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Forum Index : Other Stuff : F&P BLDC MOTOR / GENERATOR PROJECT
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duffman25 Newbie  Joined: 21/11/2011 Location: AustraliaPosts: 4 |
Hi everyone im new to all this but find electronics and mechanical things very interesting and need help building my project! The project consists of using the F&P Smart Drive Motor and parts as I work in an electrical retailer and have many dead machines coming in for me to scrap! I want to have 4 smart drives all joined on the one shaft, 2 being used as alternators 1 used as BLDC Motor and one to generate electricity for whatever you like! Looks like this (very rough) – ----[]----[]----[]----[]---- What I need to know is why when I join all 3 phases together (leads) coming out of the smart drive it’s nearly impossible to turn? What configuration will I need to rewire the alternators and BLDC motor? Will 2 smart drive alternators make enough power to run the BLDC motor? How can I build a controller for the BLDC motor? Would de-cogging the stators help to reduce friction and thus make it easer for my unit to operate? Any input would be greatly appreciated!!! Cheers, Rohin |
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| duffman25 Newbie Joined: 21/11/2011 Location: AustraliaPosts: 4 |
Well i've worked out to convert the AC current from the 2 F&P alternators I will need 3 bridge rectifiers. Would 3 400V 35A Bridge rectifiers be enough? I've worked out a way to mount the units inline, will build soon and put picss up :) |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Rohin What are you trying to achieve here? It looks like you want to use a combination of motors and alternators to drive eachother, and then tap off some power. Is that the aim? If so, what you are trying to do cant work, but its a common idea so dont feel bad. Every step in the cycle looses power. Assume every alternator and motor is 80% efficient, a good average. If you kicked this thing off with say 100 watts of electrical power, the motor will put out 80watts of shaft power. The two alternators then have 40 watts each fed into them, but only put out about 32 watts each, so you now have 64 watts of electrical power to feed back into your motor. The moter needs 100 watts. The whole device very quickly grinds to a halt. Even if the motors and alternators were 100% efficient ( which is not possible ), air resistance and bearing losses would also bring the device to a halt. I know there are so called plans and patents to say this sort of device works, but they are fake, drawn up by con artists trying to take you money. You always need to put energy in to get energy out. The F&P's make good wind turbines or hydro power plants. There is a market for good F&P motors, dont throw them out whatever you do. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| duffman25 Newbie Joined: 21/11/2011 Location: AustraliaPosts: 4 |
Yes exactly, trying to get 2 or more of these alternators to provide enough power to run the one as a brushless motor driving the alternators all on the same shaft. so if say the bldc motor needs 100watts of power to spin, then both (or more) alternators need to be providing more than 50watts each as there will be losses in both mechanical and electrical things? Could i rewire the alternators so they make less volts and more amps to power the bldc motor Really sucks if this dosnt work then I will make a windmill with 2 F&P alternators on it! Thanks for the input! Much appreciated Rohin |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Rohin If you rewire the alternators to make more current, then you need to put more shaft power into them to get the extra power out. So you need a feed more power into the motor to drive the alternators. Unfortunately any amount of re-wiring, electronics or addition magnets wont make it work, its governed by the laws of thermodynamics http://en.wikipedia.org/wiki/Laws_of_thermodynamics. Its just like you cant make a clock that winds its own spring using the energy stored in the spring. Or simpler, if you stand in a bucket and pull up on the handle, you wont lift yourself off the ground. But like I said, its a common idea, so dont feel bad. Once you understand why it cant work, it makes sense. There have been a few dual stator F&P based windmills on this forum, they work well and you can expect up to 600 watts in good wind conditions. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| desert_rain Newbie Joined: 30/12/2011 Location: PakistanPosts: 8 |
What I have understood out of my experience is that energy can be converted from one form to the other at the cost of some losses (nothing in the world can be 100% efficient). Energy conversion in two ways in your case that either from mechanical energy to elecrical by an alternator or from electrical to mechnical energy using a BLDC motor. Naeem |
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| duffman25 Newbie Joined: 21/11/2011 Location: AustraliaPosts: 4 |
Another idea could be to build my project but supplement some extra power from a solar panel? therefore the unit will spin and make power.... I THINK haha I've been very busy lately, my computer died so I built a new one consisting of core i5 n Z68 motherboard :) Will try to build this still, just trying to get around the engineering kind of things. |
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| Florin Newbie Joined: 28/04/2009 Location: RomaniaPosts: 10 |
Somebody made an servomotor (BLDC) with axial flux (like an generator) for CNC? Have some advantage like: - we can build at home if we can build the generator, this mean we can build the servomotor because an original servomotor is expensive or an spindle motor for the router - zero iron loss - High efficiency - Zero cogging torque - Better stability and easier tuning - Smooth operation at very low speed - Reduced audible noise - Low volume - Fewer components - Less generated heat - Maintenance free - Torque is proportional with the current - High efficiency - Low inductance |
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| desert_rain Newbie Joined: 30/12/2011 Location: PakistanPosts: 8 |
Hello every body; I am into building / converting my axial flux alternator to a Brushless DC Motor and preferably Sensored one having hall effect sensors on stater. I am quite new to this whole concept but I have studied through internet to understand the basic concepts of BLDC motor and controller. All I am searching for is schematic and components in the local market and make the controller. Any guideline or help would be highly appreciated. Respectfully Naeem Peshawar, (Pakistan). |
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| Florin Newbie Joined: 28/04/2009 Location: RomaniaPosts: 10 |
This guy made a very good driver. http://www.students.tut.fi/~kontkant/servodrive.php.html For sensors you can use quadrature with index. For quadrature (code wheel) you can use this software http://www.mindspring.com/~tom2000/Delphi/Codewheel.html |
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| desert_rain Newbie Joined: 30/12/2011 Location: PakistanPosts: 8 |
Very difficult. The availability of these parts would be a challenge. |
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