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28 Electrical installation
+F290) of the unit. Open the disconnecting device of the energy storage
connected to the unit (outside the drive cabinet).
•
Open the auxiliary voltage switch-disconnector (if present), and all other
possible disconnecting devices that isolate the drive from dangerous voltage
sources.
•
In the liquid cooling unit (if present), open the switch-disconnector of the
cooling pumps.
•
If you have a permanent magnet motor connected to the drive, disconnect
the motor from the drive with a safety switch or by other means.
•
Disconnect all dangerous external voltages from the control circuits.
•
After you disconnect power from the drive, always wait 5 minutes to let the
intermediate circuit capacitors discharge before you continue.
3.
Protect any other energized parts in the work location against contact.
4.
Take special precautions when close to bare conductors.
5.
Measure that the installation is de-energized. Use a quality voltage tester. If the
measurement requires removal or disassembly of shrouding or other cabinet
structures, obey the local laws and regulations applicable to live working (including
– but not limited to – electric shock and arc protection).
•
Before and after you measure the installation, verify the operation of the
voltage tester on a known voltage source.
•
Make sure that the voltage between the drive input power terminals (L1, L2,
L3) and the grounding (PE) busbar is zero.
•
Make sure that the voltage between the drive output terminals (T1/U, T2/V,
T3/W) and the grounding (PE) busbar is zero.
Important! Repeat the measurement also with the DC voltage setting of the
tester. Measure between each phase and ground. There is a risk of dangerous
DC voltage charging due to leakage capacitances of the motor circuit. This
voltage can remain charged for a long time after the drive power-off. The
measurement discharges the voltage.
•
Make sure that the voltage between the drive DC terminals (UDC+ and UDC-)
and the grounding (PE) terminal is zero. In cabinet-built drives, measure
between the drive DC busbars (+ and -) and the grounding (PE) busbar.
WARNING!
The busbars inside the cabinet of liquid-cooled drives are partially coated.
Measurements made through the coating are potentially unreliable, so only
measure at uncoated portions. Note that the coating does not constitute
a safe or touch-proof insulation.
6.
Install temporary grounding as required by the local regulations.
7.
Ask for a permit to work from the person in control of the electrical installation
work.
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