Projects:2020s1-2430 The Ball Bearing Motor Mystery - Revision history

A1705434: /* Experiment */

2020-10-19T03:43:20Z

‎Experiment

A1705434: /* Experiment */

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‎Experiment

A1705434: /* Experiment */

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‎Experiment

A1705434: /* Conclusion and discussion */

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‎Conclusion and discussion

A1705434: /* Results */

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‎Results

A1705434: /* Simulation */

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‎Simulation

A1705434: /* References */

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‎References

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‎References

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‎References

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‎References

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 '''Measuring equipment'''
-An Arduino Mega board along with code downloaded from the internet specifically written for measuring angular speed and torque was used to measure this motors characteristics.
+An Arduino Mega board along with code downloaded from the internet specifically written for measuring angular speed and torque was used to measure this motor's characteristics.
 To measure the angular speed of this motor, an encoder and photo interrupter are used. An encoder is simply a disc mounted on the motor shaft with some sections of it cut out or drilled out, so that light may pass through that section and the rest of the encoder will not pass light through. When the encoder is turning, it will periodically obstruct the photo interrupter. The photo interrupter will sense when it is being obstructed and send a signal to the Arduino board. The Arduino board uses this combination of the obstructed signals over a period of time to calculate angular speed.

@@ Line 69: / Line 69: @@
 '''Measuring equipment'''
-An Arduino mega board along with code downloaded from the internet specifically written for measuring angular speed and torque was used to measure this motors characteristics.
+An Arduino Mega board along with code downloaded from the internet specifically written for measuring angular speed and torque was used to measure this motors characteristics.
 To measure the angular speed of this motor, an encoder and photo interrupter are used. An encoder is simply a disc mounted on the motor shaft with some sections of it cut out or drilled out, so that light may pass through that section and the rest of the encoder will not pass light through. When the encoder is turning, it will periodically obstruct the photo interrupter. The photo interrupter will sense when it is being obstructed and send a signal to the Arduino board. The Arduino board uses this combination of the obstructed signals over a period of time to calculate angular speed.

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 To measure the torque, a prony brake and load cell are used. A prony brake is simply a clamp and arm. The clamp is mounted to the shaft tightly but not too tight as the shaft needs to be able to turn while the clamp and arm are stationary. The load cell is a steel bar and strain gauge which can detect forces applied to it. When the motor is turning, the prony brake will want to move from the friction of the motor shaft. The load cell is placed under the arm of the prony brake which apply a downwards force due to the friction from the turning shaft. The load cell signal is then amplified and sent to the Arduino board and calculates the torque. A potential problem with this method is that the ball bearing motor is known to only produce little torque and this setup may stall such a small motor, in which case the prony brake should be taken off and only angular speed is measured.
-[[File:2020s1 2430 Measuring equipment.png|thumb|center|Figure 7: Experiment setup]]
+[[File:LCD.jpg|thumb|center|Figure 7: Arduino Mega board and LCD screen]]
 '''Experiments'''
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 Another experiment has been designed the eliminates the bearings from the design and instead considers two conductive discs submerged in mercury in their place. Power is supplied to the discs through the mercury. If this motor works, it will allow for prolonged testing and may additionally disprove the thermal expansion theory. It should be noted that bearings are still used in this design but only the secure the motor in place.
-[[File:2020s1 2430 Liquid metal motor.png|thumb|center|Figure 8: Liquid metal motor design]]
+[[File:2020s1 2430 Liquid metal motor.png|thumb|center|Figure 9: Liquid metal motor design]]
 '''Power supply'''
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 A power supply 30V 20A power supply was used for this experiment. The ball bearing motor typically runs on a much larger current but due to its reduced size, this power supply was an appropriate choice.
-[[File:2020s1 2430 Power supply.png|thumb|center|Figure 9: Power supply used in experiment]]
+[[File:2020s1 2430 Power supply.png|thumb|center|Figure 10: Power supply used in experiment]]
 == Results ==

