ATT TECHNICAL ASSESSMENT TEST 2 COMPLETE PREPARATION GUIDE AND CORE SKILLS REVIEW

ATT TECHNICAL ASSESSMENT TEST 2
COMPLETE PREPARATION GUIDE AND CORE
SKILLS REVIEW

◉ What are the characteristics of motors and generators?
Answer: speed, torque, counter electromotive force (CEMF), load,
power, and efficiency


◉ What is speed?
Answer: the rotation of the shaft


◉ What is speed measured in?
Answer: rpm or rps


◉ What is torque?
Answer: the twisting force that causes the shaft to rotate


◉ What is torque measured in?
Answer: ft - lbs


◉ What is counter electromotive force (CEMF)?

,Answer: the rotation of a motor's shaft and opposes the applied
voltage


◉ What is a load?
Answer: received the output of a motor or a generator


◉ What is power?
Answer: the rate at which work is done


◉ Formula for power:
Answer: P = torque x rpm x K


◉ What is power measured in?
Answer: horsepower or ft - lb/s


◉ Formula for power efficiency:
Answer: watts = ft - lb/s x 1.356


◉ What is efficiency?
Answer: a rating of how well a motor or generator changes power


◉ Formula for efficiency:

, Answer: Pout/Pin x 100


◉ If a generator's input rpm increases, the output voltage
_______________
Answer: increases


◉ As a motor's input voltage decreases, the output rpm ______________
Answer: decreases


◉ In a motor, if rpm decreases, CEMF ________________
Answer: decreases


◉ In a motor, if CEMF decreases, the torque ______________
Answer: increases


◉ In a motor or generator, torque x rpm x K gives you
____________________
Answer: mechanical power


◉ What does a basic motor consist of?
Answer: two magnets and a current carrying conductor