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Engineering and Application Data Service Factor Rated load is defined as the unit rating with a service factor of 1.0. Service factors are applied to provide a satisfactory life expectancy of the reducer. The service factor allows high horsepower and torque to be transmitted during short periods of operation. Normal starting or peak loads of 300% of input rated loads are permissible. This is within good practical standards and not considered an overload. Horsepower and output torque capacities shown in the ratings tables are calculated on 1.0 service factor for continuous 8-10 hour per day operation, uniform load, with electric motor drive. For applications conforming to a 1.0 service factory, the catalog ratings may be used directly. When selecting a reducer for other applications under different service conditions, multiply the actual input horsepower or output torque by the appropriate service factor (see table below) to obtain the equivalent value of horsepower and torque. These equivalent values may then be compared directly with the ratings in the tables. Where the unit selected has a higher rating than that actually required, the additional horsepower output will give the user a greater expected service life. Reducer Service Factors
Two-Pole Motors Under certain circumstances, users have been able to use 3600rpm motors, but this should be done with great care because it may exceed the thermal limits of the reducer. Such applications void our standard warranty. Self-Locking Features A worm gear is self-locking or non-reversible when the gear cannot drive the worm, This condition can occur when the lead angle of the worm is less than the friction angle. Generally there, are two cases where the self-locking feature may be applied:
However, vibrations from an outside source of the slightest start of the worm often upsets the static conditions of locked gearing enough to start motion. In addition, standard worm gears will not self-lock completely with single thread screws. This caracteristic and the other unpredictable factors mentioned above make it advisable to use a brake on the input shaft of the reducer rather than to rely on the self locking feature of the gearing. If compete self-locking is required, consult Cleveland Gear. Thermal Rating Current standards allow a maximum oil operating temperature rise of 140oF (60oC) above ambient, or a maximum operating surface temperature of 194oF (90oC) measured near the worm shaft bearing. Any temperature rise above these amounts will cause severe damage to seals, resulting in weat and reduced unit life. Because of sliding friction, worm gears run hotter than other types of speed reducers. The reducer housing may be too hot to touch under certain operating conditions. Suitable temperature measuring devices should be used to determine actual, oil operating temperatures if a problem is suspected. While the data in the Cleveland Gear rating tables are mechanical, field experience has shown that units can be expected to operate within thermal standards, providing that input horsepower limits stipulated and service factor adjustments described in this catalog are followed. For applications where loads are at design levels and operation is continuous, worm bottom style units will run cooler that worm top models, and are recommended. Lower operating temperatures will also result when synthetic oil is used. These oils provide better lubrication, improving efficiency and reducing thermal rise. Backlash All worm gears have an engineered minimum and maximum backlash. Backlash is measured as the rotational movement of the worm wheel at the pitch radius with the worm stationary. For backlash tolerances and methods of measuring. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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1-800-423-3169
Cleveland Gear Company 3249 East 80th Street Cleveland, Ohio 44104 sales@clevelandgear.com |