What will be the effect of reducing load on separately excited DC motor?
I assume you are referring to a motor that has separate supplies to the field and armature. If the voltage applied to the field and the armature remain the same, increasing the load will reduce the armature speed. This will reduce the reverse voltage in the armature that limits the current.
What is the influence of the load of a separately excited DC motor on the speed in the case of constant armature voltage?
in a separately excited DC motor with armature voltage speed control, if the torque is increased and all other perimeters are left alone (i.e. the Armature voltage is not manually changed), the speed of the machine and armature voltage decreases.
What is the function of the load?
Load affects the performance of circuits with respect to output voltages or currents, such as in sensors, voltage sources, and amplifiers. Mains power outlets provide an easy example: they supply power at constant voltage, with electrical appliances connected to the power circuit collectively making up the load.
What are three speed control methods for separately excited dc?
Thus, there are three general methods of speed control of D.C. Motors.
- Resistance variation in the armature circuit: This method is called armature resistance control or Rheostat control.
- Variation of field flux Ф This method is called field flux control.
- Variation of the applied voltage.
Which is a disadvantage of a separately excited DC generator?
In a separately excited dc generator, the field coils are energized from an independent source. The disadvantage of a separately excited DC generator is the same that we require an external DC source for excitation.
When does a separately excited DC generator have an EMF?
When the field current is zero, for the effect residual magnetism in the poles, there will be a small initial emf (OA) as show in figure. Let us consider a separately excited DC generator giving its no load voltage E 0 for a constant field current.
What happens when the load of a generator is increased?
The ‘load’ is the power drawn from the generator. Once you get that definition, the rest should be clear. When load is increased the armature current is increased and the terminal voltage and speed decreased due to the voltage drops in the armature resistance and armature reaction
How is the O.C.C of a separately excited generator determined?
But since the output voltage may be controlled more easily and over a wide range (from zero to a maximum), this type of excitation finds many applications. The O.C.C. of a separately excited generator is determined in a manner described in the previous section.