Operating instructions
69
Tunnel/connection box
Control box
Compressor power connections
Example of the internal safety system
For these checks the circuit breaker/disconnect switch of
the VFD control box must be in the open position.
ATTENTION: Isolation using the main disconnect switch
does not disconnect the voltage to the power conductor
connection terminals in the power supply to the machine.
Check the electrical connections: tightening torques and
connector tightening on the electronic boards.
Checking the starter in the installation:
• The nominal current and capacity data for the starter
must be in accordance with the data calculated for the
machine in the application. If the starter is installed in
a delta branch of the motor (square root of three
installation), verification is done by a comparison with
the operating current of the starter multiplied by √3.
• Check that the voltage at the power connection
terminals of the machine complies with that on the
component name plates.
18.2.1 - Energising the PIC control circuits and the crankcase
heater
The circuit breaker/disconnect switch QF101 and disconnect
switch QF1 must be closed to carry out the following checks
on these circuits. The checks are the same as those for the
standard machine.
On the CCM board:
• Remote set point reset (4-20 mA), J5-3/4 CCM
• Demand limiter, J5-1/2 CCM
On the ISM board:
• Alarm report, J9-16/15
• Machine power consumption, J8-1/2
• Ice storage contact, J2-3/4
• Safety shut-down, J2-1/2
• Chilled-water temperature reset, J5-3/4
• Evaporator hydronic pump control (obligatory),
J9-7/8
• Condenser hydronic pump control. J9-9/10
On the terminal strip:
• Remote start/stop button, 31/32
• Operation report, 130/131
• High-pressure control valve control and supply, 1A/1B;
1C/1D
• Remote control, 31/32
17.6.1 - Isolation
SAFETY CONSIDERATION REMINDER: Disconnect
the power supply before working on the control box.
The circuit breaker/main disconnect switch allows isolation
of the complete electrical equipment from its power supply
with the exception of the power conductor connection
terminals for the installation.
IMPORTANT: Disconnecting the power equipment using
the handle of disconnect switch QF101 also disconnects
the control equipment and power supply to the oil pump.
To prevent compressor lubrication problems, do not switch
off the machine using the disconnect switch, if the compres-
sor is still energised.
17.6.2 - “Square root of three” installation and access to
the motor terminals
In 400 V applications the starter is normally installed in a
delta branch of the compressor power supply circuit. This
configuration allows reducing the value of the current that
passes through the starter by a factor of √3.
With this type of wiring, if the power supply is not discon-
nected and the motor is de-energised, there is always voltage
present at the electrical motor terminals.
To warn and prevent people from working on the unit, a
locking system with a captive key is used to access the
motor terminals.
Access to the compressor terminals:
The control box element between the main control box and
the compressor is locked by a key. The key becomes captive
in the door, when this is open. Once the door is closed
again, the key must be put back in its place on the door
with the handle to operate the main machine switch. The
control box door cannot be closed and the disconnect
switch is again locked when the key has been put back in
its place.