Cable Safety Factor
Depending on the classification group of the mechanism, the exact rope safety factor (breaking strength) for lifting winches can be chosen according to ISO 16625-2013. A five-fold factor is normally applied to lifting applications; threefold for pulling winches and an eight to ten-fold factor for personnel lifting.
We generally use either friction or claw-type clutches, dependent on the requirement. Friction clutches can be operated under load, can compensate for differences in turning speeds between the drum and driveline and can be operated either manually or remotely. As such, they tend to be more complex and expensive than claw-type clutches which, by contrast, are simpler, more robust, dependable and inexpensive.
Ordinarily, we work with protection class IP 54 (splash watertight and dust-proof) for motors and control boxes. Pendant remote controls are IP 65 protected. Motors can also be supplied with IP 56 TENV (totally enclosed and non-ventilated), for deck equipment in marine use. We provide explosion-proof winches and spark-free motors and control boxes for use in designated zones.
The distance between the drum and the sheave can be 20 times the length of a smooth drum and 15 times the length of a grooved drum. For large fleet angles, a cable spooling gear may be required. A grooved winch drum helps the cable spool correctly onto the drum, but so too does the application of a constant load, so pressure rollers are recommended to avoid slack in the cable.