Colin Furze Wheelchair replication , 800 Volt Drive - Page 1
Forum section: electronics / projects

author: patrick1
author_rank: Contributor
timestamp: July 20, 2019, 03:59:51 pm
content: Hi Guys !!. i have been working on this one for 6 months. really cool build, almost as exciting as aviation.Here is the inspiration for my project,https://www.google.com/search?ie=ISO-8859-1&hl=en-AU&source=hp&biw=&bih=&q=colin+furze+wheelchair&gbv=2&oq=colin+furze+wheel&gs_l=heirloom-hp.3.0.0j0i22i30.1776.4795.0.6188.17.17.0.0.0.0.296.2109.7j6j4.17.0....0...1ac.1.34.heirloom-hp..5.12.977.fSaWeAO1XmsI Have designed and built my own motors for the projects, several prototypes so far, and im slowly working my way up through the voltage problems, - so far my motor is up too 720volts - 730 volts without exploding, but i have made some silly compromises that render it inviable. - the electronics that is, - the motor is great ;-)

author: patrick1
author_rank: Contributor
timestamp: July 20, 2019, 04:00:59 pm
content: please be gentle ;-D

author: patrick1
author_rank: Contributor
timestamp: July 20, 2019, 04:06:09 pm
content: really my issue is the VB0e etc ratings on these transistors, - etc etc,When i connected the Base, From the Collector. it is leaking through and activating the transistors, - , EG it may work fine @ 200v, but problems @ 600v.Also Back feeding and charging the gate, via the emmiter,The best i could get the motor running, is using a completely separate power supply for each transistor, - in this case, small transformers with high resistance secondaries.but this is wasteful of money and input power., it will run reliably at 700volts but with less torque than should be avaliable. (which is ok), - but at 2watts per external transformer, = 8watts total. ... it is almost doubling my unloaded input power.

author: Circlotron
author_rank: Super Contributor
timestamp: July 21, 2019, 12:55:17 pm
content: Those four 10A10 diodes are a disaster waiting to happen. If any of the mosfets turn off while they are still passing current, there is absolutely nothing to stop the interrupted motor current putting a very high voltage across that mosfet. I think the diodes should be replaced by wire links. Of course, you may then run into issues with reverse recovery time of the parasitic body diode in the mosfets, and current crowding during that recovery leading to device failure. Power electronics is not as easy as some YouTube videos would have you believe.

author: patrick1
author_rank: Contributor
timestamp: July 21, 2019, 04:03:45 pm
content: I just recorded a video update of the motor, as it is, today.hehe indeed, the backemf's were a problem from the start of this project, i found that after about 280volts, the transistors would simply blow, even though they are NTP rated. - but they are still a concern because of how old they are technologically. ... but i solved the offtime emf problems with a paralell capacitor across the motor, (see the MOT cap, in the video)but after i achieved about 400volts, i noticed the rotation of the magnets were generating a voltage, that exceeded the input voltage, - which reduces the input current, but it also backfed the drain pin, and wouldnt allow the transistor too switch off properly., but some diodes fixed that (albeit slow ones)and after i hit 500v, the collectors started too leak on the bottom end of the H Bridge., which is still a problem, - i had too remove darlington pairs at that point, and drive the FETS with seperate power supplies, - thats my biggest problem right now, - but running up too the max of my power supply right now, 740 volts, - . im about too replace the base drive transformers with some tiny SOC package dedicated dc-dc converters. - but i give that 50/50 change ... at best.anyway when the big motor gets built next, i might consider just making my own base drivers with IR leds and solar cells. - either that or just bite the bullet and use a commutator

author: MagicSmoker
author_rank: Super Contributor
timestamp: July 21, 2019, 07:56:19 pm
content: Quote from: patrick1 on July 21, 2019, 04:03:45 pmSo, your motor generates a counter-EMF that exceeds the applied voltagewithoutexerting a braking torque on the shaft? Looks like it's time to break out the tin foil helmets, folks.

author: DBecker
author_rank: Frequent Contributor
timestamp: July 21, 2019, 08:46:42 pm
content: I'm pretty sure he meant that the commutation "kick" exceeded the input voltage.Physical design is a big deal with high voltage, high current motor control. Parasitics that wouldn't matter in low power design become major problems. I designed a 160V controller for a series wound DC motor in a homebuilt EV, and we spent a lot of time tuning the physical layout, switching speeds and capacitor bank to limit the commutation spike.

