User’s Guide for EM760 series high-performance vector inverter Chapter 8 Select Accessories 8.1 Braking Resistor When the braking performance does not meet the customer requirement, it is required to connect an external braking unit and braking resistor to realize timely release of energy. 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 EM760 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. The wires listed above refer to the outgoing wires of a single resistor. If resistors are connected in parallel, the bus should be enlarged accordingly. The withstand voltage of the wires should be AC300V or above for the single-phase model and AC450V or above for the three-phase model. Cables should be resistant to 105℃.
8.2 Braking unit EM760 inverters of 22kW or above and without built-in braking units need to be optionally equipped with our BR100 braking units (power range: 45-315kW). The models of our braking units are as follows.
48 Motor Resistance Resistor Power Wire (mm2) Connected Inverter Model (kW) (Ω) (W) to Resistor EM760-0R7G/1R5P-3B 0.75/1.5 ≥360 ≥200 1 EM760-1R5G/2R2P-3B 1.5/2.2 ≥180 ≥400 1.5 EM760-2R2R/3R0P-3B 2.2/3.0 ≥180 ≥400 1.5 EM760-4R0G/5R5P-3B 4/5.5 ≥90 ≥800 2.5 EM760-5R5G/7R5P-3B 5.5/7.5 ≥60 ≥1000 4 EM760-7R5G/9R0P-3B 7.5/9.0 ≥60 ≥1000 4 EM760-011G/015P-3B 11/15 ≥30 ≥2000 6 EM760-015G/018P-3B 15/18 ≥30 ≥2000 6 EM760-018G/022P-3B 18.5/22 ≥30 ≥2000 6 EM760-022G/030P-3B 22/30 ≥15 ≥4000 6 EM760-030G/037P-3B 30/37 ≥15 ≥4000 6 EM760-037G/045P-3B 37/45 ≥10 ≥6000 6 EM760-045G/055P-3B 45/55 ≥10 ≥6000 6 EM760-055G/075P-3B 55/75 ≥7.5 ≥8000 6 EM760-075G/090P-3B 75/90 ≥6 ≥8000 6 Minimum Model and Average Braking Peak Current Applicable Inverter Application Resistance specification Current Iav(A) Imax(A) Power (kW) (Ω) BR100-045 Energy 10 45 75 18.5~45