Home Forums General Discussion Technical Questions braking units for ac drives

I'd put in a suitable contactor, that only picks when the brake is picked. Just parallel up the coils...

The normally open contacts would pass the DC bus voltage to the braking units. (or you could interrupt the flow between the braking unit and braking resistor network)

That would keep the braking units from bleeding off excess DC bus voltage inside the VVVF drive, unless the lift is running.

But you better send a sketch to MCE, and get them to bless it, because of the UL rating. They have sent me amended dwgs before, for my changes. You don't wanna incur any liability on yourself or company.

Can you also adjust the MAX INPUT VOLTS parameter in the drive, to shutdown the elevator, if the incomming 3 phase is too high? Who knows, maybe the buildings' generator is giving you a really high voltage, because they might set it for full building load, but with no load on the building, it migh tbe really high..Hell, IDK, just wondering..