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Isolation from AC supply networks
1. Clearly identify the work location.
2. Disconnect all possible voltage sources.
•
Open the main switch-disconnector [Q1], or rack out the main breaker [Q1] of the
drive (whichever is present). Note that some drives have two switch-disconnectors
or main breakers [Q1.1 and Q1.2].
•
Open the disconnector of the supply transformer as the main disconnecting device
of the drive does not remove the voltage from the input busbars of the drive or from
the voltmeter (option +G334), or BAMU auxiliary measurement unit, auxiliary control
voltage switch [Q21], charging circuit disconnector [Q4] or others.
•
Make sure that reconnection is not possible. Lock the disconnectors to open position
and attach a warning notice to them.
•
Disconnect any external power sources from the control circuits before you do work
on the control cables.
•
After you disconnect the drive, always wait for 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 multimeter with an impedance of at least 1 Mohm.
•
Make sure that the voltage between the drive input power terminals and the
grounding (PE) busbar is close to 0 V.
6. Install temporary grounding as required by the local regulations. Close the grounding
switch (option +F259, [Q9]) if present, or connect the AC and DC busbars to PE with a
temporary grounding tool.
7. Ask for a permit to work from the person in control of the electrical installation work.
Electrical installation 37
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