LNS Alpha ST320 S2 - Page 36

4-12 CHAPITRE 4: ELECTRICS
ALPHA ST320 S2
3.2. Hydraulic pump power loop
The hydraulic pump M2 is powered by 3 phases 220V AC through KM1 contactor and protected by QM1
breaker.
3.2.1. Circuit breaker - QM1
QM1 interrupts the 3 phases which power the hydraulic
motor as well as emergency stop circuit. If the motor
requires excessive power (the breaking current is set to
2.5 amperes). The circuit breaker activates and button E
trips. Both power supply to hydraulic pump and the
emergency stop loop are interrupted.
After the problem is fixed, reset the circuit breaker by
pressing button E.
3.2.2. KM1
T
he KM1 contactor is energized by 24V DC from PLC
output Y14. When this signal is OFF, the KM1 is de-
energized and the power to hydraulic pump is cut off.
Designation Description
A Power poles input
B Auxiliary contacts
C Rating adjustment (preset at 2.5A)
D Stop button
E Start button
F
Power poles output (connected to
K1)
Designation Description
A Power poles input (from QM1)
B Control circuit
C Status indicator
D Power poles output (to M2)
A
B
C
D
F
E
A
B
C
D