author: patrick1
author_rank: Contributor
timestamp: July 21, 2019, 09:04:01 pm
content: actually its fascinating !!. i will share a scope shot tomorrow, about to go bed, @ 5 am :=DBUT, when view on a scope, THE TRACE is a ; 500v Square wave, - with a 600~v sine wave over the top (from the magnets),Also, when this coil has no rotor, - the current is 200ma, - but when the rotor spins, current drops too 5ma~. - this is normal for a typical dc motor, but typically magnets are not so strong, and coil, not so many turns ;-D. ,- this makes the difference.

author: BrianHG
author_rank: Super Contributor
timestamp: July 22, 2019, 02:39:09 am
content: Quote from: patrick1 on July 20, 2019, 03:59:51 pmI'm sorry to tell you this, but, nowhere in that video has that guy on that wheelchair exceed 25mph, if he even gets that fast...

author: paullo
author_rank: Newbie
timestamp: July 23, 2019, 04:26:08 pm
content: Quote from: BrianHG on July 22, 2019, 02:39:09 amHe has set an official world record doing 71mph on ithttp://www.colinfurze.com/fastest-scooter.html

author: patrick1
author_rank: Contributor
timestamp: August 28, 2019, 11:49:27 am
content: Hi guys,this particular newman experiment, ( the last 2 motor builds actually ). as pictured, .... were designed too figure out the importance of coil resistance.---- and the answer is, - resistance is used too determine the rpm of the motor (along with rotor height), ,,, and the overall COP and torque is determined by the weight of copper (along with rotor height), !!so basically a tall rotor gives you more torque and less speed ;=D ... and a greater weight in copper, aka larger magnetic field interaction will increase efficiency. one reason why joseph called his second last motor build "the big eureka" - on a semi trailer. -... and his last, a desk fan.i have a few more experiments after this. - and the next 2 motor builds, are for furze style fun

author: Yansi
author_rank: Super Contributor
timestamp: August 28, 2019, 12:45:27 pm
content: Why does this thread have that SPAM/SCAM like title and is full of some free-enerdzi like bullshittery?

author: patrick1
author_rank: Contributor
timestamp: August 28, 2019, 01:52:56 pm
content: Quote from: Yansi on August 28, 2019, 12:45:27 pmhopes and dreams ?you know Yansi, in my few months on this forum, i have not seen any of what you describe..... also, the prerequisites of this dare, is too make your own motor, efficient enough too move my tall and subtle ass, off too the races

author: Yansi
author_rank: Super Contributor
timestamp: August 28, 2019, 02:24:43 pm
content: Then you should probably start working from a real engineering concepts, not from a pseudo-science.

author: patrick1
author_rank: Contributor
timestamp: August 28, 2019, 02:36:26 pm
content: hello kind sir, have you ever studied electronics ?, the principles are perfectly mainstream, not strictly beer physics

author: Yansi
author_rank: Super Contributor
timestamp: August 28, 2019, 02:42:56 pm
content: Yes, I have successfully studied electrical engineering, specifically electric drives and traction, so I probably should know at least something about motors.Your project unfortunately looks like a typical free energy one, sorry to say. Using a tens of pounds of copper plus 800V to produce just a couple of watts mechanical power is either stupid, naive or sad. or you are probably just a troll.Why don't you post some engineering data of your build so we can discuss it further, what can be improved? So far we have seen only a fancy clickbaity title.

author: MagicSmoker
author_rank: Super Contributor
timestamp: August 28, 2019, 02:48:45 pm
content: Much as I expected, the OP has veered off into pseudoscience territory. The Newman "motor" claims to output more mechanical energy than electrical energy input by - get this - converting some of the mass of the copper windings into energy, a la Einstein's famous equation.https://en.wikipedia.org/wiki/Newman%27s_energy_machine

author: Bud
author_rank: Super Contributor
timestamp: August 28, 2019, 03:58:17 pm
content: Quote from: patrick1 on August 28, 2019, 02:36:26 pm

author: patrick1
author_rank: Contributor
timestamp: August 30, 2019, 10:44:53 am
content: Quote from: Yansi on August 28, 2019, 02:42:56 pmHello Mr Yansi, i have posted some engineering data, and details of the problems encountered with the inner workings, - and the solutions. please share with me, the kind of data you would like too see, - and i would be very interested too oblige.PLEASE NOTE, THIS VIDEO IS ABOUT TECHNICAL ASPECTS OF THE BUILD. NO PSEUDO HOOEY