There are three common gearing systemsused in winches, the worm gear, spur gear and planetary gear. The main job of these gears is all the same; to gear down the high speed motor to a low speed, high torque winch drum. The gear reduction ration is determined by how much the motor's output revolutions are reduced for the spindle. If the reduction is great enough the motor will have to work less and will be more efficient.
The difference in the gearing systems has more to do with their transfer efficiency.
A worm gear has a transfer efficiency of 35-40 percent. This will cause the winch to self brake even when under a heavy load, but will require the unit to have a clutch mechanism for free spooling. The worm gear offers the most reduction, is very reliable with build in braking mechanism and a generally slower winching speed.
The spur and planetary gear systems have efficiencies of 75 and 65 percent respectively. What this can mean is that they have a tendency to free spool when loaded making a braking mechanism necessary. The planetary gears are more commonly used and provide strength and smooth operation as well as good resistence to torque loads. Only the WARN M8274 has a spur gear due to its different design characteristics.
THE SPECIALIST OF WINCH
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