The rotating speed of an electric motor depends on two factors: its physical construction, and the frequency (Hz) of the voltage supply . Electrical engineers select the speed of a motor based on the needs of each application, similar to how the mechanical load determines the horsepower required.
What are the factors on which speed of motor depends?
The electric motor speed depends on both the applied voltage and the number of turns of its coil . The more turns the motor has the higher the strength of the rotor magnetic field if the current is maintained constant.
Which factor affect the speed of rotation of a DC electric motor?
1 Answer. The speed of rotation of the coil in a D.C. motor can be increased by: (i) Increasing the strength of the current , (ii) Having more turns in the coil, (iii) Increasing the area of the coil, (iv) By increasing the strength of the magnetic field.
What affects the speed of rotating field?
Speed is important to the rotating magnetic field of an AC motor. It is known as “synchronous speed.” This speed is calculated by dividing 120 times the frequency (F) by the number of poles (P) .
What are the factors that affect the rotation of the coil?
- increasing the size of the current;
- using a stronger magnet;
- increasing the number of turns of wire in the coil;
- reducing friction between the coil and the axel it rotates on.
How can we increase the speed of a DC motor?
Input Voltage: For a fixed load, the speed of the motor is affected by the applied voltage. Increase in voltage = increase in speed . Load Torque : For a fixed voltage, the speed of the motor is inversely affected by the load. Increase in load torque = decrease in speed.
What factors increase the speed of dc motor?
- The flux Φ
- The voltage across the armature.
- The applied voltage V.
What two factors change the speed of an AC induction motor?
The rotating field speed depends on the number of magnetic poles in the stator and is referred to as the synchronous speed. Frequency refers to the power supply frequency (e.g. 60 Hz). The number of magnetic poles (or simply poles) is the principal design factor affecting speed in AC motors.
What is the speed of a DC motor?
DC controls adjust speed by varying the voltage sent to the motor (this differs from AC motor controls which adjust the line frequency to the motor). Typical no load or synchronous speeds for an AC fractional horsepower motor are 1800 or 3600 rpm, and 1000-5000 rpm for DC fractional hp motors .
What controls the speed of a DC motor?
Thus, the speed of a DC motor can control in three ways: By varying the flux , and by varying the current through field winding. By varying the armature voltage, and the armature resistance. Through the supply voltage.
How do you increase motor speed?
The speed of the rotation of the electric motor can be increased by changing the resistance of the circuit , by decreasing the resistance of the electric motor, there is the increase of the current then the current strength will increase.
How do you change the speed of an electric motor?
AC motors are constant speed devices but their speed can vary if you change the input voltage or frequency or the windings that make the motor rotate. The most common and efficient way of changing the speed is to vary the frequency by using an inverter as the power supply .
How a rotating flux is developed?
The rotating magnetic field is produced radially around the rotor by the varying currents in the stator windings . The rotating magnetic field induces eddy currents in the squirrel cage's vertical bars causing it to rotate.
What device is used to ensure continuous rotation of the coil in the motor?
The Commutator
The answer is to use a commutator. This device prevents the wires from twisting. More importantly it actually allows the coil to keep rotating in one direction! The one shown is a split-ring commutator.
Can you make the coil spin in both directions?
Simply put, DC motors can turn in either direction (clockwise or counter-clockwise) and can be easily controlled by inverting the polarity of the applied voltage. Strictly speaking, the motors can actually create a force in either direction.
How do you increase the effect of a coil?
- Insert a soft Iron core or cylinder into coil – to concentrate the magnetic field lines.
- Increase the number of turns in the coil.
- Increase the current in the coil.
