It has five data/signal outputs from the controller to the motor in addition to three heavy duty power wires. Not sure exactly where the power wires come from since the stuff is encased a glob of glue.
One of those signal wires is purple, the other four are black. Is that common? If so, what's it called so I can find some information about it.
Be happy to supply more pictures if needed.
Thanks.
Brushless motors often (but not always) have either hall sensors (three signals) or an encoder (two signals, sometimes differential pairs, sometimes with an extra "zero position" signal). These often need power (+5v/gnd), so three halls plus power = 5 wires makes sense.
If you watch these signals with an oscilloscope, hall sensors would show a three-phase signal about 1x to 6x the RPMs of the motor (in sync with the power wires), while encoders would have two quadrature signals in the 500x to 4000x the RPMs range.
As someone pointed out in another thread, these are probably for a set of Hall-effect sensors which allow the controller to monitor the rotation of the poles, and do the switching/commutation via electronic means.
The usual arrangement would be one wire to supply a positive voltage to power the Hall-effect sensors, one wire for ground, and one output signal wire per sensor.
The brushless drivers that I know of that use encoders also use hall- effect commutation for start-up, and only start using the encoder once an index has been found.
But driving brushless motors is like skinning cats -- there's more than one way.
-- Tim Wescott Wescott Design Services
is three-wire, phases-only, and sensing is by observing voltages on unconnected phases.
Bosch/Mercedes motor controller chip project (late '90's) ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et |
Oooops! FOUR wires (you need center of wye to +12V). ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et |
Den torsdag den 3. september 2015 kl. 16.37.39 UTC+2 skrev Jim Thompson:
only unipolar drive?
sensor less doesn't work when you need high torque at zero or very low rpm
-Lasse
Built-in start oscillator (AND the hard part... sensing rotation in wrong direction: wind driven (*) when un-powered makes it tricky to stop the rotation and reverse direction ;-)
(*) Mercedes heater and A/C blower
I actually used a leaf blower in my lab to test the breadboard. ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et |
See just about every model airplane electric motor and electronic speed controller. It does seem to work well as long as you don't need to deliver any torque at low speed.
-- Tim Wescott Wescott Design Services
I utilized a start oscillator to get it going. It was a crazy project. Controlled acceleration... no "whine" sound allowed... final test was chief engineer sticking his head in ductwork and listening ;-) ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et |
Why don't you look at RC vehicle motors, motor controllers and batteries. 1000's to choose from.
Here's a 2-1/2 hp motor for $52.00
The rpm is high, although it's low for these kind of motors.
295 RPMs per volt. 68 amp max, 55 volt. Quick calculation, 48V battery, 14,100 rpm, 8 to 1 ratio, wheel turns 1681 RPM, 26" wheel, 30 mph. I don't know if the current would be too high.Check my math, one time through, didn't double check.
I've 'thought' about a couple of these type motors on a gokart.
Miikek
Here's an 80 amp motor controller for $48.00.
270 amp burst.
Mikek
amdx wrote in news:msa0ni$b0r$ snipped-for-privacy@dont-email.me:
I've looked at lots.
The max no load RPM should be no more than about 400.
There is the motor, the controller, the batteries, the charger... Then there is attaching it to the bike. That requires low enough RPM, the right size sprockets attached to the drill and to the bike.
Designing stuff and building stuff are two completely different things. It's really amazing the obstacles one encounters when actually building something. Even the simplest of ideas can be blocked.
Yup, my driver board did exactly that:
Heh. I had that problem when I started the project. "Which of the following seventeen or so methods do I feel like implementing THIS time?" I think I tried five before I settled on one.
"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
Curious, as an automotive project, did they want you to sign away your first-born son as collateral? Or was this kind of project far enough down the design chain not to be so draconian? (Or did you tell their lawyers to stuff it and come back with just the parts you approve of? ;-) )
Tim
-- Seven Transistor Labs Electrical Engineering Consultation
Everything was quite friendly, unwanted sounds were just part of the spec. ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et |
"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...
I wasn't doubting that; such would be understandable for a luxury vehicle!
On a related note, once upon a time we had some guys from LANL over; noise was part of the spec (probably just pulled from OSHA, something like 85dB), so one of the guys got out his iPhone and listened in.
It probably didn't help that the microphone apparently pegged at 85dB, and we were in the middle of a noisy shop to begin with. ;o)
Tim
-- Seven Transistor Labs Electrical Engineering Consultation
I made a plan (design) got a motor, a contoler, the batteries, a charger and fabricated all the parts needed to put these on a gokart. all was fine for about 5 years when one of my batteries failed.
I did get 4 group 27 deep cycle batteries after I had it all working.
There are many ways to get the the drive from the motor to the wheel. What limitation have you made yourself. Is your problem uncoupling the motor from the wheel when you just want to pedal?
Did anyone check my math, 8 to 1 seems pretty easy.
Well done!
Sure, if you have access to a machine shop. Or at least a metal lathe.
That's a good thought, but not my current concern.
Efficiency is everything to me. The idea is to make a reasonably powerful bike that is easy to build from readily available components.
Besides the controller, batteries, and charger... An appropriate motor would do the trick. A powerful and compact motor (with controller, batteries, and charger) that is geared to no more than about 400 RPM would make building an electric bike easy. Cordless drills/tools are the closest I've come to satisfying that.
Or you can use a hub motor as someone else mentioned. Hub motor technology will probably be ripe for me in the not-too-distant future.
LOL, I was about to suggest, find some kid in High School and have him do it in his shop class. Times have changed, I could have whipped up parts in my fully equipped HS shop. 10 or 15 lathes, 5 or 6 mills, a shaper, drill presses, foundry, tool shed. Not to mention the woodworking shop. My son had none of this at his HS.
I don't think you'll find the drill motors to be highly efficient motors. The RC motors do give characteristics at the highest efficiency.
What are you turning at 400 RPM? Ok, went through the math, I did make an error in my math, didn't check where. Looks like your goal is to turn a 26 in wheel at 400 RPM for a max speed of 30.9 MPH. The motor I suggested would need a 35 to 1 ratio. Not impossible two 6 to 1 reductions. The idea of driving the wheel without any gear reduction doesn't set well with me. You're putting a 13" lever on the shaft of the motor. Hitting a bump will cause a large stress on the gears in the drill motor.
Hub motors were a great idea someone's mind clicked on. Mikek
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