Vents VKV User Manual page 17

Problem
The fan will not start.
The switching equipment
activates upon fan start-up.
The fan fails to reach the
required rotation speed due to
serious overheating of the fan
motor.
The fan motor runs at
overload capacity with current
consumption in excess of the
rated value.
The fan supplies more air than
expected.
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TROUBLESHOOTING
Possible reasons
No power supply.
Jammed motor.
Short circuit in the fan or the electric circuit between
the fan and the switching equipment.
Excessive current consumption due to an overload in
the electric mains.
Improper fan starting method.
Improper switching equipment.
The installed switching equipment is of poor quality
or its actual performance falls short of the rated values
stated by the manufacturer.
Fan motor overloaded.
Improper fan starting method.
The fan supplies more air than expected upon motor
capacity selection.
Wrong motor phasing. The impeller rotates in the
opposite direction of the arrow on the fan casing.
Air ducts clogged.
The resistance values used during the ventilation
network calculations are too conservative.
The cross section of air ducts increased and their
number reduced during the installation.
Wrong choice of the fan.
Elimination
Check the mains switch. Check the electrical connections
according to the wiring diagram.
Carefully check the fan impeller for possible seizure and
eliminate it, if necessary. If the impeller is in order, replace
the electric motor.
Eliminate the cause of a short circuit.
Eliminate the cause of excessive current consumption.
Use a soft starter or frequency converter to start the motor
(see "Asynchronous Electric Motor Starting Methods"
in the "Connection to power mains"
Re-select the switching equipment in accordance with the
current regulations and equipment specifications.
Re-select the switching equipment by choosing a unit
which successfully passed commutation and load tests
and has a technical compliance certificate. The selection
should be limited to the top five foreign switching
equipment manufacturers.
Eliminate the overload.
Use a soft starter or frequency converter to start the motor
(see "Asynchronous Electric Motor Starting Methods"
in the "Connection to power mains"
Measure network resistance. Throttle down the network
(add aerodynamic resistance to the air duct network).
If necessary, change the impeller rotation direction by
changing the phase sequence on the electric motor
terminals.
Clean the air duct or the impeller.
Check the air ducts for proper shape and cross section as
well as for any dampers present.
Throttle down the network (add aerodynamic resistance
to the air duct network).
Replace the fan with a unit of proper standard size.
section).
section).
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