Siemens SIMOTICS GP Operating Instructions Manual page 87

WARNING
Overheating of the roller bearing.
If the roller bearings are not regularly re-greased, local overheating
may be possible, and, as a consequence, an explosion in an explosive
atmosphere. This can result in death, serious injury or material damage.
• Re-grease the roller bearings regularly according to the lubrication table.
• Implement bearing temperature monitoring if not yet in existence.
OPERATION TEMPERATURE.
The electric motors still operating under normal conditions reach
high temperatures. This is why motors are designed to withstand high
temperatures, and although some places may feel hot to the touch, the
motor may be operating within the limits. Use a thermocouple to measure
the temperature in the winding when there is any concern about it.
The total temperature, not the temperature rise, is the measure of
safe operation. Investigate the winding operating conditions. The total
temperature should not exceed of:
Safety information for explosion-protected
motors in operation.
WARNING
Explosion hazard
These explosion-protected machines are not suitable for hybrid
explosive environments.
This can result in death, serious injury or material damage.
Use in atmospheres where there is a risk of explosion caused by both gas
and dust simultaneously is absolutely prohibited.
Unrestricted
230°F (110°C) for class "B" insulation
275°F (135°C) for class "F" insulation
302°F (150°C) for class "H" insulation
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