Today’s automation industry quiz question comes from the ISA Certified Automation Professional certification program. ISA CAP certification provides a non-biased, third-party, objective assessment and confirmation of an automation professional’s skills. The CAP exam is focused on direction, definition, design, development/application, deployment, documentation, and support of systems, software, and equipment used in control systems, manufacturing information systems, systems integration, and operational consulting. Click this link for more information about the CAP program. The following question comes from the CAP study guide, Performance Domain IV, Development, software development and coding.
Which of the following statements correctly defines the relationship between the shaft speed of an AC squirrel cage motor, the frequency of the power input, and the number of poles for which the motor is wound, assuming negligible slip?
a) the shaft speed is directly proportional to the number of poles and does not depend on the motor frequency
b) the shaft speed is directly proportional to the frequency and does not depend on the number of poles
c) the shaft speed is directly proportional to the frequency and is inversely proportional to the number of poles
d) the shaft speed is inversely proportional to the frequency and is directly proportional to the number of poles
e) none of the above