Facteur de marche = (temps de montée +temps de descente) / (temps de montée +temps de descente + temps d’arrêt)
Duty factor = (lifting time + lowering time) / (lifting time +idle time + lowering time + idle time)
http://www.cluma.com/pdf/verlinde/cat/productinfo kabeltakel...

Duty Cycle
In very general terms this refers to how long it takes for some action (or duty) to occur. It especially pertains to duties that are repetitive. In engineering terms it is a percentage that expresses the amount of actual working time as compared to the total operating time of an intermittently working piece of equipment. This could be a motor that has to do some operation periodically, or a hard drive, or a person. In electronics it is the ratio of the "on" to "off" period of a circuit or a pulse waveform. A periodic (repetitive) waveform may not spend equal amounts of time above and below zero and this ratio can loosely be referred to as duty cycle. More specifically it has to do with square or pulse type waveforms. A square wave has a duty cycle ratio of 1:1; meaning it spends equal time in both states (hi and low). Pulse waveforms, by definition, are not square and therefore are defined by their pulse width or duty cycle. Duty cycle is also called Duty FACTOR and Duty Ratio, and in this context is literally the product of the pulse duration and the pulse repetition frequency (Duration x Frequency = Pulse Ratio).
http://www.sweetwater.com/expert-center/glossary/t--DutyCycl...

Duty Factor: Ratio of the duration of time when a system is actually operating to the total time for a complete cycle of the system. e.g., if a tokamak experiment runs for 5 seconds and then sits for 500 seconds while the power supplies are recharged, then the duty factor is 1%. Similar to capacity factor for powerplants.
http://www.faqs.org/faqs/fusion-faq/glossary/d/


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Note added at 2 hrs (2007-11-15 11:54:09 GMT)
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Presumably in the case of your hoists, the motors are designed for intermittent operation for short periods at a time. Running them for longer might cause them to overheat and burn out, for example. Not that that is likely since presumably the height of the hoist relative to the lowest hook height will preclude running the motor longer than it takes to raise or lower an item to the full extent of the travel.