7.4.WIRING DIAGRAM
The operating diagram of the electrical system consists of a main power circuit and a low voltage auxiliary control circuit
consisting basically of:
MP):
Electrohydraulic control unit motor, 1.5 kW - 4
poles.
FR1):
Magneto-thermal
mushroom-shaped release and reset button.
EV1):
Pneumatic solenoid valve for fall-proof safety
hook release control.
EV2):
Hydraulic solenoid valve for lift descent control.
KP):
Three-pole contactor + 24 V pump motor
auxiliary
TM):
50 VA transformer, 400-230/ 24 Volt.
PS):
<Ascent> button.
PD):
<Descent> button.
SQ2):
Pull bar coupling safety pressure-switch.
SQ1):
Descent mode control safety limit-switch.
PDA):
High descent button.
PDB):
Low descent button.
LED1):
Power-on> LED.
LED2):
Ascent LED.
LED3):
Descent LED.
LED4):
Release LED.
F1-F2):
3.15A 5x20
transformer
protection fuse.
F3-F4):
1A 6.3 x 31 transformer primary circuit protection
fuse.
overload
cutout
with
secondary
circuit
OPERATION:
When the contacts of the master switch (FR1) are closed,
the current fl ows in both circuits.The transformer (TM),
connected to two phases of the power circuit by means of
the two-pole fuse-carrier (F3-F4), lowers the voltage from
400/230 V to 24 V in order to feed the auxiliary circuit. In
this way, only the control unit motor power supply circuit
is powered by the 400/230 V line voltage.The pump is
rotated by the electric motor when the contacts of the
contactor (KP) are closed by the closing of the contacts of
the <ascent> (PS) or <descent> (PD) buttons.
The closing of the <ascent> button contacts simultaneously
triggers the energising of the <ascent> solenoid (EV1) of
the hydraulic solenoid valve.The closing of the <descent>
button contacts simultaneously triggers the energising of
the <ascent> solenoid (EV2) of the hydraulic solenoid
valve and the solenoid (EV1) of the pneumatic solenoid
valve for fall-proof safety hook release.
The auxiliary control circuit is disabled when the contacts
of the mushroomshaped emergency button (FR1) are
opened by the operator, preventing all movement.
This also disconnects all voltage from both the auxiliary
circuit and the power supply to control unit motor (MP). In
order to resume normal operation, the mushroom-shaped
emergency button must be released and the magneto-
thermal overload cutout (FR1) must be reset.
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