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Torque Speed Characteristics
This is the torque-speed curve of a typical 3 speeds AC PSC induction
motor and a matching load curve (in blue). MEA's Motor Testing System
produces these curves within a few seconds (including set up) without
using any mechanical or inertial load.
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click on picture to enlarge
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Torque Current Characteristics
These are the torque-current and torque-speed curves of a typical
permanent magnet DC motor. Once again, MEA's Motor Testing System
produces these curves without using any mechanical or inertial load, and
within only a few seconds, including set up.
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click on picture to enlarge
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Current Speed Characteristics
This graph shows the current-speed curve of a Universal AC Commutator
Motor. MEA's Motor Testing System produces this data from the entire
speed range of the motor, without using any mechanical or inertial load,
and in mere seconds.
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click on picture to enlarge
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Speed spectrum characteristics
The speed spectrum characteristics reveal important
information regarding the motor's performance. The
graph shows the speed spectrum of a PSC motor. The two peaks in the graph
indicate speed variations, at two main frequencies:
• The
25Hz component indicates minor imbalances in this particular motor.
• The 100Hz component is typical for AC PSC Induction motors. The
amplitude of•this component
determines the motor's noise and vibrations.
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click on picture to enlarge
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Combined chart
This is a combined chart showing all the important characteristics of a
typical AC PSC motor: Torque-speed, current speed, power in, power out
and efficiency
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click on picture to enlarge
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Torque-Speed Oscillations characteristics
During steady state, the PSC motor speed varies periodically around the
so-called
constant speed. These variations result from the changing torque of the
rotating magnetic field. Quieter and smoother running motors have smaller
ripple. MEA's Motor Testing Systems are capable of measuring the varying
torque and speed of the motor.
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The graph, obtained
from a typical PSC motor, shows the changes in torque versus speed of a
free running motor. As you can see, the speed changes within a 50 RPM
range, and the torque changes
between -110 OzIn and +130 OzIn.
Motor designers normally seek to minimize
variations in speed and torque.
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click on picture to enlarge
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The dynamic
torque-speed characteristics provide a measure of the motor's shaft
vibrations and of the magnetic noise magnitude, common attributes of AC PSC
motors.
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