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close this bookElectrical Machines - Basic Vocational Knowledge
close this folder4. Synchronous machines
close this folder4.4. Use of synchronous machines
View the document4.4.1. Synchronous generators
View the document4.4.2. Synchronous motors

4.4.2. Synchronous motors

Synchronous motors are used to drive pumps and compressors above all in the chemical industry and as drives for rotating tubular furnaces. There is also a combined application of bigger synchronous machines as motor and generator in pump storage plants. The synchronous machine is coupled to a water tube and a pump. Due to low network loads it operates as a motor and pumps water into a raised basin. During peak network load spells this water is able to run back into the lower basin by means of a turbine. The synchronous machine then operates as a generator.

Questions for repetition and control

1. Given a speed of n = 60 rpm, a synchronous generator shall generate an alternating voltage at a frequency of f = 50 Hz. How many pole pairs are required?

2. What is the operating frequency of a synchronous machine with two pole pairs where the rotor evidences a speed of 1500 rpm?

3. How can the voltage of a synchronous motor be changed?

4. Which conditions must be heeded for parallel switching of synchronous generators?