Hoyer HMA2, Manual

Page: 8 / 40

8
Motor
Manual
ured insulation resistance is less than 10 M
Ω
at 25°C, the
winding must be oven dried . The nominal value is typically
100 M
Ω . If the measured value is less than 2 M Ω , the insu-
lation resistance is not acceptable . When oven drying the
windings, set the oven temperature to approximately 85°C
for 10 to 18 hours, followed by 100°C for 7 to 9 hours . The
nominal insulation resistance drops by 50% for every 20°C
rise in motor temperature . Measuring equipment must al-
ways be calibrated at least every year . Note that drain plugs
or valves must be open during heating . After heating, make
sure the plugs are fitted again .