27
6. Preparations for commissioning
Connecting terminals for heater (option)
For L37S-L75 with 380/400/415 V:
• Connecting terminals for heater
230 V ±10 %
• 2.0 kW, 1P/N/PE
• Integrated thermostat
• Graphical symbol :
with ventilator
• Supply of the unit :
3P/PE
Fig. 13
435V 415V 400V 380V 360V
Option
Serie
Checking the setting of the control-power
transformer
The control-power transformer is factory-preset to the
rated voltage. However, practice has shown that the ac-
tual supply voltage often differs from this value. In order
to adjust the unit to the local conditions, the setting of
the control-power transformer must be checked by
measuring the control-power transformer supply volta-
ge under load and, if required, re-set. Several tapping
points are provided for this purpose (see circuit dia-
gram).
Danger
.
When carrying out adjustment work on the control-
power transformer, the unit must be off circuit.
Work on the control cabinet may only be carried
out by electrotechnical specialist personnel.
Important
A wrong setting of the control-power transformer
jeopardizes the trouble-free operation of compres-
sor units and can result in malfunction or damage.
The verification of the control-power transformer
setting is a must during commissioning and peri-
odic inspection/maintenance, as the voltage supply
conditions may vary.
The correct setting should be checked in on-load
operation of the unit by measuring the control-po-
wer transformer output voltage.
Start-up of the unit after connection to the
electric network/Checking the direction of
rotation
After connection to the electric network the unit can be
started up for the first time. Make sure that the com-
pressed air lines are connected and observe the follo-
wing notes:
Important
When connecting a compressor unit to the electric
network for the first time, it is necessary to check
the drive motor for the correct direction of rotation
(see arrow).
In the case of a wrong direction of rotation stop
the unit immediately by actuating the emergency
OFF push-button. The normal stop push-button
stops the drive only after the soft stop time (several
seconds).
Even a short operation of the drive in the wrong di-
rection of rotation (approx. 2 seconds) results in se-
vere damage or consequential damage.
