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Welcome to Classroom on demand, your source for educational materials related to the vertical transportation industry. This site represents the knowledge and expertise of the best engineers and mechanics in the elevator industry, and will help those new to the elevator industry learn about the basic workings of elevator systems, and also will serve as a reference for people with more experience.

Geared Machine

Traction = A traction elevator configuration uses ropes (cables) to raise and lower the car. The term “traction” is used because an adhesive friction develops between the rope and the traction machine’s drive sheave. As the drive sheave turns the rope is “pulled” across the drive sheave and the car is then either lifted or lowered depending on the direction the drive sheave is turning. This example shows the drive system of an overhead geared traction equipment type. (see file 1009-2) The overhead machine room contains the geared machine motor and drive sheave that coordinate to move the ropes, which raise and lower the car or the counterweight.
This application utilizes a drive sheave, motor, counterweight, and ropes, thereby eliminating the need for hydraulics. This application can be used for front openings as well as front and rear opening configurations.
The geared traction drive sheave has "V" shaped grooves, allowing it to grip (friction) the ropes. This creates traction and moves the car.
The gear box (part of the machine assembly) interfaces the electric motor with the drive sheave.
The geared machine, along with the related drive equipment, is generally located above the hoistway in a penthouse or overhead machine room. In some limited situations, it can be located next to the hoistway at a lower landing (basement machine room) or adjacent to the hoistway. Advantages
• There is no risk of oil contamination in the ground.
• This design offers almost unlimited travel.
• Geared traction car speeds are typically much faster than those of hydraulic applications. Geared traction cars can move at 500 (fpm) (2.5 m/s) or less.
• Better acceleration and deceleration rates than hydraulic, so better floor to floor performance times.
• A wide range of capacities are available: this design will accommodate low capacity passenger cars and high capacity freight cars.
• Because of the counterweight arrangement, power efficiency is greater than that of a hydraulic application.
• The geared traction equipment type is less expensive than the gearless traction type.
• Geared traction has a freight payload; the MRL equipment type has no freight payload.
Disadvantages
• The material cost and the installation time are substantially higher when compared to any of the hydraulic applications.
• There are structural building considerations, since all of the loading forces are hanging from the overhead.
• Elevator maintenance cost is generally higher (compared to hydraulic elevators).
• The time it takes to deliver and install the geared traction elevator after sending the purchase order is longer than for the hydraulic elevator type.
• Geared traction requires a larger machine room than the control room required by MRL traction equipment type.
• Geared traction has lower speeds than gearless traction equipment types

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