This is essential for safety since the inverter module may not be able to break the currentif the chopper remains conductive in a fault situation. An example wiring diagram is shownbelow. ABB resistors are equipped with a thermal switch (1) inside the resistor assemblyas standard. The switch indicates overtemperature and overload.We recommend that you also wire the thermal switch to a digital input of the inverter module.L1 L2 L312345613143412K1ΘOFFONL1 L2 L3110 +24Vx DIx23Thermal switch1.Drive system2.ACS880-1043.￭ Protecting the resistor cable against short circuitThe DC fuses of the inverter module will also protect the resistor cable if the cable is identicalwith the inverter input cable.Mechanical installationAll brake resistors must be installed outside the drive. Follow the resistor manufacturer’sinstructions.Electrical installation￭ Checking the insulation of the brake resistor assemblyCheck the insulation of each brake resistor assembly as follows:1. Check that the resistor cable is connected to the resistor, and disconnected from theinverter module terminals R+ and R-.2. At the inverter end, connect the R+ and R- conductors of the resistor cable together.Measure the insulation resistance between the combined conductors and the ProtectiveEarth (PE) conductor by using a measuring voltage of 1000 V DC. The insulationresistance must be higher than 1 Mohm.332 Resistor braking using frames R1i…R4i inverter modules
