User Guide of EM730 Series Inverter Chapter 8 Select accessories 8.1 Braking Resistor If the braking performance does not meet the customer requirements, an external braking resistor is needed to release energy in a timely manner. The power of the braking resistor can be calculated by the following formula: Resistor power Pb = inverter power P Ч braking frequency D D - Braking frequency. This is an estimated value, depending on the load conditions. Under normal circumstances, D is as follows:
D=10% under ordinary loads D=5% for occasional braking loads D = 10% to 15% for elevators D = 5% to 20% for centrifuges D = 10% to 20% for oilfield kowtow machines D = 50% to 60% for unwinding and winding. It should be calculated based on the system design indicators. D = 50% to 60% for lifting equipment with a lowering height over 100m The recommended power and resistance for the braking resistor of the EM730 series inverter are given in the table below. The recommended resistor power is calculated based on the braking rate (10% to 20%). It is for reference only.
If the inverter is used in the case of frequent acceleration/deceleration or continuous braking, the power of the braking resistor needs to be increased. The user can change the value according to the load conditions, but within the specified range. 57