Even motor protection, why motor burn out ?
Answer Posted / atul naik
Its not 100% true. Actually Motor has been protected many
a times before it actually burns. But either we have
ignored the actual reason of tripping by resetting OL
Relay or by removing the Over Load on Motor.
Still Motor Burns. So it is observed that following reasons
are there. 1 Dips in Supply Voltage, 2 Frequent Over Loads
reduces the performance/ sensitivity of OL Relay 3 Short
Ckt Protection is Not there (ANSI 50 & 50N )4 Short Ckt
Protection is Not Fast or delayed ( to avoid Nusence
tripping in Starting )5 Impairing of an Insulation due to
entry of unwanted gases,liquids etc,Reducing the Insulation
Strength of the Motor.,6 Wornout bearings, it will not only
oppose the motion and create resistance but also it
increases the heat / temp. 7 In case of CT Operated
Relays , CTs may reduce senstivity. Now, the cumulative
effect is that Fault Clearing Time is More than the Temp
rise time due to Fault , due to which Motor insulation
fails and motor winding no longer remain healthy ie Motor
burns.
Is This Answer Correct ? | 19 Yes | 1 No |
Post New Answer View All Answers
what is the disadvantages of common earthing for AC and DC equipment? (i am talking about inverter control room and inverter duty transformer earthing is common...?)
why the earth is taken minimum in supplying? wather it the proportional factor to getting work any equipment or a power plant?
fuel-air ratio in a petrol engine fitted with suction carburettor,operating with dirty air filter as compared to clean filter will be
i want to know about torque of slip ring induction motor
During underground cabling in landscape area what did we cover the cable with to prevent the electric shock & protect the cable?
what is negative d.c. voltage, why this voltage is used in base transciever station.
Is there any standard guidelines/Criteria to design NGR/NGT.?
What is the differentional relay...what is the work of this in power Tx. how it is works..
what types of electrical & mechanical test conducted in switchyard?
Pl. brief about break-down maintenance of machine tool.
The synchronous machine excitation system explain
high voltage transformer input voltage,current and amps rating..distributed transformer input voltage,current and amps rating...
differnce between single acting and double acting solenoid valves
why we have to particulary use ACB for below ratings,even available of MCB,MCCB with that range ?
HOW MANY TYPES OF FUSE?