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 There are several theories as to why this small motor failed to operate.
-First is the ball bearings bulging and making the bearings ineffective. It is known the motor does not produce much torque and it may not be able to overcome the bearings bulging too much. This theory seems the most likely due to retarded rotation the motor experiences when a power supply is connected
+First is the ball bearings bulging and making the bearings ineffective. It is known the motor does not produce much torque and it may not be able to overcome the bearings bulging too much. This theory seems the most likely due to retarded rotation the motor experiences when a power supply is connected.
-Secondly is the quality control of the bearings. These bearings were bought online through eBay due to them being substantially cheaper than ball bearings of the same size from local bearing suppliers. However, it was noticed that these bearings were not identical to each other and some of them had a slightly larger inner diameter than others. Some bearings also were better at turning than others. For the experiments, bearings were compared to make sure similar sized and good turning bearings were chosen for the experiment but it is possible that due to poor quality, these bearings do not work. This may also be related to the first theory.
+Secondly is the quality control of the bearings. These bearings were bought online through eBay due to them being substantially cheaper than ball bearings of the same size from local bearing suppliers. However, it was noticed that these bearings were not identical to each other and some of them had a slightly larger inner diameter than others. Some bearings were also better at turning than others. For the experiments, bearings were compared to make sure similar sized and good turning bearings were chosen for the experiment but it is possible that due to poor quality, these bearings do not work well for the motor. This may also be related to the first theory.
-Thirdly is motor misalignment. A housing that the motor would sit in tightly and be secured down was built for the purpose of making sure the motor is aligned, however it is possible that the motor is still not perfectly aligned due to subtle bends in the fragile shaft and unequal balances on the encoder that are not noticed.
+Thirdly is motor misalignment. A housing that the motor would sit in tightly and be secured down was built for the purpose of making sure the motor is aligned, however it is possible that the motor is still not perfectly aligned due to subtle bends in the fragile shaft and unequal balances on the encoder that are not noticeable.
 Finally, whatever sustains rotation for this motor may not work when it is made this small. As the motor is still a mystery, it is hard to say if it could work when it is this small.

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 '''Practical'''
-This motor was operated from a range 0.5A to 3A, The motor was only increase to a max current of 3A because at this current the bearing shape deformed and became unusable likely due to immense heat generated in the bearing. Unfortunately this motor failed to sustain rotation on its own for these currents. Without a current applied, the motor shaft had good rotation but as soon as the power supply was connected and turned on, the motor became more difficult to turn. When the power supply was disconnected the shaft rotation would become better again.
+This motor was operated from a range 0.5A to 3A, The motor was only increase to a max current of 3A because at this current the bearing shape deformed and became unusable, likely due to immense heat generated in the bearing. Unfortunately this motor failed to sustain rotation on its own for these currents. Without a current applied, the motor shaft had good rotation but as soon as the power supply was connected and turned on, the motor became more difficult to turn. When the power supply was disconnected the shaft rotation would become better again.
 It was speculated that the reason for poor rotation was heating and expanding in the bearings making them difficult to turn. Therefore, the motor was tested in demineralised water which would help cool the bearings. However, the motor still failed to turn and would become more difficult to turn when the power supply was connected.

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 == Simulation ==
-A simple version of the motor was created in the simulation software COMSOL. The purpose is to simulate the motor in a virtual environment where the motor can be tested without being subjected to bearing deterioration that affects accuracy of the results. The simple version eliminates bearings from the design and instead considers two conductive discs in their place.
+A simple version of the motor was created in the simulation software COMSOL as the regular ball bearing motor is too complex to simulate. The purpose is to simulate the motor in a virtual environment where the motor can be tested without being subjected to bearing deterioration that affects accuracy of the results. The simple version eliminates bearings from the design and instead considers two conductive discs in their place.
 [[File:COMSOL.png|thumb|center|Figure 5: Motor in COMSOL with red arrows indicating path of current]]

← Older revision		Revision as of 03:15, 19 October 2020
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	[2] Choo, J.L Soong, W.L, Abbott, D. "Toward Characterization of Huber's Ball-Bearing Motor" Proceedings of SPIE, no. 5649 (2005): 700-720		[2] Choo, J.L Soong, W.L, Abbott, D. "Toward Characterization of Huber's Ball-Bearing Motor" Proceedings of SPIE, no. 5649 (2005): 700-720
−
−	~~'''Other useful references'''~~

	[3] Thompson, B. Shen, Y. Tay, K. Soong, W.L. Davis, B.R. Abbott, D. "Investigation of the Huber effect and its application to micromotors" Proceedings of SPIE Electronics and Structures for MEMS, no. 3891 (1999): 178-183		[3] Thompson, B. Shen, Y. Tay, K. Soong, W.L. Davis, B.R. Abbott, D. "Investigation of the Huber effect and its application to micromotors" Proceedings of SPIE Electronics and Structures for MEMS, no. 3891 (1999): 178-183

