mmet 301 Exam 1 Questions With Correct Answers

mmet 301 Exam 1 Questions With
Correct Answers

Electric Motor - CORRECT ANSWER✔✔-Current carrying conductor
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produces an electric field that may be attracted or repelled by another
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magnetic field |




Transforms electric power into rotary motion
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Unit system for north america - CORRECT ANSWER✔✔-NEMA - national
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electrical manufacturers association)
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Unit system for not north america - CORRECT ANSWER✔✔-SI -
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international standard (also known as IEC) | | | | |




Standards - CORRECT ANSWER✔✔-CEEMA- canadian electrical &
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electronic manufacturers alliance
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Typical frequency - CORRECT ANSWER✔✔-60 Hz
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Frame sizes (example - 145TC) - CORRECT ANSWER✔✔-Two digits
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Shaft center height in 16ths of an inch
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, Three digits|




First two digits indicate height in 4ths of an inch
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Third digit refers to mounting holes on motor base
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Letters
Know chart on page 228?
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Motor heating - CORRECT ANSWER✔✔-Raw polarity
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Causes of overheating: high/low voltage, slow or repeated starts, etc
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Loads - CORRECT ANSWER✔✔-Constant torque
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Variable torque |




Constant torque - CORRECT ANSWER✔✔-Increase in demand for
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horsepower proportional to speed increase | | | |




Variable torque - CORRECT ANSWER✔✔-Increase in demand for
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horsepower is greater than the increase in speed
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Motor insulation - CORRECT ANSWER✔✔-Windings are coated with
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insulation to prevent shorting to adjacent conductors or the motor
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frame
Temperature limits indicated by letter designation | | | | |