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 are the two factors influencing the speed of induction motor?
The speed of an AC motor depends on the frequency of the input power and the number of poles for which the motor is wound.
What factors determine the speed of a motor?
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 for determining the speed of a 3 phase induction motor?
1st factor is AC or DC, since DC is variable speed same as single phase motors. 2nd factor is number of poles of 3 phase stator windings. 3rd factor is frequency since with 3 phase motors 60 Hz means about 20 % more speed than 50 Hz. 4th factor is different frequencies of converters, e.g. of traction motors…
What is major factors that affect motor speed and torque?
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 are the 2 main types of losses in a motor?
There are two main kinds of losses in electric motors, which are often referred to as iron losses and copper losses. Dealing first with iron losses, these are made up of two ‘components’, namely eddy current losses and hysteresis losses.
How does an induction motor start?
A three-phase Induction Motor is Self Starting. When the supply is connected to the stator of a three-phase induction motor, a rotating magnetic field is produced, and the rotor begins rotating and the induction motor starts.
What are the 4 factors that speed up the simple DC motor?
There are 3 typical ways to control the speed of a DC motor:
- Flux Control. The speed of a dc motor is inversely proportional to the flux per pole. …
- Armature Control. When voltage and resistance are kept steady, the speed is directly proportional to the current. …
- Voltage Control.
What increases the speed of a motor rotation?
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. … Electric motors rotate at different speeds with different voltages.
What are the two factors controlling the speed of a DC motor?
Factors Affecting The Speed Of Dc Motor
- The applied voltage.
- The flux.
- The voltage across an armature.
What are the methods of speed control of induction motor?
Speed Control Methods of Induction Motor:
- Control From Stator Side:
- Control From Rotor Side:
- Speed Control by frequency variation:
- Speed Control By Pole Changing:
- Speed control by varying Supply voltage:
- Speed control by varying Rotor Resistance:
- Speed control by injected EMF:
- Speed control by Cascade Connection:
How do you calculate induction motor speed?
To calculate RPM for an AC induction motor, you multiply the frequency in Hertz (Hz) by 60 — for the number of seconds in a minute — by two for the negative and positive pulses in a cycle. You then divide by the number of poles the motor has: (Hz x 60 x 2) / number of poles = no-load RPM.
What is synchronous speed?
: a definite speed for an alternating-current machine that is dependent on the frequency of the supply circuit because the rotating member passes one pair of poles for each alternation of the alternating current.
How does current affect motor speed?
The current through the motor times the resistance of the motor creates a small voltage that must be subtracted from the applied voltage. As the load and current increase, this IR drop also increases causing the motor to lose a little speed.
What are the factors affecting torque?
Examples: Page 5 Torque is Determined by Three Factors: The magnitude of the applied force. The direction of the applied force. The location of the applied force.
How can we control DC motor in terms of speed and torque?
To control DC motors torque, a DC drive will regulate armature current. The armature voltage is unregulated allowing the motor to operate at whatever speed is necessary to achieve the set current /torque level.