Installing a Magnetic Contactor If the power supply for the main circuit gets shut off during a sequence, a magnetic contactor can be used to stop the MxC. When a magnetic contactor is installed on the primary side of the main circuit to forcibly stop the MxC, regenerative braking does not work and the MxC will simply coast freely until it stops. • The MxC can be started and stopped by opening and closing the magnetic contactor on the primary side. Frequently opening and closing the magnetic contactor, however, may cause the MxC to malfunction. The MxC should not be started and stopped more than once every 30 minutes.
• The unit cannot be restarted automatically following an interruption in the power supply when using the digital operator to control the MxC. Connecting Input Power Supply to the Terminal Block An input power supply can be connected to terminals R, S, or T on the terminal block. The phase sequence of the input power supply is irrelevant to the phase sequence created by the MxC. Installing a Surge Absorber Always use a surge absorber or diode for inductive loads near the MxC. Examples of inductive loads include magnetic contactors, electromagnetic relays, solenoid valves, solenoids, and magnetic brakes.
Installing a Noise Filter on Power Supply Side Install a noise filter to eliminate noise transmitted between the power line and the MxC. • Correct Noise Filter Installation Power supply MCCB IM MCCB Other controllers Use a special-purpose noise filter for MxCs. Fig 2.8 Correct Installation of a Power Supply Noise Filter • Incorrect Noise Filter Installation Power supply MCCB MxC IM MCCB Other controllers Power supply MCCB IM MCCB Other controllers Do not use general-purpose noise filters. No general- purpose noise filter can effectively suppress noise generated from the MxC.
Fig 2.9 Incorrect Installation of a Power Supply Noise Filter 2- 11 Noise filter MxC General- purpose noise filter General- MxC purpose noise filter