Troubleshooting - Kruger ADA Series General Instructions Manual

The fan may now be put into operation but during the first 8 hrs of running, it should be periodically
observed and checked for excessive vibration and noise. Checks should be make of motor input current and
motor & bearing temperature to ensure that they do not exceed manufacturer's recommendation. After 8 hrs
of operation, the fan should be shut down to check the following items :-
(1) All set screws and hold-down bolts
(2) Belt drive alignment
(3) Belt drive tension
(4) Bearing housing temperature
After 24 hrs of the satisfactory operation, the fan should be shut down, and the drive belt tension should be
readjusted to recommended tension.
TROUBLE-SHOOTING
Fan is developing or emitting abnormal or excessive noise
Drive system 
Fan or motor sheave not properly tightened onto shaft

Misalign sheaves

Belt hitting Belt Guard

Belts are not tensioned enough and are too loose

Belts too tight

Belts wrong cross section

Belts worn

Belts oily or dirty

Belt guard is not properly fastened

Motor, motor base or fan not securely anchored or
Secured
Motor 
Lean-in cable not secure

Noisy motor bearings

Single phasing a 3 phase motor

Low voltage

Cooling fan striking shroud

Electromagnetic fault in motor

AC hum in motor or relay

Starting relay chatter
Fan Components
 Impeller loose on shaft

Impeller unbalance

Impeller not center in inlet or housing

Impeller in contact with inlet cone

Blades rotating close to structural member

Cutoff or other parts loose (rattling during operation)

Cutoff damaged

Cutoff improperly positioned

Impurities or foreign material inside fan housing

Bearing defective or worn out

Bearing loose on bearing support or shaft
 Foreign material inside bearing

Fretting corrosion between inner race and shaft

Bearing not sitting on flat surface

Rubbing noise between bearing seal and inner ring

Impeller worn as a result of abrasive or corrosive
material moving through passages.

Blades coinciding with an equal number of structural
members
Possible cause

Remedy

Re-tightened the sheaves

Re-align the sheaves
Check fan & motor sheave alignment & belt tension

Increase the belt tension

Correct belt tension

Change to right type

Replace belts

Clean belts

Tighten the fasteners

Tighten the fasteners

Fasten the cable properly

Replace bearing

Check power supply

Check power supply

Check motor assembly

Replace motor
 Tighten impeller

Balance impeller

Adjust impeller to center of inlet or housing

Correct inlet cone position

Correct the running clearance

Tighten loose parts

Replace cutoff

Reposition cutoff

Clean inside fan and impeller

Replace bearing

Re-tighten bearing
 Clean bearing

Replace bearing or shaft

Re-adjust bearing

Replace bearing

Replace impeller