CONTACTORS - AUTOMATION
1. So called “3-wires control” to realize - the base connection for contactors automation; being used the ON and OFF push
buttons, as control elements. The As. motor protections are respected (it’s got enough in the
diagram, only).
L1 L2 L3 N
QM1
0
1
FU1
FA1
KM1
M
FU2
SB0
SB1
FA1
KM1
1KM1
2 Reversing Rotation – 3-phase As. motor to realize the connection for contactors automation – for Reversing Rotation – 3-phase As.
motor. The reversing is realised as the change of the phases sequence (to exchange 2 phases
between themselves). The breaking contacts 2KM1 and 2KM2 are used as blocking – to be
prevented the contemporary switching - the contactors KM1 and KM2.
L1 L2 L3 N
QM1
0
1
KM1
M
KM2
SB0
SB1
KM1
2KM2
1KM1
SB2
2KM1
1KM2
KM2
3. The Y/delta change-over switching - by As. motor Automatic start
To realize the connection for contactors automation - by As. motor Automatic start (using the
Y/delta change-over switch). The contactors KM1 and KM3 realize the star connection; and
the contactors KM1 and KM2 – the delta connection. If, the contemporary switching-on – all
3 contactors – the inlets short connection would be realized, so that this hazard has to be
excluded by the optional contacts using. To be ensured the NO-error operation, it’s necessary
– the breaking contact (contactor KM3) to be disconnected earlier, then the making contact
switch-on (BBM - break before make). The time relay KT1 ensures the disconnecting the
contactor KM3 (after the preset time – what is respecting the supposed time for starting
motor); and KM2 switching. The breaking contact 2KM2 is blocking the KM3 re-connecting.
(For the special starters-sets Y/delta, the mechanical blocking way (the rod) – is used – to be
excluded the contemporary switching-on – the contactors KM2 and KM3, too. To be
prolonged the time between the KM3 switching-off; and the KM2 switching-on – it’s possible
to do it by the other optional relay KA using (in the KM2 position). If, relay KA is ON; then
the power contactor KM2 is switching.
Note: The line-to-line voltage 230V has to be set for the used As. motor.
L1 L2 L3 N
QM1
KM3
KM1
0
1
M
KM2
SB0
SB1
KT1
2KM2
2KT1
KM3
KM1
1KM3
1KM1
KM2
2KM3