Configuration of control circuit:
To switch the motor from inverter operation to commercial-power operation or vice versa the inverter ISW50 function will be
used.
1. DIGITAL INPUTS (in this case FWD, X1 and are used)
- FWD: digital input set as FWD function (RUN command).
- X1: digital input set as mutispeed SS1 function (speed).
- X2: digital input set as ISW50 function (to switch the motor).
2. DIGITAL OUTPUTS (in this case Y1, Y2 and Y3 are used)
- Y1: digital output set as SW52-1 function (this digital output will be connected to relay 1. Relay 1 will open or close
the primary contactor SW52-1).
- Y2: digital output set as SW52-2 function (this digital output will be connected to relay 2. Relay 2 will open or close
the secondary contactor SW52-2).
- Y3: digital output set as SW88 function (this digital output will be connected to relay 3. Relay 3 will open or close
the commercial power contactor SW88).
RUN command
(FWD)
Speed
ISW50
To switch the motor
Switching...:
1. INVERTER OPERATION ------> COMMERCIAL POWER OPERATION
If the digital input set as ISW50 function is changed from ON to OFF.....
(1) The inverter output is shut off immediately (IGBT off).
(2) The inverter primary contactor (SW52-1) and the inverter secondary contactor (SW52-2) are opened immediately.
(3) If the RUN command is kept during t1 time (H13 + 0.2 seconds), the commercial power contactor SW88 is closed
and the motor is switched to commercial power operation.
2. COMMERCIAL POWER OPERATION ------> INVERTER OPERATION
If the digital input set as ISW50 function is changed from OFF to ON.....
(1) The primary contactor SW52-1 is closed immediately giving voltage to the inverter (inverter is powered).
(2) The commercial power contactor SW88 is opened immediately (desconnecting the motor from the line).
(3) After t2 time (time required for the inverter main circuit to get ready + 0.2 seg) the inverter secondary contactor
SW52-2 is immediately closed.
(4) After t3 time (H13 + 0.2 seg), the inverter starts driving and the motor is inverter controlled up to the desired
frequency.
PLC
FWD
X1
SOURCE
X2
CMY
CM
Chapter 6: Function codes and application example
Y1
Y2
Y3
Relay 1 (related with
SW52-1 inverter primary
contactor)
Relay 2 (related with SW52-
2 inverter secondary
contactor)
Relay 3 (related with
SW88 commercial power
contactor)
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