PASCO SE-8658A PERMANENT MAGNET MOTOR - Manual (Page 9)

5
012-07210A Permanent Magnet Motor
Operation as a DC motor
The Permanent Magnet Motor can be used to
demonstrate the operation of a DC motor ( Experiment
1). Students can explore relationships between motor
speed and voltage, as well as between direction of
armature rotation and polarity, learning key concepts
including: action of the split ring commutator,
dependence of speed on voltage, dependence of
direction of rotation on polarity, right-hand rule, and
direction of current flow from positive to negative.
Action of AC and DC generators
Spinning the armature by hand while it is connected to
a sensitive DC meter or to the Signal Interface II shows
the action of an AC generator, as well as the rectifying
action of the commutator in a DC generator
(Experiment 2).
Suggested Uses
Operation of a synchronous AC motor
Coupled with an AC signal supplied by the PASCO
PI-9587C Digital Function Generator/Amplifier,
Science Workshop 700 or 750 Interface and CI-6552A
Power Amplifier, or a similar function generator, the
Permanent Magnet Motor will operate in sync with 15
to 30 Hz (and often wider range) signals (Experiment
3). Students can explore the relationship between AC
voltage and motor speed, as well as between AC
current frequency and motor speed. They can conduct
detailed explorations of the precision of synchronism
of AC current and motor speed with a PASCO SF-9211
Digital Stroboscope or PASCO ME-9215A Digital
Photogate Timer with memory or by observing the
stroboscopic effect of an ordinary fluorescent lamp at
selected motor speeds. As a result, they learn key
concepts, including the independence of AC motor
speed and voltage, dependence of AC motor speed on
current frequency, and action of a dual slip-ring
commutator.
Additional possibilities
The Permanent Magnet Motor can be used to
determine the speeds of maximum power and
maximum efficiency of a DC motor by varying the load
while simultaneously measuring the speed, torque, and
armature current. In this experiment, you can measure
the motor’s speed with a photogate or stroboscope.