7.2 Insulation resistance and polarization index
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 41)
7.3 Greasing the roller bearings prior to commissioning
● Regrease the roller bearings prior to commissioning if the machine has been out of
operation for more than a year. The shaft must rotate so that the new grease can be
distributed across the bearings.
● Regrease the roller bearings prior to commissioning in the following circumstances:
– When the machine has been in storage in favorable conditions, e.g. in dry rooms that
are free of dust and vibrations. This applies to the period between delivery and
commissioning, or longer periods of stoppage.
– If the machine has been in storage in unfavorable conditions for more than two years.
Note
Pay attention to the instructions on the lubricant plate.
● If the machine is equipped with grease removal valves, after relubricating, remove the
grease used by completely withdrawing the valve mounted at the bearing several times.
The machine must be operational while doing this.
● If the machine is equipped with grease collection chambers, unscrew the grease collection
chambers after the interval specified on the plate with the motor stationary and remove the
spent bearing grease. If this is not done, the grease will clog and the bearings will overheat.
● Continually check the bearing temperature rise. When using the specified grease quality,
for a maximum room temperature of 40 °C, the maximum bearing temperature rise is 80 K.
Commissioning
7.2 Insulation resistance and polarization index
SIMOTICS HV C 1NB1402-2AA84-4CA0-Z
Operating Instructions 06/2018 71
To Next Page
Loading...
Need help?
General