Technology & Education: Energy efficiency of lifts - Part 3

摘要

Counterbalcmcing ratio and variable speed drives. Continuing the series on energy efficiency of lifts. Part 1 was published in 5/05 (pg, 66) and part 2 was published in 6/05 (pg. 79). The drive motor of a traction lift is required to move thepayload of passengers in the car. In order to reduce the size of the drive motor, the weight of the car plus a proportion of the maximum weight of the passengers (the rated load) is balanced by a counterweight. The commonly used value for the counterbalancing ratio is 50%. This means that when the lift is half full with passengers, the motor only needs to overcome various losses in order to move the lift.