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Insulation system. The electrical insulation system for wires used in generators, electric motors, transformers, and other wire-wound electrical components is divided into different classes by temperature and temperature rise. The electrical insulation system is sometimes referred to as insulation class or thermal classification.
Class 150 Rating This is the rating required to protect microfilm, microfiche, and other film-based information storage media. Above 150 °F (65.5 °C) film is distorted by the heat and information is lost. A Class 150-2 Hour vault must keep the temperature below 150 °F. for at least two hours, with temperatures up to 2,000 °F. (1,093.3 °C) outside the vault.
The above table shows that the surface temperature of a piece of electrical equipment with a temperature classification of T3 will not rise above 200 °C. The surface of a high pressure steam pipe may be above the autoignition temperature of some fuel-air mixtures.
Fire/smoke dampers are similar to fire dampers in fire resistance rating, and also prevent the spread of smoke inside the ducts. When a rise in temperature occurs, the fire damper closes, usually activated by a thermal element which melts at temperatures higher than ambient but low enough to indicate the presence of a fire, allowing springs to ...
IEC 60269 unifies the electrical characteristics of fuses that are dimensionally interchangeable with fuses built to earlier British, German, French or Italian standards. [2] The standard identifies application categories which classify the time-current characteristic of each type of fuse. The application category is a two-digit code.
Motor velocity constant, back EMF constant. is the motor velocity, or motor speed, [2] constant (not to be confused with kV, the symbol for kilovolt ), measured in revolutions per minute (RPM) per volt or radians per volt second, rad/V·s: [3] The rating of a brushless motor is the ratio of the motor's unloaded rotational speed (measured in RPM ...
An operating temperature is the allowable temperature range of the local ambient environment at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the ...
The ampacity of a conductor depends on its ability to dissipate heat without damage to the conductor or its insulation. This is a function of the insulation temperature rating, the electrical resistance of the conductor material, the ambient temperature, and the ability of the insulated conductor to dissipate heat to the surroundings.