6 Care and Maintenance
6.3
Troubleshooting (cont’d)
Malfunction
Possible cause
Action
Fan does not accelerate.
Improper connection of drive
motor.
Check connection.
Motor does not change from star
to delta connection.
Shorten change-over time
from star to delta.
Fan operates against insufficient
plant resistance.
Close dampers or install
additional plate shutters.
Motor protection system is not
strong enough.
Cable cross section and
protective system must withstand
starting current during
acceleration.
Starting time is too long.
Close dampers, check starting
torque of MA/MN motor.
Faulty drive motor.
Check motor and replace if
necessary.
Motor too warm due to extensive
operating frequency
Run the fan in continuous
operation and control the flow
with dampers or variable speed
control
Starting current too high..
Wrong voltage.
Provide star-delta starting,
local mains not strong enough.
