| Voltage(V): | 240V | Frequency(Hz): | 50/60Hz |
| Input power(W): | 50W | Rated speed(RPM): | 1200RPM |
Outer dimensions
Operation status of induction motor
The induction motor uses the principle of electromagnetic induction to generate a rotating magnetic field through the three-phase current of the stator, and interacts with the induced current in the rotor winding to generate electromagnetic torque for energy conversion. Under normal circumstances, the rotor speed of an induction motor is always slightly lower or slightly higher than the speed of the rotating magnetic field (synchronous speed), so an induction motor is also known as an "asynchronous motor".
When the load of an induction motor changes, the speed and slip of the rotor will change accordingly, causing corresponding changes in the electromotive force, current, and electromagnetic torque in the rotor conductor to meet the needs of the load. According to the sum of the positive and negative slip rates, induction motors have three operating states: electric motor, generator, and electromagnetic braking.
When the rotor speed is lower than the speed of the rotating magnetic field (ns>n>0), the slip rate is 0<s<l. Set the air gap rotating magnetic field generated by the sub three-phase current to turn counterclockwise, and follow the Right-hand rule to determine the direction of the induced electromotive force after the rotor conductor "cuts" the air gap magnetic field. Due to the short circuit in the rotor winding, there is current flowing through the rotor conductor. The interaction between rotor induced current and air gap magnetic field will generate electromagnetic force and torque; According to the left hand rule, the direction of electromagnetic torque is the same as the direction of rotor rotation, that is, electromagnetic torque is a driving torque. At this time, the motor inputs power from the power grid, and through electromagnetic induction, the rotor outputs mechanical power. The motor is in the motor state.
If the motor is driven by a prime mover and the rotor speed is higher than the rotating magnetic field speed (n>ns), then the slip rate s<0. At this point, the induced electromotive force and the active component of the current in the rotor conductor will be opposite to the state of the motor, so the direction of the electromagnetic torque will be opposite to the direction of the rotating magnetic field and rotor rotation, that is, the electromagnetic torque is a braking torque. In order for the rotor to continuously rotate at a speed higher than the rotating magnetic field, the driving torque of the prime mover must overcome the electromagnetic torque of the braking; At this point, the rotor inputs mechanical power from the prime mover and outputs electrical power through electromagnetic induction. The motor is in a generator state.
If the rotor rotates against the direction of the rotating magnetic field (n<0) due to mechanical or other external factors, the slip rate s>1. At this point, the relative velocity direction of the air gap magnetic field "cut" by the rotor conductor is the same as that of the motor state, so the active components of the induced electromotive force and current in the rotor conductor are in the same direction as the motor state, and the direction of the electromagnetic torque is also the same. However, due to changes in rotor rotation, this electromagnetic torque is manifested as braking torque for the rotor. At this point, the motor is in an electromagnetic braking state. On the one hand, it inputs mechanical power from the outside, while also absorbing electrical power from the power grid, both of which become internal losses of the motor.
