The driving force required to move the lift cab is provided by the lift motor. Of course, it should be noted that in tensile lifts, not all of the lifting force is provided by the engine; For example, when the elevator cab is at the lowest floor, the vanity box is high, and the elevator cab does not need to provide all the power needed to move the cabin. (Exactly like the function of a slave)
Types of elevator motors
If the input drive is from the electromotor to the pull pulley through a gear, the engine is gearbox-type.
Two-speed gearbox engine
In this case, a motor with two separate coils is used. At startup, the motor uses a high-speed coil and, in order to limit the current, a resistor is connected in series to them. Slow acceleration of the cab is achieved by gradually reducing the resistance field. Approaching the floor level, the high-speed motor or coil will fail and the motor will start with the low-speed coil. The speed of the cab decreases gradually until it reaches a short distance from the alignment, at which point the power cuts off and the brake automatically stops the cab.
Single Speed Gearbox (Variable Voltage and Frequency – VVVF)
The VVVF system has advantages that cannot be achieved with other systems. Very slow positive and negative acceleration make this system superior to the two-speed system. The system has a coil running on alternating current.
If the drive force is transmitted by direct connection from the motor to the pull pulley, the motor is of a gearless type. Gearless, voltage, and frequency motors work. This type of engine is very important for high-speed elevators. Today, this engine is the best choice for meeting high performance traffic conditions.
For slow acceleration, a regulator regulator is used in the stator field circuit to control the output of the stator. A variable resistance in the field circuit gradually decreases the resistance and increases the frequency of the stator rotation until the lift cab reaches its final acceleration with a slow acceleration. By creating the final speed, the stator frequency remains constant until the cab speed is reduced. An induction key set is used to slow down and stop the cab. The brakes only operate when the cab is stationary.