why field resistance is higher than armature resistance in
dc machines? and why filed resistance is kept at min value
at starting in same time of armature resistance at max value?
Answers were Sorted based on User's Feedback
Answer / sai
To allow the maximum current through the armature, resistance is kept to very low value. According to ohm's law, V=IR.
As R is very low then current becomes maximum.
| Is This Answer Correct ? | 21 Yes | 10 No |
Answer / lokesh luckky
It has two reasons
1) in DC generator to allow large generated currents to output.
2)in motor (torque is proportional to current) so to produce high torque we must allow high currents through winding.
| Is This Answer Correct ? | 7 Yes | 0 No |
Answer / abdelbaset
because the consumable power in the field circuit assuming
the same voltage of the main circuit is lower than the
armature circuit. so the excitation current is lower than
armature current so field resistance is greater than
armature resistance
| Is This Answer Correct ? | 11 Yes | 16 No |
Answer / binod
field resistance always more than the armature resistance
of a d.c machine(shunt or series or compound).magnetic flux
created by field.to vary generate e.m.f the field
resistance vary from min to max with increase/decrease of
speed.in motor case the speed can be vary by varrying the
field resistance(addition or substraction) with the
required torque.
| Is This Answer Correct ? | 6 Yes | 19 No |
As Electricity Generates in MW I w'd like to know What are the factors we have to consider regarding the transmission of electricity from generation station to Public uses(230 V)
Explain the working of variable frequency transformer?
why normally Generator rating are between 11Kv to 22Kv?
Can the Neutral and Body Earthpits of a transformer conncted together by Earth strips under ground.
please tell me formula of 3 phase induction motor under condition{1]when we 3 phase motor starts without load in star or delta connection?thanks
difference between fleming's left hand rule and RHR briefly.
Why 30kw 40 hp 4 pole 3ph induction motor over heated?any steps on reduction in heat?
in a 740 kw dc seperately excited motor field voltage is constant about 17.4 volts and armature voltage is500 volts dc. how it is possible to have two different voltages from single transformer of output voltage 500 volts? if any difficulty in question contact ajitsingh.kadian@gmail.com
electricity requires a medium to flow and it cannot flow through air. so how does lightning come to earth through air without any medium?
What is the knee point of voltage of CT?
Why DC weldings sets preffered over AC considering human safety aspects ?
What is kvar?
Civil Engineering (5086)
Mechanical Engineering (4456)
Electrical Engineering (16639)
Electronics Communications (3918)
Chemical Engineering (1095)
Aeronautical Engineering (239)
Bio Engineering (96)
Metallurgy (361)
Industrial Engineering (259)
Instrumentation (3014)
Automobile Engineering (332)
Mechatronics Engineering (97)
Marine Engineering (124)
Power Plant Engineering (172)
Textile Engineering (575)
Production Engineering (25)
Satellite Systems Engineering (106)
Engineering AllOther (1379)