One of the key features of elevators is the need to be very fast, accurate and smooth with braking systems. This kind of braking with very high reliability is achieved by using Dynamic Braking Resistors (DBR).
Elevators support one only dimensional movement(up or down) and may carry empty load to full capacity.
Stopping an elevator is a two-step operation. The first step is to use regenerative braking to reduce the speed of the elevator. The second step is to use a separate electro-mechanical brake to stop the elevator. While decelerating, elevators allow the full load current to pass through the DBR, which dissipates the power as heat. The resistance value and the heat sink mechanism of the DBR are critical in smooth operation of the elevator.
Cranes provide three-dimensional movement. The variable frequency drive motor of cranes run in two modes – regenerative mode when lowering a load and motoring mode when lifting a load. Just as in the functioning of the elevator, DBRs play a similar role in dissipating the power as heat to allow for rapid and smooth braking.
Dynamic braking reduces the wear-and-tear of the mechanical components due to rapid braking, when compared with friction braking mechanisms especially when heavy loads are involved.
Dynamic Braking Resistors (DBR) from KWK come with varied resistance, power and current ratings. KWK Resistors also require very little service and maintenance. These heavy-duty resistors are designed to be rugged so as to withstand heavy loads and frequent start-stop cycles.