Two things could have occurred.
(1) wrong direction of rotation causing loss of residual magnetism or
(2) loss of residual magnetism over long period of no use.
can be remedied by "flashing" the shunt field winding
howlumf
because the voltage likes to drop
load test on dc shunt generator is a test to plot the internal and external characteristics of the generator.
If there is no residual magnetism in the field poles then there would be no flux too induce the initial voltage for self exitation
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.
Differential compounded generators are used in Ward Lenard motor generator loops. The shunt fields on these generators are separately excited and when the shunt field polarity is reversed by the controller the series field helps drive the generator voltage to zero thus aiding in the reversal of current.
because the voltage likes to drop
The voltage is adjusted with a potentiometer that adjusts the field voltage through the voltage regulator.
load test on dc shunt generator is a test to plot the internal and external characteristics of the generator.
If there is no residual magnetism in the field poles then there would be no flux too induce the initial voltage for self exitation
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.
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.
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.
A shunt generator is a type of DC generator that does not use a permanent magnet. Reducing the speed of the generator will reduce the output, but not the load the generator requires because the currents in the parallel branches are independent.
Differential compounded generators are used in Ward Lenard motor generator loops. The shunt fields on these generators are separately excited and when the shunt field polarity is reversed by the controller the series field helps drive the generator voltage to zero thus aiding in the reversal of current.
Applications of Voltage shunt feedback amplifier?
In Voltage Shunt Amplifier, the Output voltage is supplied in parallel with the Input voltage through the feedback network.
it doesn't develop emf ..........