FUNDAMENTALS Service Manual M4 - M10
29.12.1999 Page 16
Even panel of the drive is blank, it doesn’t guarantee, that power is cut off and
the drive is unpowered. Make sure the power is cut off from the line and there
is no by-pass system to cause risk of electric shock.
Wait at least 5 minutes from the moment, that panel blanks after power has
been cut off from the line. After time above cover of the drive can be opened
for final safety checking before further measures with the drive.
Make sure voltage at input terminals does not exist. Measure remaining
voltage in DC bus and make sure level of the voltage is on safe level before
further action.
Use only appropriate devices which are specified for voltages can exist in
circuits.
Measure voltage from output terminals from back feeding by-pass
connections, if exists, disconnect in prior to proceed with analyses.
After drive has been discovered to be unpowered, it is recommended to
disconnect all cables from the drive which can supply dangerous voltages to
the drive, including control wiring. Clear out dangerous voltages entering
from the wiring of process control, before further measures. Remember
always to follow local / national safety rules and regulation.
5.3.2 ESD precautions
Electrostatic discharge (ESD) may destroy electronic components based on
MOS- or comparable technology. IGBT is voltage controlled component and is
sensitive for excessive voltages cross gate-emitter, and gate collector
junctions. Component boards are relatively complicate circuits including
hundreds...thousands of ESD sensitive components. For this reason, always
respect ESD warnings and decals and do anything to avoid causing damages
by the careless handling of component boards and other components. In any
cases, consider component to be as ESD sensitive if you don’t know, is the
particular part sensitive or not.
Working area must be ESD safe area. Thus all electrostatic materials are
removed and working level is covered with conductive materials. ESD wrist
wrap should be weared properly, if circuitries are intended to be touched. ESD
safe shoes should be weared regularly in rooms, where repairs are
performed.
The ESD protection and handling of the ESD sensitive components should be
follow the standard EN100015-1, the committee draft IEC 101/18/CDV and the
committee draft IEC 101/19/CDV.
To Next Page
Loading...
Need help?
General
