Maintenance Work; Tools; Measurements With The "Old" Equipment Still Working - ABB DCS800 Installation And Start-Up Manual

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Maintenance work

All maintenance must be carried out by a competent electrician, who shall also
have custody of keys to the doors, unless the system is located in switch gear.
All points within this chapter must be observed before any work is begun.

Tools

In addition to the tools needed to maintain electrical parts some special tools are
recommended:
-
Oscilloscope either with galvanically isolating transformer or isolating amplifier
for safe measurements
-
Clamp on current probe; an AC type is sufficient for gate firing pulse measure-
ments; in case the scaling of the DC load current needs to be checked, a DC
type is needed
-
Voltmeter
Make sure, all equipment in use is suitable for that voltage level applied to the
power part!
General hint
In addition to the work specific for the installation of the pure rebuild kit hardware
attention should be paid to features related to drives in general. There is the engi-
neering and the interface to other components in general, the selection of control
cables and their routing, earthing and grounding, screening and other points which
need further considerations. The manual Technical Guide gives some help within
the chapter EMC Compliant Installation and Configuration for a Power Drive Sys-
tem. This chapter gives information specific to fulfill the needs necessary for the
CE marking. Most often CE marking is not the most important target for a system
upgraded by a rebuild kit. Nevertheless using some of the ideas will make the
complete system safer.

Measurements with the "old" equipment still working

Some measurements should be carried out before the existing installation is
switched off and dismantled. They serve to document the existing performance
and get the definition of some signals or terminals of the existing hardware:
- record the actual signals of
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Start-up
the speed
the armature and the field current
line, armature and field voltage
other application related signals
record line and armature voltage to determine the name of the single line
phase and the position of the + and – terminal; this will be an alternative to
disassemble the thyristor stack to check the orientation of the thyristors
at power parts with more than one thyristor in parallel, record the firing
pulse and the thyristor current of each thyristor to be sure, all of them are
conducting
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