Chapter 5 Main Circuit Terminals MS300 5-2 Tighten the screws in the main circuit terminal to prevent sparks caused by screws loosened due to vibration. If necessary, use an inductive filter only at the motor output terminals U/T1, V/T2, W/T3 of the AC motor drive. DO NOT use phase-compensation capacitors or L-C (Inductance-Capacitance) or R-C (Resistance-Capacitance), unless approved by Delta. DO NOT connect phase-compensation capacitors or surge absorbers at the output terminals of AC motor drives. DO NOT connect brake resistors directly to +1/DC+ to DC-, +2/B1 to DC- to prevent damage to the drive or to the brake resistors.
Ensure proper insulation of the main circuit wiring in accordance with the relevant safety regulations. Main input power terminals R/L1, S/L2 and T/L3 have no phase-sequence requirement; they can be connected in any sequence. Add a magnetic contactor (MC) to the power input wiring to cut off power quickly and reduce malfunctions when the AC motor drive protection function activates. Both ends of the MC should have an R-C surge absorber. Use voltage and current within the specifications in Chapter 09. Refer to Chapter 09 Specifications for details.
Although the leakage current of one single MS300 drive is less than 10 mA, DC electric shock may still occur due to the leakage current from other equipment such as motors and leads. Therefore, it is recommended that you install one of the followings to prevent danger caused by electric shock. 1. Use a copper wire with a cross-section of 10 mm2 or above or an aluminum wire of 16 mm2 as the connection between the casing and the ground. 2. Install an Earth Leakage Circuit Breaker (ELCB). Due to the high frequency current of the leakage current of the AC motor drive, select a Type B ELCB specifically for the drive when using an ELCB.
For tripping or malfunctions on the usage of ELCB, refer to Section 7-8 Capacitive Filter for details. The power system of the AC motor drive affects the power factor, so select a MCCB with larger capacity. Use shielded wire or conduit for the power wiring and ground the two ends of the shielding or conduit. DO NOT run and stop the AC motor drives by turning the power ON and OFF. Run and stop the AC motor drives by sending the RUN and STOP commands through the control terminals or the keypad. If you still need to run and stop the AC motor drives by turning the power ON and OFF, do so no more often than ONCE per hour.
To comply with UL standards, connect the drive to a three-phase three-wire or three-phase four-wire Wye system type of mains power system. Output terminals of the main circuit Use well-insulated motors to prevent any electric leakage from motors. When the AC drive output terminals U/T1, V/T2, and W/T3 are connected to the motor terminals U/T1, V/T2, and W/T3 respectively, the FWD LED indicator on the digital keypad is ON. This means the AC motor drive executes running forward, and the motor rotates counterclockwise (viewed from the shaft end of the motor, as shown in Figure 5-1).