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11.1 Protecting the motor
Important
Damage to motor due to overcurrent, overload or short circiut.
♦
Lead-out temperature monitors must be integrated in the control circuit in such a way that, if a fault
occurs, the motor cannot switch on again automatically after it has cooled down.
♦
Motor lines and temperature monitor lines should be laid separately on principle.
♦
Without thermal protection: Use a motor protection switch!
11.2 Variable-speed fans
Warning
Resonant frequencies may result in increased vibration in certain speed ranges. These vibrations may
destroy components.
♦
Only operate the fan outside these speed ranges.
♦
Pass through these speed ranges so quickly that any vibration cannot exceed the admissible resonant
frequency values.
♦
Observe the operating instructions of the frequency converter.
Caution
Damage as a result of incorrect commissioning of the frequency converter.
♦
Install the fan and frequency converter as near as possible to one another.
♦
Use shielded cables.
♦
All components (fan, frequency converter and motor) must be grounded.
♦
We recommend using all-pole sinus filters.
♦
Avoid running the fan via the frequency converter below 10 Hz.
♦
Heating of the motor due to use of a variable frequency drive must be checked in the application by the
customer.
♦
Never exceed the maximum impeller rotation speed indicated on the name plate of the fan.
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