Question

Prepare troubleshooting chart for transformer as per IS- 10028-1981 (4 trouble) and Induction motor (4 troubles). 

Answer 1

Sr.no	Troubles	Causes	Remedial Measures
1	Transformer does not show output voltage	1. Primary side fuses blown out 2. Circuit breaker may trip. 3. Loose contact of tap changer, 4. Loose connection at bushing 5. Connection may be open in bushing. 6. Failure of primary winding.	Rectify the Cause
2	Incorrect secondary voltage	1. Improper turns ratio 2. Abnormal primary voltage 3. Shorted turns. Wrong setting of 4. Faulty OLTC	Rectify the Cause
3	Unequal voltage on secondary side	1. Unbalance Loading. 2. Single phasing. 3. Unsymmetrical fault	Rectify the Cause
4	Overheating of transformer	1. High input voltage 2. Overloading. Low liquid level. 3. More accumulation of sludge in oil. 4. Failure of cooling System. 5. High ambient temperature.	Rectify the Cause
5	High exciting current	1. Short circuited core 2. Open core joints 3. Poor magnetic coupling 4. Low/high frequency 5. Shorted turns	Rectify the Cause
6	Short circuit between adjacent turns (Turn to turn fault)	1. Insulation failure between turn to turn 2. Fluctuating load. 3. Transient overvoltage. 4. Moisture in oil Over heating	Rectify the cause.
7	Rapid deformation of oil/Low dielectric strength of oil	1. Presence of dissolved moisture content. 2. Presence of water content. 3. Presence of dissolved gases content. 4. Presence of acidic content. 5. Presence of sludge content 6. Presence of carbon deposits content. 7. Presence of dirt & dust content. 8. Presence of sulpher content 9. Presence of acetones content. 10. Presence of dissolved oil decay products content	Rectify the causes.
8	Incorrect oil level (oil level to low)/Leakage of transformer liquid	1. Due to leakages through gasket or tank or drain valve. 2. Leaks around transformer Accessories 3. Leakage can occur through screw joints, welds, casting, pressure-relief device, and so on. 4. The main causes are improper assembly of mechanical parts 5. Insufficient tightness of mechanical parts.	Rectify the Cause
9	Noise/vibration	1. Loose clamping of core. 2. Bad/loose foundation nut bolts 3. Magnetostriction. 4. Mechanical vibrations of tank valves. 5. Low/high input frequency	Rectify the Cause
10	Bushing failure	1. Flash over due to dirt accumulation on bushing. 2. Lightning stroke. 3. Mechanical injury to bushing 4. Improper bolting of bushing 5. Harsh environmental condition	Rectify the Cause
11	Excessive core heating	1. Due to high magnetizing current 2. High inrush current	Rectify the Cause
12	Transformer body gives shock	1. Insulation resistance reduced. 2. Any live wire touches the transformer tank (Earth fault).	Rectify the Cause
13	Winding insulation failure	1. Failure may be due to a short-circuit Fault, 2. Lightning, Overload 3. Over current condition, 4. Transformer liquid containing moisture and contaminants.	Rectify the Cause
14	Unexpected voltage to earth measurement	Earth failure on one phase.	Rectify the Cause
15	External Short circuit	1. It may be due to insufficient clearance on overhead line. 2. Accumulation of dust on insulator (Transformer bushing).	Rectify the Cause
16	Internal Short circuit	1. Continuous overloaded transformer, due to this temperature increases so, possibility of insulation failure. 2. Fault in tap changer. 3. Loose connections, causing local overheating. 4. Vibration on Insulation resulting internal short circuit	Rectify the cause.
17	Pressure-relief diaphragm broken	1. Due to an internal fault causing excessive internal pressures 2. The transformer liquid level being too high 3. Excessive internal pressure due to over loading of transformer.	Rectify the cause and replace Pressure-relief diaphragm
18	Carbon & other conducting particles in oil	1. Sparking. 2. Excessive temperature of oil	Rectify the Cause
19	Oxidation of oil	1. Mainly due to exposure to air 2. High operating temperatures.	Rectify the Cause
20	Internal arcing	1. Low liquid level 2. Loose connections, 3. Failure of the transformer dielectric.	Rectify the Cause
21	Transformer switching equipment troubles	1. May be excessive wearing of contacts, 2. Mechanism Over travel, 3. Moisture condensation in mechanism liquid.

