torque power and effeciency Flashcards
Prony brake
one device used to load a motor. has the ability to tell you how much load is applied to the motor
dynanometer
another type of motor that places a load on a motor and measures the amount of power that the motor can produce. used for more powerful applications
Mechanical advantage formula
MA= LE/LR
MA= effort force
LE= effort distance
LR= resistance distance
rotary mechanical power
rate or speed at which the rotating power transmission system turns the load.
torque is the rotating force produced by the motor
what is torque measured by?
foot-pound or newton-meter
what is rotary power measured by? what is the formula
horsepower
P=Ts x Ss
Ss= shaft speed(rpm
Ts = shaft torque(ft-ib or N-m)
P = rotary power(hp)
motor power- US customary
Po = T x S / 5252
motor power - SI metric
Po = t x s / 9549
US customary to SI metric formula
Po-SI = P o-us x .746
SI metric to US customary formula
Po-us = Po-si x 1.34
mechanical power efficiency formula
Em= (Po/Pi) x 100
Pi= input power
po = output power
Em = mechanical efficiency
what is an easy way to monitor the mechanical efficiency of the system
monitor the power drawn by the motor
what are the two method you can use to measure the load on a shaft
Current measurement- as motor torque increases, so does electrical current
torque transducer- device that is directly coupled to the shaft and generates an electrical signal that an ammeter or controller receives
