Mitsubishi FR - S500 Operating Instructions, Cable thickness and wiring distance, Operation

(8) Cable thickness and wiring distance

If the inverter-to-motor wiring distance is long, the motor torque will decrease

due to a voltage drop in the main circuit cables especially at low frequency output. Use thick cables for wiring to make a voltage drop less than 2%. (A selection example for the wiring distance of 20m (65.62feet) is given on page 11.)

For remote operation using analog signals, the control cable between operator box or operator signal and inverter should be less than 30m (98.43feet) and wire the cable away from the power circuit to avoid induction from other equipment.

When using the external potentiometer to set the frequency, use a shielded or twisted cable, and do not earth the shield, but connect it to terminal 5 as shown below.

(3) 10

(2) 2

(1)

Frequency Twisted 5

setting cable potentiometer

(3)Shielded cable

(2)

(1) Frequency setting

potentiometer

10

2 5

Grounding

When the inverter is run in the low acoustic noise mode, high-speed switching will generate more leakage currents than in the non-low acoustic noise mode. Always ground the inverter and motor. In addition, always use the ground terminal of the inverter to ground the inverter.

5.3 Operating Instructions

(1) Operation

When a magnetic contactor (MC) is provided on the primary side, do not use this MC to make frequent starts/stops. Doing so can cause the inverter to fail.

When an alarm occurs in the inverter, the protective function is activated to stop the output. However, at this time, the motor cannot be brought to a sudden stop. Hence, provide a mechanical stopping/holding mechanism for the machine/equipment which requires an emergency stop.

Since the capacitor needs time to discharge, do not start inspection immediately after powering off the inverter. More than 10 minutes after power- off, make sure that there are no residual voltages with a multimeter etc. before stating inspection.

(2)Wiring

Application of power to the output terminals (U, V, W) of the inverter will

damage the inverter circuit. Hence, before power-on, fully check the wiring and sequence for incorrect wiring and so on.

Terminals P<+> and P1 are designed to connect a dedicated option. Do not connect any equipment other than the dedicated option. In addition, do not short the frequency setting power supply terminal 10 and common terminal 5, and terminals PC-SD.

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