cause the above mentioned problem.
However it is very hard to make a caulculation on it, because if it is needed depends on many factors... but a braking circuit is not that expensive and if it is installed then the system will be safe...