Kruger BNA General Instructions Manual page 5

Fan does not start or operate
Electrical Supply





Motor 



Drive System 

Excessive air flow
Fan 
Excessive rotational fan speed
Duct System 
Pressure resistance offered by the system lower than
the design value
Gas Density 
Gas density higher than the design value
High power absorption
Impeller 

Motor 

Fan 
System 



Gas Density 
Fan selection 
Possible cause
Blown fuses
Electricity turned off
Wrong voltage
Failure of one or two phases
Low voltage, excessive line drop or inadequate wire
size
Motor not correctly connected
Load inertia too large for motor
Motor protection unit or switch are stopping as
temperature are too high
Motor too small and overload protector has broken
circuit
Broken belts
Loose pulleys
Possible cause
Possible cause
Air flow already rotating in the opposite direction to
the fan rotation direction
Backward curved impeller installed backwards
Faults in the motor windings
Motor power supply voltage lower than the value
indicated on the identification plate
Forward curved or backward blade fan operating
below design pressures.
Oversized ductwork
Filter(s) left out
Access door are open
Face and by-pass dampers oriented so coil dampers
are open at same time by-pass dampers are open
Calculated horsepower requirements based on light
gas (eg. High temperature) but actual gas is heavy
(eg. Cold start up)
Fan not selected at efficient point of rating
 Check fuses/circuit breakers

Check for switched off or disconnected

Check for correct power supply

Check for correct power supply

Check for correct wire size

Connect the motor according to the motor label

Change motor

Reduce temperatures, check and change
insulation class, increase motor rating

Change motor

Replace belt

Tighten pulley

Reduce fan speed

Replace motor

Check with motor supplier

Redesign ductwork

Add in filter(s)

Close access door
 Check selection
5
Remedy
Remedy
Remedy