Because of their self-regulating speed capabilities, DC shunt motors are ideal for applications where precise speed control is required. Keep in mind, however, that they cannot produce high starting torque, so the load at startup must be small.
What is a DC shunt motor used for?
DC Shunt Motor Applications
These motors are used wherever stable speed is required. This kind of DC motor can be used in Centrifugal Pumps, Lifts, Weaving Machine, Lathe Machines, Blowers, Fans, Conveyors, Spinning machines, etc.
What are the characteristics of DC shunt motor?
Characteristics of a DC Shunt Motor:
- Speed-Armature Current Characteristic: …
- Torque-Armature Current Characteristic: …
- Speed-Torque Characteristic: …
- Break in Field Circuit of a DC Motor:
Why DC shunt motor is started on no load?
For DC shunt motor the field resistance is high and armature resistance is low so the variation of flux is very less when rated voltage is applied to the motor and motor speed does not exceeds rated speed at no load. So we can start the DC shunt motor with no load.
Why DC shunt motor is constant speed?
Since torque is proportional to armature current, torque also increases. Finally, this increased torque allows the motor to increase its speed and compensate for the slowdown due to loading. Hence, a DC shunt motor is able to self-regulate its speed, and can be referred to as a constant speed motor.
What are the advantages of DC motor?
DC motors have the advantage of: higher starting torque, quick starting and stopping, reversing, variable speeds with voltage input and they are easier and cheaper to control than AC. AC motor advantages include: lower power demand on start and minimal maintenance.
What will happen if excitation of DC shunt motor is changed?
What will happen if excitation of DC shunt motor is changed? Explanation: The motor will accelerate the mechanical load connected during this period but no increase in the mechanical load as Pload = T1W1 = T2W2 where W2 >W1. So, at the higher speed there is less electrical torque for the same mechanical load / power.
What is a DC shunt?
Direct current instrument shunts are used to extend the range of ammeters whenever the current to be measured is too large to be passed through the instrument–usually currents over 50 amperes. The shunt, therefore, is a diverter which is used to “shunt” the majority of the current around the indicating instrument.
What is the main disadvantage of a shunt motor?
Disadvantages of DC Shunt Motors
Installation of DC machines is expensive compare with other types of machines. Since Shunt motors are constant speed motor, it would be a disadvantage where it’s necessary to operate under variable speed.
What will happen when the field of a DC shunt motor gets opened while the motor is running?
If the shunt field suddenly opens while the motor is being operated under full-load conditions, only a small voltage due to the residual magnetism of the pole pieces will be induced into the armature. Current will increase considerably. The magnitude of this current may be sufficient to burn out the motor.
Why the efficiency of DC shunt connected motor is low when it is running at low load?
A DC shunt motor (also known as a shunt wound DC motor) is a type of self-excited DC motor where the field windings are shunted to or are connected in parallel to the armature winding of the motor. Since they are connected in parallel, the armature and field windings are exposed to the same supply voltage.
How do you control the speed of a DC shunt motor?
Speed control of Shunt motor
- Flux control method. It is already explained above that the speed of a dc motor is inversely proportional to the flux per pole. …
- Armature control method. …
- Voltage Control Method. …
- Flux control method. …
- Variable resistance in series with armature. …
- Series-parallel control.
What will happen if a shunt DC motor is directly connected to the supply line?
What will happen if DC shunt motor is connected across AC supply? Explanation: In case of parallel field connection, it won’t rotate at all and will start humming and will create vibrations, as a torque produced by positive and negative cycle will cancel out each other. DC motor will be heated up and it may burn. 2.
What is the difference between a shorted motor and a shunt motor?
What is the difference between a shorted motor and a shunted motor? A shunt motor has the field windings connected in parallel with the armature and a series motor has the field windings connected in series with the armature15.