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2. Elevator Rated Motor Power

A 1 HP elevator motor cannot produce 1 HP for all weights of the rider. This is because a motor produces rated power only at or above its rated RPM. A typical motor is rated at 1750 RPM.

Assume the elevator gear ratio is optimized to give 660.3 ft. rise in 1 minute for a 50 lb. rider (See previous example). The gear ratio using a 1 foot diameter sheave will be:

Gear Ratio = Motor Rated RPM / Sheave RPM

Gear Ratio = 1750RPM / 210.3RPM

Gear Ratio = 8.3

Enter your weight to determine the sheave RPM which gives the elevator the rate of rise for 1 HP actual. At this sheave RPM, the Rated Power of a motor which will actually provide 1 HP toward lifting is: At this speed, and with a fixed gear ratio, the sheave and motor RPM must be:

Enter Your Weight: 
Height: ft m Sheave RPM:
    Required Motor Rating HP    kW
Actual Power = 1HP 0.746kW              
Actual Motor Speed      RPM

EASING EQUATIONS Open source under the BSD License. Copyright (c) 2001 Robert Penner JavaScript version copyright (C) 2006 by Philippe Maegerman All rights reserved.

By Clarence Klassen, KlassENgineering cklassen@klassen.on.ca