Answer / abhishek ranjan

when we connect dc motor to ac supply. the moter will rotate
but high heat is devlops which can cause damage in armature
winding and brushes.......

Answer / jishnu

it depends on the winding connection with the armature
1. connected in series
the motor works normally as same
as the DC series motor

2.connected in parallel
the motor will not rotate because the torque
produced in the rotor due to ac is equal and opposite in
magnitude and direction hence resultant torque produced in
rotor is zero

Answer / parth belani

It will run. heating will take place which will damage the
motor if it is given AC supply for longer duration.
when AC supply is given to DC motor, the direction of the
magnetic field as well as the direction of the current in
the armature will be reversed in the second half of the AC
cycle. so, the direction of the torque will remain the same
in both the halves of the AC cycle. and motor will run.

Answer / makga

is either you will distroy the motor and protection device
of DC and AC are not same. torque of ac is lower than of DC
motor. if you do that you will burn the motor

Answer / a

Nothing will happen connect a DC motor to a cycle
dynamo.when ac wave will match the motor polarity +- it
will rotate in the direction it needs to CW or CCW as soon
as the wave will change it will try to move in the other
direction hence ... givein only some viberations....

Answer / b.dayakar reddy

>>When A.C. supply is given to a D.C. motor,




1)In case of Series connection of armature winding and field winding , it may run. 
2)But, In case of parallel connection , it won't rotate at all and will start humming and will create vibrations, as a torque produced by positive and negative cycle will cancel out each other. D.C. motor will be heated up.

Answer / raghavendra

It will rotate......
Universal Motor is an example for a DC motor works for AC
power

Answer / abdullah mohammed

if the protection does not work the motor will be damaged
if it work for long period

Answer / kaushik

In case of dc motors ,if provided with ac supply will run because in every halfcycle the polarity of field and armature winding will change simultaneously so that torque will be in same direction (regardless wether it is series or shunt motor) but the field winding will be hotter as they are not laminated (as they are designed for working with dc) so excess heat will produce due to eddy current.

Answer / osho katyal

It wont work since pole field mmf is stationary and ac
supply wont be able to lock itself with the sttaionary
pulsating field,so rotor cant move

What is the lifetime of a Thyristor? Is there a recommended lifetime for thyristors after which they should be replaced?

0 Answers  

If we give 2334 A, 540V on Primary side of 1.125 MVA step up transformer, then what will be the Secondary Current, If Secondary Voltage=11 KV?

3 Answers   L&T,

I am B.E.electrical engineer having 7 years of experience in Transformer testing upto 315 MVA.I want to khow how I can get the 'Electrical Valuer' License.

0 Answers  

What is the diffrence (Technical & Construction ) between CBCT & Normal CT?

0 Answers  

What is BMS System???Types...

4 Answers   Emerson,

how u calculate ups battery backup

2 Answers  

what meaning of gd squre

1 Answers  

WHY THE DIMENSION OF TWO SAME RATED MACHINE IS DIFFERENT ?

0 Answers  

In an electrical power supply,why if neutral phase of a 3phase supply fail over current occur but if it's single phase supply neutral phase fail low current occur? 

1 Answers  

When we have earthing mesh or underground earthing network in industrial plants, weather we have NT-S or NT-C-S kind of earthing system, so eventually weather we must use 4 or 5 wire in 400 volt level (For example 3×150+70 mm2 or 5×150 mm2) in this connection I would like to know exactly the paragraph of IEC or IEEE number

0 Answers   TATA,

Is there any decided or standard frequency to check the meager testing of transformer, DG set, LT Panel in the industries in a year. I means how many times we should be check the same.

2 Answers  

Can anyone tell me how a 12v battery is transformed to 20,000v at the spark plug

6 Answers