Operation On A Converter With A Low Pulse Frequency; Measuring The Insulation Resistance Before Commissioning - Siemens SIMOTICS FD 1LL1 Operating Instructions Manual

● Any supplementary motor monitoring devices and equipment have been correctly
● In continuous operation, the motor cannot exceed the specified upper speed limit n
7.2.1

Operation on a converter with a low pulse frequency

NOTICE
Increased motor temperature
If the pulse frequency is less than the rated pulse frequency, then increased motor losses
occur. This results in a higher motor temperature.
● Reduce the power to prevent exceeding the temperature class and to avoid consequential
● Contact the Service Center if necessary.
Dangerous voltage via the converter
As long as the feeding converter is switched on, or the DC link of the converter is not
discharged, there can be a voltage at the motor terminals even when the rotor is not moving.
The voltage is up to 1000 V, depending on the converter type.
Ensure that the five safety rules (Page 15) are followed before working on the motor.
7.3

Measuring the insulation resistance before commissioning

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?
SIMOTICS FD 1LL1
Operating Instructions 01/2019
connected and are functioning correctly.
undershoot the lower speed limit n
The permissible acceleration time to the limit speed n
assignment.
premature thermal aging of the insulation.
WARNING
7.3 Measuring the insulation resistance before commissioning
.
min
depends on the parameter
min
Start-up
or
max
93