Fan motor starting circuit diagram

The traditional control method of fan power equipment is through manual or relay control, which has problems of poor reliability and flexibility. For example, due
to the large capacity of the motor , there are problems such as long starting time, low starting current, and poor operating safety and reliability. To this end, multiple
measures need to be taken to realize automatic control of high-pressure centrifugal fans and ensure the safe operation of the system. This example discusses the issue of PLC control of high-pressure centrifugal fans
.
    (1) System control requirements In order to solve the above problems, it is necessary to adopt measures such as reducing the starting load when starting the centrifugal fan,
reducing the starting current through the star-delta conversion method, and performing safety interlock control. The fan motor starting main circuit is shown in Figure 26-21.
Among them, when the contactors KM1 and KM2 are connected and KM3 is disconnected, the fan motor coil is star-connected; when the KM2 and KM3 contactors are connected and KM1
is disconnected, the fan motor coil is delta-connected. KM1 and KM3 should be interlocked.
    (2) The PLC selection and I/O definition system is controlled by a coMl type PLC produced by OMROM Company. The I/O
address allocation of PL.C is shown in the table