Dynamic Braking Selection using Inverter Drives SMD (Submicro) and Inverter Drives SMV

Dynamic braking is used when an overhauling load causes regeneration from the motor to occur, especially in situations where the required deceleration time to stop the motor cannot be achieved due to High Voltage nuisance tripping. Most Lenze-AC Tech DB circuits are rated for light-duty use only. The dynamic braking (DB) control circuit is connected to and monitors the fixed DC bus line. When the DC bus reaches 114% of the maximum tolerance, it triggers the chopper circuit in the dynamic brake. The DB circuit will be active whenever the voltage rises on the DC bus. This can occur while the drive is running, while it accelerates or decelerates or even when it is stopped. Using dynamic braking allows a faster deceleration time of a high inertia load. However, fast deceleration of a high inertia load may sometimes cause regeneration and trip the drive into a High Voltage fault. To avoid this, a dynamic brake chopping circuit is switched on when the voltage levels exceed the rated tolerance and brake resistors dissipate the regenerated voltage as excess energy.