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There is nothing to limit current until opposing magnetic fields build up at generator operating speed-windings will overheat and burn.
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What are the differences of Long shunt vs short shunt generator?
In long shunt the shunt field winding is in parallel to both generator and series field. In short shunt the shunt field is in parallel to generator only.
What are the values of armature and field rheostat to be maintained during starting of a d.c motor?
you want full field while starting 0 Ohms and maximum series on armature then bring the armature resistance to zero as it approaches running speed its a good idea to run with armature at 0 ohms armature will use the same amount of power as the resistor If you want to run at more than base speed you can now weaken the field
Can you use the separately excited shunt generator machine as self excited generator?
You have a seperately excited generator and then you have a shunt generator which has the field winding in parallel with the armature terminals. In DC machines a separately excited generator could be run as a shunt generator provided the field winding is designed to work on the generated voltage. A separately excited alternator needs a DC supply for the field winding. In car alternators that is taken from the main winding via a rectifier and a voltage regulator.
How does a generator exciter work?
Exciter controls the magnetic field in the generator system and controls the output voltage and/or current.
How does the starting of synchronous motor using dc generator as a load work-?
Starting of the synchronous motor using the DC generator creates a magnetic field.
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
When the rheostat position is changed from minimum position to maximum position in motors what will happens?
the back emf increases so that high currents doesn't pass through the field windings
Why is the field rheostat of a DC motor kept at minimum position while starting?
If you are talking about the field rheostat on a generator, once you have the correct voltage output set, it is very unlikely that it has to be touched again. If it is the generator's first start up, then it is best to set the field on the low side so as not to over excite the generator and drive the output voltage higher that what the generator's specifications are rated at. The field excitation voltage does not have to be set at the minimum position on every start up once it is set for the correct output voltage. A good example of this is a hospital standby generator, it starts up with no human intervention needed.
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 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)
Define the term critical field resistance?
critical resistance is the maximum resistance beyond which the generator failed to exite. it can b found form the occ of the generator.
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.
What are the differences of Long shunt vs short shunt generator?
In long shunt the shunt field winding is in parallel to both generator and series field. In short shunt the shunt field is in parallel to generator only.
Answering Which one is a separately excited generator - ac generator or dc generator?
Excitation is the phenomenon by which you control the excitation of field winding of a generator. In DC generator field winding is placed on stator and this field winding can be self excited or seperately excited depending upon the type on generator used. AC generators can also be self excited or seperately excited type but field winding is placed on rotor nad armature winding on stator.
Is the critical resistance of shunt field less or more than the field resistance of generator?
More due to the impedance levels in the generator
What is a shunt generator?
A shunt generator is a method of generating electricity in which field winding and armature winding are connected in parallel, and in which the armature supplies both the load current and the field current.A direct current (DC) generator, not using a permanent magnet, requires a DC field current. The field may be separately excited by a source of DC, or may be connected to the armature of the generator so that the generator also provides the energy required for the field current.
