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because there is ahigh current flowing through it at the start...
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What will happen if field rheostat of dc shunt motor is kept at maximum position while starting?
First remember this rheostat is connected in series with the armature to increase the total resistance to limit the starting current, thus achieving max starting torque from the motor
What is critical resistance of the field circuit of a DC generator?
The value of resistance of shunt field winding beyond which the shunt generator fails to build up its voltage is known as " critical resistance at a given speed it is the maximum field resistance with which the shunt generator excite.
What is DC shunt motor?
A shunt DC motor connects the armature and field windings in parallel or shunt with a common D.C. power source. This type of motor has good speed regulation even as the load varies, but does not have the starting torque of a series DC motor
How do you select field rheostat range for dc motor?
For a shunt dc motor the rheostat would vary from zero ohms to a value that produces the required minimum field current, but rheostats are not common with shunt motors except as a crude way of controlling the speed. Series dc motors normally use rheostats for starting, especially in trams etc. because the starting torque and current is very high. The rheostat resistance starts at a value equal to the supply voltage divided by the maximum allowable current drawn, and is reduced as the speed builds up.
Is 4 point starter used to start and control the speed of dc shunt motor with armature resistance control?
yes
What will happen if field rheostat of dc shunt motor is kept at maximum position while starting?
First remember this rheostat is connected in series with the armature to increase the total resistance to limit the starting current, thus achieving max starting torque from the motor
What is critical resistance of the field circuit of a DC generator?
The value of resistance of shunt field winding beyond which the shunt generator fails to build up its voltage is known as " critical resistance at a given speed it is the maximum field resistance with which the shunt generator excite.
Why motor has large winding in shunt resistance than armature resistance?
A motor with large windings will have greater shunt resistance than armature resistance due to the sheer amount of copper wire it must travel through. The gauge of the wire also plays a part in this process.
What is DC shunt motor?
A shunt DC motor connects the armature and field windings in parallel or shunt with a common D.C. power source. This type of motor has good speed regulation even as the load varies, but does not have the starting torque of a series DC motor
Is 4 point starter used to start and control the speed of dc shunt motor with armature resistance control?
yes
How do you select field rheostat range for dc motor?
For a shunt dc motor the rheostat would vary from zero ohms to a value that produces the required minimum field current, but rheostats are not common with shunt motors except as a crude way of controlling the speed. Series dc motors normally use rheostats for starting, especially in trams etc. because the starting torque and current is very high. The rheostat resistance starts at a value equal to the supply voltage divided by the maximum allowable current drawn, and is reduced as the speed builds up.
Why shunt resistance is connected in the parallel?
Shunt means parallel only..................
How will a shunt generator behave if the field resistance is greater than the critical resistance?
the shunt generator wont be started .hehe
Why dc shunt generator does not have armature resistance?
It does have armature resistance.
What happen in shunt motor speed if the resistance is increased?
Its performance becomes worse. The speed will drop more when a mechanical load is put on the shaft.
What is a DC shunt motor?
A DC shunt motor is a motor using DC supply with the the inductor connected parallel to the armature.
Why can we start a shunt motor under no load but why can't a series motor?
The torque on a series motor is determined by the square of the armature current and, so, is very large -much larger than that of a shunt motor. Consequently, on starting, with no back-emf being generated, the torque on a series motor can be dangerously high if the machine has no mechanical load.
