Cumulative Compound DC Motors are used for Elevators or Lifts because it has Variable Speed, Adjustable varying speed and High starting torque. The latest elevator or lifts designs use 3-phase induction motors with variable frequency drive electronic controls.
Which type of DC motor is used in lift?
The latest lift designs use 3-phase induction motors with variable frequency drive electronic controls. Some may also use a similar system with permanent magnet (brush less) DC motors. DC shunt motors.
Which motor is used in passenger lift?
Conventionally, there are, in general, three types of motors used in elevator systems: AC, DC and a hybrid between the two. The AC-2 motor is a primitive motor drive popular at least half a century ago for low-speed elevators. It is usually coupled with a worm gear to reduce speed and increase driving torque.
How does a DC motor work in an elevator?
For high-speed elevators, however, DC motors were used. This is because DC motors usually have higher starting torque than AC motors. A cross-section of the DC motor is shown in Figure 3. DC passes through respective field windings on the stator poles to produce a magnetic flux around the pole, Φf.
What is a DC series motor?
Series DC motors are a group of self-excited DC motors in which the field coil is connected in series to the armature winding and thus a higher current passes through it. A series DC motor mission is to turn the electrical energy into mechanical one based on electromagnetic law.
Are elevators AC or DC?
Geared traction machines are driven by AC or DC electric motors. Geared machines use worm gears to control mechanical movement of elevator cars by “rolling” steel hoist ropes over a drive sheave which is attached to a gearbox driven by a high speed motor.
What is back emf in DC motor?
When the armature of the DC motor rotates under the influence of driving torque, the armature of the conductors moves through a magnetic field inducing an emf in them. The induced emf is in the opposite direction to the applied voltage and is known as the back emf.
What is starting resistance of DC motor?
In practical DC machines, armature resistance is basically very low, generally about 0.5 Ω. Therefore, a large current flows through the armature during starting.
Where is the lift motor?
This is often on a rooftop of a building or two storeys above the highest storey that the lift serves. The room can also be found on the ground floor or in the basement if overhead space is unavailable.