- Domeniu: Electrical equipment
- Number of terms: 4774
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Localized currents induced in an iron core by alternating magnetic flux. These currents translate into losses (heat) and their minimization is an important factor in lamination design.
Industry:Electrical equipment
The space between the rotating (rotor) and stationary (stator) member in an electric motor.
Industry:Electrical equipment
The efficiency of a motor is the ratio of mechanical output to electrical input. It represents the effectiveness with which the motor converts electrical energy into mechanical energy. NEMA has set up codes which correlate to specific nominal efficiencies. A decrease in losses (the elements keeping the motor from being 100% efficient of 10% constitutes an upward improvement of the motor of one code on the NEMA table. Each nominal efficiency has a corresponding minimum efficiency number.
Industry:Electrical equipment
Used on motors with blowers to measure the difference in pressure across the filter so as to detect a clogged filter.
Industry:Electrical equipment
A unit of measurement of time as applied to alternating current. One complete cycle =360 electrical degrees. One cycle in a rotating electric machine is accomplished when the rotating field moves from one pole to the next pole of the same polarity. There are 360 electrical degrees in this time period. Therefore, in a two pole machine there are 360 degrees in one revolution, and the electrical and mechanical degrees are equal. In a machine with more than two poles, the number of electrical degrees per revolution is obtained by multiplying the number of pairs of poles by 360.
Industry:Electrical equipment
A device used in air hooded motors to detect the temperature of the exhausted air. When used in this manner an air temperature switch will detect blockage in the cooling air system or long-term motor overload.
Industry:Electrical equipment
The ratio of electrical inductance to armature resistance. Electrical time constant in seconds defined as Electrical where La is the armature circuit inductance in henries and la is the rated full load armature current.
Industry:Electrical equipment
The atmospheric altitude (height above sea level) at which the motor will be operating; NEMA standards call for an altitude not exceeding 3,300 ft. (1,000 meters). As the altitude increases above 3,300 ft. and the air density decreases, the air stability to cool the motor decreases - for higher altitudes higher grades of insulation or a motor derating are required. DC motors require special brushes for high altitudes.
Industry:Electrical equipment
The temperature of the surrounding cooling medium, such as gas or liquid, which comes into contact with the heated parts of the motor. The cooling medium is usually the air surrounding the motor. The standard NEMA rating for ambient temperature is not to exceed 40fC.
Industry:Electrical equipment
A synonym for voltage, usually restricted to generated voltage.
Industry:Electrical equipment
