Gardner Denver L23, Original Operating And Service Manual

Page: 50 / 64

10 Service and Maintenance
48
10.9 Connection terminals in the switch
cabinet/control transformer settings
DANGER
High voltage – Hazard of shock, burns, or
death
•
Only qualified electricians may work on
the control cabinet.
•
Only perform checks and carry out work
on the screw compressor when the unit
is out of operation, depressurized, and
secured from being switched on again!
•
Push the STOP button on the control
panel. After the soft-stop tiime (30 sec.),
set the on-site main switch to “0”(OFF)
and secure it against being switched on.
DANGER
There is a risk of electric shock from
charged capacitors!
•
Disconnect the system from the mains
and wait 10 minutes before touching
electrical components. The power
capacitors need this time to discharge.
NOTICE
Making incorrect settings to the control
transformer poses a risk to the trouble-free
operating of the system.
Checking the setting of the control transformer
is part of commissioning and part of regular
inspection/maintenance because the supply
voltage can change.
The connecting terminals in the switch cabinet have to
be checked and, if required, re-tightened during first
commissioning and afterward according to the
maintenance schedule.
Fig. 27
Check the control transformer setting as
follows:
•
Switch the unit on as described in Chapter 8.3.
•
Check the control transformer output voltages while
operating under load. Several tapping points are
provided for this purpose (see circuit diagram).
•
Switch the unit off as described in Chapter 8.5.
Change the control transformer setting as
follows, if the output voltage is not correct:
•
Change the control transformer setting accordingly.
•
Set the on-site main switch to “0”(OFF) and secure it
against being switched on.
•
L23RS-L29RS: wait 10 minutes before touching
electrical components. The power capacitors need
this time to discharge.
•
Change the control transformer setting. Fig. 27
illustrates an example.
•
Then, check the setting again.