More due to the impedance levels in the 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.
the shunt generator wont be started .hehe
it is the resistance with which the generatoe just excite.
it doesn't develop emf ..........
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.
It does have armature resistance.
1. Field Flashing. 2. Resistance of the filed winding should be less than critical field resistance. 3. Speed of the motor should be greater than critical speed. 4. Interchange the field connections. 5. Check the commutator surface and brush.
Possible reasons for failure of voltage buildup... 1) No residual Magnetism, 2) Field connection may be in reverse manner, 3) Field resistance is greater than critical resistance, 4) Speed is less than Critical speed.
shunt field winding have more resistance than series field winding ************sai ganesh ************269*******
load test on dc shunt generator is a test to plot the internal and external characteristics of the generator.
The difference between a separately excited DC generator and a Shunt DC generator is that for a separately excited Dc generator , the excitation field winding is supplied by an external source different from that supplying the armature while for shunt generator, the excitation field windind is connected in series with the armature and supplied by a single source.
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.