The classification of electromagnetic machinery

The author proposes to classify all dynamo electric machinery according to five sets of characteristics, as follows: 1. Type of field, as constant intensity, variable intensity, multiple polarity and homopolar. 2. Method of disposal of secondary power, which may be zero wattless, utilized in separate apparatus or transformed and returned to the line. 3. Use of commutators, which may be on either the primary or the secondary, or may be absent. 4. Method of magnetization, namely, high frequency magnetization as in the ordinary induction motor and low frequency magnetization as in synchronous and compensated motors. 5. Method of connection. Many types may be connected either in series or shunt. A tabulation of these characteristics is given, by reference to which any dynamo electric machine can be classified.