Answer 2

Troubleshooting chart for I.M. :- 

Sr.No	Type of fault/abnormal conditions/Troubles	Causes	Remedies
1	Motor fails to start or not accelerate (Faults in starting supply circuit) Motor Switch ON but does not start	1.Blowing of fuse/tripping of MCB 2.Terminal voltage too low 3.Defective starting mechanism 4.Protection devices has been tripped 5.The motor controller will not operate 6.Open circuit in supply cable. 7.Overloaded 8.Loose contact. 9.Motor rotor, bearings or driven load is locked. 10. Bearing is seized (Frozon). If ask Single phase motor add this point 11. Open in auxiliary winding. 12. Open in main winding. 13. Open capacitor. 14. Shorted capacitor.	Rectify The Cause
2	Motor stalls	1.Terminal voltage too low 2. Over load 3. Wrong application 4. Single phasing	Rectify the Cause
3	Motor does not pick up rated speed /Motor runs but dies down/ Motor does not come up to speed	1. Starting load is high 2. Low Voltage 3. Low frequency 4. Broken rotor bars or loose rotor	Rectify the Cause
4	Run Slow (Motor starts Sluggishly)	1. Low voltage. 2. Low frequency. 3. Overload 4. Single phasing. 5. Stator connected in star instead of delta. 6. Improper connection of motor leads to supply line 7. Shorted stator coils	Rectify the Cause
5	Run Hot/ Thermal overload/ Motor overheating/ Motor frame Hot to touch (Winding Overheating)	1. Over/Under voltage. 2. Unbalance voltage 3. Over/Under frequency 4. High ambient temperature 5. Ventilating Fan is not working 6. Poor motor ventilation/ Air flow obstructed or inadequate ventilation. 7. Overload 8. Single phasing. 9. Worn bearings	Rectify the Cause
6	Vibration	1. Loose iron core 2. Dynamic unbalance of the rotor 3. Mis-alignment 4. Due to bent shaft (Run out to shaft) 5. Warn out bearings 6. Incorrect Leveling 7. Loose foundation bolts	Rectify the Cause
7	Noise	1. Mis-alignment 2. Due to bent shaft (Run out to shaft) 3. Bearing properly not fit. 4. Warn out bearings 5. Incorrect Leveling 6. Loose foundation bolts 7. Cooling fan is touching on stationary part. 8. Non uniform air gap or rotor rubbing on stator. 9. Rotor unbalanced 10. Foreign matter in air gap. 11. Gears and gear trains are amongthe principal sources of noise.	Rectify the Cause
8	Bearings continuously fail	1. Mis-alignment 2. Due to bent shaft (Run out to shaft) 3. Bearing properly not fit. 4. Warn out bearings 5. Unbalanced load/ Overloaded bearing. 6. Use of poor quality of grease/lubricating oil 7. No grease/lubricating oil	Rectify the Cause
9	Bearing overheating	1. Mis-alignment 2. Due to bent shaft (Run out to shaft) 3. Bearing properly not fit. 4. Warn out bearings 5. Unbalanced load/ Overloaded bearing. 6. Use of poor quality of grease/lubricating oil 7. No grease/lubricating oil 8. Oil level too high/ low. 9. Too much grease/ No grease 10. Foreign matter in grease. 11. Excessive belt pull.	Rectify the Cause
10	Excessive sparking at brushes/slip rings	1. Loose contact 2. Warn out brushes/slip rings 3. Improper pressure and spring tension. 4. Brushes are bedding or sticking in holders-not properly 5. Dirt is accumulated on brushes/slip rings 6. Grads of brushes/slip rings material is of bad quality.	Rectify the Cause
11	Motor runs high speed	1. Voltage available is more than rated voltage 2. Load is too less.	Rectify the Cause
12	Motor runs in the wrong direction	1.Incorrect wiring. 2.Phase sequence of supply changed 3.Improper connection of motor leads to supply line	Rectify the Cause
13	Motor has been running, then fails to start	1. Fuse or circuit breaker tripped. 2.Motor overloaded. 3. Stator is shorted 4.Capacitor failure. 5. Starting switch has failed	Rectify the Cause
14	Motor takes too long to accelerate	1.Voltage too low 2.Defective Capacitor. 3. Starting switch has failed 4.Bad bearings	Rectify the Cause
15	Regular clicking (Short sound)	1. Foreign matter in air gap. 2. Dirt in motor.	Rectify the Cause
16	Scraping Noise	1. Fan rubbing 2. Fan striking insulation 3. Loose bed plate nut bolt
17	Motor hums a) During Start up b) When running	1. Unequal phase resistance 2. Open circuit 3. Inter turn short circuit on motor. 4. Short circuit between turn to turn or parts of stator winding.	Rectify the Cause
18	Abnormal Supply conditions	1.Loss of supply voltage. 2.Unbalanced supply voltage. 3.Phase sequence reversal of supply voltage. 4.Over /Under frequency 5.Over /Under Voltage 6. Single Phasing	Rectify The Cause
19	High input current in all 3 phases	1.Line voltage 10% or above /below the motor nameplate voltage. 2.Motor overloaded.	Rectify The Cause
20	Unbalanced line current on poly phase motors during normal operation.	1.Unequal terminal voltage. 2. Single phase operation 3.Unbalanced voltage	Rectify the Cause