← Older revision		Revision as of 03:15, 19 October 2020
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	[4] Lauterbach, A.P. Soong, W.L. Abbott, D. "Investigtion of small motors operating under the Huber effect" Proceedings of SPIE, no. 4236 (2001): 306-318		[4] Lauterbach, A.P. Soong, W.L. Abbott, D. "Investigtion of small motors operating under the Huber effect" Proceedings of SPIE, no. 4236 (2001): 306-318

−	[5] Hayward, J. Saing, R. "The ball bearing motor mystery 2019" The University of Adelaide, November 29 2019, Accessed on: March 17 2020. [Online]. Available: https://projectswiki.eleceng.adelaide.edu.au/projects/index.php/Projects:2019s1- 142_The_Ball_Bearing_Motor_Mystery	+	[5] Hayward, J. Saing, R. "The ball bearing motor mystery 2019" The University of Adelaide, November 29 2019, Accessed on: March 17 2020. [Online]. Available: https://projectswiki.eleceng.adelaide.edu.au/projects/index.php/Projects:2019s1-142_The_Ball_Bearing_Motor_Mystery

@@ Line 139: / Line 139: @@
 == References ==
-[1] H. Gruenberg et al, "The ball bearing as a motor," Am. J. Physics, 46, pp. 1213-1219, 1973.
+[1] Gruenberg, H. "The ball bearing as a motor" American Journal of Physics, no. 46 (1978): 1213-1219.
-[2] Joo L. Choo, Wen L. Soong and D. Abbott，“Toward Characterization of Huber’s Ball-Bearing Motor”，Smart Structures, Devices, and Systems II, edited by Said F. Al-Sarawi, Proceedings of SPIE Vol. 5649 (SPIE, Bellingham, WA, 2005), [Online]. Available: http://proceedings.spiedigitallibrary.org/. .
+[2] Choo, J.L Soong, W.L, Abbott, D. "Toward Characterization of Huber's Ball-Bearing Motor" Proceedings of SPIE, no. 5649 (2005): 700-720
 '''Other useful references'''
-[3] Y. Shen, B. K. Tay, B. Thompson, W. L. Soong, B. R. Davis, D. Abbott, “Investigation of the Huber effect and its application to micromotors”, Part of the SPIE Conference on Electronics and Structures for MEMS Royal Pines Resort, Queensland, Australia • October 1999, [Online]. Available:  http://spiedigitallibrary.org/.
+[3] Thompson, B. Shen, Y. Tay, K. Soong, W.L. Davis, B.R. Abbott, D. "Investigation of the Huber effect and its application to micromotors" Proceedings of SPIE Electronics and Structures for MEMS, no. 3891 (1999): 178-183

← Older revision		Revision as of 03:12, 19 October 2020
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	[2] Joo L. Choo, Wen L. Soong and D. Abbott，“Toward Characterization of Huber’s Ball-Bearing Motor”，Smart Structures, Devices, and Systems II, edited by Said F. Al-Sarawi, Proceedings of SPIE Vol. 5649 (SPIE, Bellingham, WA, 2005), [Online]. Available: http://proceedings.spiedigitallibrary.org/. .		[2] Joo L. Choo, Wen L. Soong and D. Abbott，“Toward Characterization of Huber’s Ball-Bearing Motor”，Smart Structures, Devices, and Systems II, edited by Said F. Al-Sarawi, Proceedings of SPIE Vol. 5649 (SPIE, Bellingham, WA, 2005), [Online]. Available: http://proceedings.spiedigitallibrary.org/. .
		+
		+	'''Other useful references'''

	[3] Y. Shen, B. K. Tay, B. Thompson, W. L. Soong, B. R. Davis, D. Abbott, “Investigation of the Huber effect and its application to micromotors”, Part of the SPIE Conference on Electronics and Structures for MEMS Royal Pines Resort, Queensland, Australia • October 1999, [Online]. Available: http://spiedigitallibrary.org/.		[3] Y. Shen, B. K. Tay, B. Thompson, W. L. Soong, B. R. Davis, D. Abbott, “Investigation of the Huber effect and its application to micromotors”, Part of the SPIE Conference on Electronics and Structures for MEMS Royal Pines Resort, Queensland, Australia • October 1999, [Online]. Available: http://spiedigitallibrary.org/.