8
Technical amendments reserved, errors excepted
a) Shaft height 56 to 132 (closed bearings)
If the time from delivery to commissioning of the en-
gines is
» under proper conditions (storage in dry, dust-free
and vibration-free rooms) more than 4 years
» more than 2 years under unfavourable conditions
the bearings must be replaced.
b) Shaft height 160 to 355
If the time from delivery to commissioning of the en-
gines is
» under proper conditions (storage in dry, dust-free
and vibration-free rooms) more than 4 years
» more than 2 years under unfavourable conditions
the bearings must be relubricated.
Only identical or compatible greases may be used for
relubrication!
»
Insulation resistance
The insulation resistance of the windings to ground
must be measured before commissioning of the mo-
tors. If the minimum values specified by the manufac-
turer are not observed, the motor windings must be
dried.
The following conditions apply to the measurement:
The insulation resistance of the winding is measured
with a DC voltage of 500V to ground. Here, the measu-
ring voltage is applied until the reading values main-
tain stable. The specified minimum values must be
reached during the measurement:
Minimum insulation resistance for new, cleaned or
repaired windings (at 25°C) 10 MOhm
Critical specific insulation resistance after long opera-
tion time at 25ºC winding temperature 0,5 MOhm/kV
The critical value of the insulation resistance is calcu-
lated by multiplying the nominal voltage (in kV) by the
given specific critical insulation resistance (0.5 MOhm
/ kV).
Example:
critical insulation resistance for =690V:
0,69 kV x 0,5 MOhm/kV = 0,345 MOhm
