How to Determine Travel and Lifting Speeds part 2
The length of the runway, type of load carried and operator convenience are the important factors in speed selection. For floor operated cranes and runways up to 100′, one hundred fpm will usually be recommended. For runs over 200′, one hundred and thirty fpm may be more satisfactory. Cab operated crane speeds can range from 160 fpm to 350 fpm. The specific operating conditions will determine which speed is best. On two speed cranes and trolleys, slow speed is generally one-half the main speed. Multiple speed cranes generally have approximately equal speed steps.
Chain or Wire Rope Electronic Hoists:
Electric chain hoists are effective and efficient. They are available up to five tons capacity and larger. Wire rope hoists are available with an extensive variety of speeds and other options. In either type, both lift safely, and operate with similar ease and efficiency.
Wire rope hoists are more expensive because a wide grooved drum and larger housing to support the drum is required. Multiple and fast speeds or high production operations will usually require the selection of a wire rope hoist.
Chain type hoists are generally smaller and provide closer side clearances. They also permit a wider angle of pull than wire rope.
As a lifting medium, link chain is superior to wire rope. It is more flexible and much easier to inspect for wear or abuse. If it has been overloaded, it can be inspected for possible stretch and replaced before failure occurs. Wire rope can fray from the inside out and separate without warning. Link chain also gives a true vertical lift since it does not move from side to side as cable does. Generally, link chain will offer longer life than cable.
Electric link chain hoists are available up to 10 ton capacity in a limited selection of speeds.
Chains seldom require replacing while wire rope cables should be replaced periodically and are easily subjected to damage, crushing, fraying, weld burns, etc.