User Manual EM303B General Purpose Inverter Figure 3-4 Standard Wiring of Main Circuit 3.2.5 Wiring Main Circuit on Input Side Installing a Circuit Breaker Always install an air circuit breaker (MCCB) between the power supply and input terminals. Choose a MCCB with a capacity of 1.5-2 times of the inverter’s rated current. The time characteristics of MCCB should meet that of inverter’s overheating protection (150% of rated current /1 minute). If single MCCB is shared by two or more inverters or other devices, the contact of fault output relay shall be connected to power contactor coil, so that the power supply will be turned off by the fault signals, as shown in Figure 3-5.
Figure 3-5 Connecting to Input Circuit Breaker Installing a Leakage Circuit Breaker High frequency leakage current is generated by high frequency PWM signal output of inverter. Select a special purpose leakage breaker with a trigger current≥30mA. For a regular leakage breaker, the trigger current≥200mA and the active time at 0.1S or above. Installing an Electromagnetic Contactor Install an electromagnetic contactor which is applicable to inverter as shown in Figure 3-5. 26 EM303B-0R7~015 Braking Resistor (Optional) PB R U S V M T W EM303B-018~400 Braking Resistor(Optional) Braking Unit(Optional) R U S V M T W MCCB MC OFF ON MC EM303B R S T EBFault Relay Contact EC MC