Measurement Of The Insulation Resistance And Polarization Index In The Context Of Maintenance Work; Inspections In The Event Of Faults; First Inspection After Installation Or Repair; Table 9-1 Checks After Assembly Or Repair - Siemens SIMOTICS TN N-compact 1LH8 Operating Instructions & Installation Instructions

9.1.2 Measurement of the insulation resistance and polarization index in the context of
maintenance work
Measuring the insulation resistance and polarization index (PI) provides information on the
condition of the machine. It is therefore important to check the insulation resistance and the
polarization index at the following times:
● Before starting up a machine for the first time
● After an extended period in storage or downtime
● Within the scope of maintenance work
The following information is provided regarding the state of the winding insulation:
● Is the winding head insulation conductively contaminated?
● Has the winding insulation absorbed moisture?
As such, you can determine whether the machine needs commissioning or any necessary
measures such as cleaning and/or drying the winding:
● Can the machine be put into operation?
● Must the windings be cleaned or dried?
Detailed information on testing and the limit values can be found here:
"Testing the insulation resistance and polarization index" (Page 45)
9.1.3

Inspections in the event of faults

Natural disasters or unusual operating conditions, such as overloading or short circuit, are
faults that overload the machine electrically or mechanically.
Immediately perform an inspection after such faults.
9.1.4

First inspection after installation or repair

Perform the following checks after approximately 500 operating hours or at the latest six
months after commissioning:
Table 9-1
Check
The stated electrical characteristics are being observed.
The permissible bearing temperatures are not exceeded.
The smooth running characteristics and machine running noise have not
deteriorated.
The motor foundation has no cracks and indentations. (*)
(*) You can perform these checks while the motor is running or at a standstill.
SIMOTICS TN Series N-compact 1LH8
Operating Instructions 06/2017
Checks after assembly or repair
Maintenance
9.1 Inspection and maintenance
When the At stand‐
motor is still
running
X
X
X
X X
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