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What else can I help you with?
Why the armature voltage E changes when the field rheostat is varied?
This depends on how the motor and wiring. You'll need to provide more information. Series / compound / shunt / differential / self or separately excited / is the rheostat in parallel or series to the field / is the rheostat on the shunt field or series field (if compound)
Why the generator field rheostat kept at maximum position?
There is nothing to limit current until opposing magnetic fields build up at generator operating speed-windings will overheat and burn.
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
How do you start a DC motor if there is no 3 point starter?
By the use of auto transformer and bridge rectifier we can start dc motor.
Why should the generator field rheostat be kept to its maximum at starting?
Keeping the generator field rheostat at its maximum at starting helps to establish a strong magnetic field in the generator, which is essential for generating sufficient voltage to initiate the generation process. This ensures a smooth and stable startup of the generator.
Why motor rheostat kept minimum position generator rheostat maximum position?
the back emf increases so that high currents doesn't pass through the field windings
Why the armature voltage E changes when the field rheostat is varied in shunt motors?
In shunt motors, the armature voltage ( E ) changes when the field rheostat is varied because altering the resistance in the field circuit affects the field current and, consequently, the magnetic flux produced by the field winding. When the field rheostat is decreased, the field current increases, leading to a stronger magnetic field and a higher back electromotive force (EMF) generated in the armature. This results in a change in the armature voltage, as the increased back EMF reduces the net voltage across the armature. Conversely, increasing the field resistance weakens the magnetic field, reducing back EMF and allowing the armature voltage to rise.
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.
If the rheostat were connected in series with the shunt field winding and the combination placed across a 120 V dc line what shunt field current variations could be obtained from your motor?
It could be anything, it depends on the design of the motor and whether it is a high-power or a low-power motor.
How do you Test a rheostat?
how to test a rheostat?
Who invented Rheostat?
The rheostat was invented by Sir Charles Wheatstone in the early 19th century. Wheatstone was a prominent English scientist and inventor who made significant contributions to the field of electrical engineering.
What are the problems of commutation in a DC generator?
1.resistance commutation 2.e.m.f commutation
