Self-excited, shunt DC generator operating at no load The magnetization curve produced when the machine is separately excited still applies. Because the load current is zero, the only current in the armature winding is the field current.
What will happen when DC series generator is started without load?
If there is no load is connected to series generator the current in the field winding would be absent and there by no flux is available for voltage to be generated. Hence you need to load the generator.
Can a DC series generator excite on no load?
What is DC Series Motor? Armature current of any DC motor depends upon load. Hence if load increases armature current (Ia) also increases and vice versa. At no load condition, load on the motor is zero hence armature current(Ia) is also zero.
Why should dc series motor started with load?
But practically the motor will accelerate to very high speed , which will damage the motor. But if you start the motor with the load, you are actually reducing the starting speed hence the motor runs safely. Since series motors has this property it is used in trains to pull high load.
What happens when the load from a series motor is suddenly taken off?
So, if the load is suddenly thrown off, the motor will tend to rotate and dangerously high speed. Thats the reason why the series motors are always chain or belt driven.
Which DC motor has maximum self loading property?
Which DC motor has got maximum self-loading property? Explanation: A differentially compound DC motor, flux reduces so sharply at small increase in load at higher values of load.
Can we start DC shunt and DC series motor without load?
You can start a DC shunt motor without a load, but never start a DC shunt motor with heavy load because, The change in field flux is very less due to the load, so we can assume the flux to be constant.
Why is there an armature voltage even when the field current is zero?
It is due to the property of the field component, called “residual magnetism”. Since the field windings are made up of ferromagnetic material, it will not falls down its magnetic flux to zero even after the current through that become zero, but it retain a non zero value of magnetic flux in it.
What happens if we increase the load in a series field DC generator?
It can be observed from the characteristics of series wound DC generator, that with the increase in load (load is increased when load current increases) the terminal voltage of the machine increases. But after reaching its maximum value it starts to decrease due to excessive demagnetizing effect of armature reaction.
Why does OCC look like BH curve?
However, as the flux density increases, the poles get saturated and the ɸ becomes practically constant. Thus, even we increase the If further, ɸ remains constant and hence, Eg also remains constant. Hence, the O.C.C. curve looks like the B-H characteristic.
What are the advantages of DC series motor?
Advantages of DC Series Motor
- Dc series motor have good accelerating torque.
- Dc series motor have a relatively huge starting torques.
- Dc series motor delivers high torque during an overload.
- The dc series motor draws less current and power from the source compared to a shunt or compound motor.
Which type of load is connected to the DC series motor?
A series DC motor connects the armature and field windings in series with a common D.C. power source. The motor speed varies as a non-linear function of load torque and armature current; current is common to both the stator and rotor yielding current squared (I^2) behavior.
How can the speed of a DC motor be controlled?
Thus, the speed of a DC motor can be controlled in three ways: By varying the supply voltage. By varying the flux, and by varying the current through the field winding. By varying the armature voltage, and by varying the armature resistance.
When load is removed motor will run at the highest speed?
1 Answer. When load is removed, series motor will run at the highest speed.
Which motor has the poorest speed control?
Which of the following DC motor has the poorest speed control? Explanation: DC series motor at no load condition gives infinite speed ideally. Practically it will damage all the armature circuit.
What will happen if excitation of DC shunt motor is changed?
2. What will happen if excitation of DC shunt motor is changed? … Explanation: Speed of the DC motor obtained from speed equation is inversely proportional to flux produced by the field. So, reducing the field current flux produced by armature will decrease, and speed will increase.