Elenco Snaptricity&reg - Manual (Page 44)

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3-Speed Motor Project #34
Snappy says:
This is one way to
control the speed
of a motor.
Educational Corner:
Place the fan on the motor. Set both slide
switches to position B and push the press
switch. The motor will not spin.
Now set the slide switches to position C, push
S2 to get the motor spinning, then set the slide
switches back to B. The motor could not start
spinning with the other lamps on, but it will
keep spinning as long as you keep pushing
S2. Why?
The surfaces touched by the motor shaft offer
some resistance to motion, called friction.
Once the initial friction is overcome, it doesn’t
take much effort to keep the motor spinning.
Motor performance may vary, in rare cases it
may spin in all switch settings.
Electric Paths
Do you want to learn more?
1A
Friction
1A
+
Push the press switch (S2) to turn on the motor and use
the slide switches (S5) to control its speed. The meter (M5)
measures the current. You may need to give the motor a
push to get it started, but do not touch it while it is spinning.
Operation
Here you control the motor speed by diverting some of the
current to the lamps.
Description
Build the circuit. Set the meter (M5) to the 1A scale and
leave the fan off the motor (M1).
Assembly
+
!
WARNING: Moving parts. Do not touch
the fan or motor during operation.