ABB UNO-DM-2.0-TL-PLUS Manual page 161

When the device has just been switched off, it may have hot parts as a result of overheating
of the heated surfaces (e.g.: transformers, accumulators, coils, etc.) so be careful where you
touch.
Some inverter parts may be subject to voltages that could be hazardous for the operator.
Before performing any work on the inverter, follow this procedure for safely isolate the inverter.
1. Preliminary checks
• Weather conditions: In the risk assessment prior the intervention it
is of paramount importance to evaluate the weather conditions. This
procedure can be applied only in case of dry environment. Don't
proceed in case of rain (even light) or high humidity.
• PPE Check: Verify the integrity of the PPE that is going to be used
to perform the operations.
• Equipment check:
Check the voltage tester is working correctly:
- Perform an integrity check of the instrument in general; examine
the test terminals, its integrity and make sure they are properly fixed;
make sure the batteries level is enough high (don't use the instrument
in case the message "LOW BATTERY" is present) or replace them.
- Perform test of the instrument using an energized AC socket and a
DC voltage source (example: battery in the service car) with known
voltage level; in case the instrument is provided with a self-test
feature, follow the instructions provided in the instrument manual to
carry out the self-test.
Check the DC current probe is working correctly:
Check the DC current probe is properly working, make sure to perform
the "ZERO-OFFSET" procedure and to select DC measurement
range.
2. Wear the appropriate PPE for carrying out the operations (arc-
flash rated wearing, dielectric helmet with visor, Arc-flash
rated head protection (balaclava), insulating gloves). All the
following activities (till the completion of the procedure) must
be performed wearing the PPE.
3. Check the absence of dangerous voltages on inverter enclosure
respect to ground:
• Using a voltage detector, check the absence of dangerous voltage
on the inverter chassis. The measurement points are between the
inverter chassis (it shall be selected a non-painted point, like one
of the screws of the front panel) and a ground point outside the
inverter.
- 161 -
8 - Maintenance