Mechatronics Learning Studio
Power DynoTorque
Maxime Lepage, Samuel
Leblanc-Robert, Marc Myre, Dept of Mechanical Engineering,
University of Ottawa
Safety instructions
In general
1)
Read these instructions
2)
Keep these instructions
3)
Beware of all warning
4)
Follow all instructions
5)
Do not use apparatus near water
6)
To reduce the risk of electric shock, do not
expose this apparatus to rain or moisture
Concerning the power supply
1)
The power supply unit can be operated in an
ambient temperature from 5oC up to 40oC
max
2)
Do not give too much power to a small resistance. A small
resistance receiving
too much power can overheat and cause minor
burns.
3)
Do not simultaneously touch the positive and the
negative terminal of the power supply. This can cause an
electric shock.
Concerning the Laser
1)
Always keep in mind that a misuse laser can be
dangerous
2)
Do not point a laser into eyes.
Components
Material Needed for the Experiment
?
12 V DC motor
?
Photo-electric cell
?
10 kΩ
resistor
?
9 V battery
?
Coupler
?
Mounting base for the motors
?
Spring with a known constant
?
Frequency counter
?
Multimeters
?
Ohm ranger
?
Power supply
?
Breadboard
?
Various wires
?
Tape
Connection of the Multimeters and the Frenquency
Counter
V: voltmeter
A: ammeter
1.
Calculate the input voltage and current and the
output voltage and current.
2.
Measure the frequency through the Photocell.
Calculate the Frequency (rpm) of the Motor
1. Once the ammeters, voltmeters and frequency
counter are connected properly, you have to connect the 9V
battery to the circuit.
2. Connect the power supply to the motor.
3. Use the black coupler to couple the generator
to the motor you want to evaluate.
4. Turn the ammeters, voltmeters, the frequency
counter, the power supply and the laser ON.
5. Provide the circuit with approximately 10V and
300 mA.
6. Use the Ohm Ranger to do at least 5 tests
using 5 different resistors.
7. Write down the data which are Vin,
Ain,
Vout,
Aout,
Resistance and the Frequency for every tests.
Note: The frequency will be given in Hz by the
frequency counter. Use this formula to convert it in RPM
X Hz * 60 (secondes/min) * 2π
(rad/ rotation) = Y RPM
Calculate the Torque of the Motor (with a Spring)
1.
Once you have calculated the frequency, leave
only the ammeter that displays the input current.
2.
Separate the generator from the motor you are
testing.
3.
Attach the non-elastic wire to the shaft.
4.
Do 5 tests with 5 different input currents
(constant input voltage) and write down the elongation of the
spring for all 5 tests.
(Do not set up Vin to high!)
Troubleshooting
Problem |
Action |
Page |
The photocell circuit is not responding |
-
Test the 9V battery with a multimeter.
®If
less than 3v are measured, change the battery for a
new one. |
|
The frequency counter displays
inconsistent values |
-
Verify the connection of the photocell
circuit.
-
Make sure that there is no change in
ambient light during the test. |
|
The motor is not working |
-
Test the motor with another power supply.
-
Buy a new motor ( The one used may have
overheated) |
|
Smoke is coming from the resistance |
-
Lowering the power supply of the motor or
use a larger resistance |
|
Inconsistent values at the output of the
generator |
-
Use single resistance instead of the
OhmRanger |
|
The movement of the spring is jerky when
testing the
torque
|
-
Use a spring with a smaller constant of
elasticity |
|