Search found 3173 matches

by Lebowski
Aug 24 2011 5:56am
Forum: Motor Technology
Topic: Not simple BLDC controller It RUNS! :)
Replies: 574
Views: 54562

Re: Not simple BLDC controller

I was referring to learning to develop software :) Lebowski, try an AVR, you'll like the 4x+ speed increase over the PIC ;) With the AVR I really dislike their datasheets, impossible to read while those of PIC are very clear. Plus I didn't find any programmer on their site, same for good assembler ...
by Lebowski
Aug 24 2011 1:17am
Forum: Motor Technology
Topic: Not simple BLDC controller It RUNS! :)
Replies: 574
Views: 54562

Re: Not simple BLDC controller

It's a piece of cake Arlo, you'll see :) Well, :oops: , in a 16F88 I run a control loop to control the current through a motor (so a current based throttle control). This comprises a 1st order integrator implemented with 16 bit fixed point math (including fixed point multiplications and in addition...
by Lebowski
Aug 23 2011 7:40am
Forum: E-Bike General Discussion
Topic: Cromotor + MethTek Monster 24FET + 20S lipo build
Replies: 311
Views: 41160

Re: Modding chinese ebike (gift) - any advice?

Read some more, for many of us on the sphere, 2000 w is baby bike wattage. I'm a bit different, having tried 4000 watts, I found motor reliability much better using no more than 1500 watts. So 72v 20 amps, 48v 30 amps, is my prefered operating zone. I agree, this is a mostly American forum. Cheap c...
by Lebowski
Aug 23 2011 3:37am
Forum: General Discussion
Topic: Luke in Germany
Replies: 71
Views: 3489

Re: Luke in Germany

For you guys that know the speed limits on the continent and in Germany... you know how it is here in the states, 5mph over, no issue at all; 9mph over, likely no issue. 10+ and you could get stopped depending on how many donuts they got free that day. When Germany says 30Km/hr what is the "margin?...
by Lebowski
Aug 23 2011 2:02am
Forum: Motor Technology
Topic: Not simple BLDC controller It RUNS! :)
Replies: 574
Views: 54562

Re: Not simple BLDC controller

cool stuff 8) let us know how you get on with the included course, I'm very curious as to how good and elaborate it is.
by Lebowski
Aug 23 2011 1:07am
Forum: E-Bike Technical
Topic: I think I over did it
Replies: 31
Views: 1692

Re: I think I over did it

yopappamon wrote:Perhaps a resistor in series with the throttle would be the cheapest solution. Cycle Analyst the best solution.
or a zener diode
by Lebowski
Aug 22 2011 11:03am
Forum: General Discussion
Topic: Luke in Germany
Replies: 71
Views: 3489

Re: Luke in Germany

Arlo1 wrote:Carefull man chocolate makes you think.
well, :oops: $159 is about 100chf which buys you, what, 1 kg ? (2 lbs in US money)
by Lebowski
Aug 22 2011 10:44am
Forum: General Discussion
Topic: Luke in Germany
Replies: 71
Views: 3489

Re: Luke in Germany

liveforphysics wrote:I'm in Zurich right now, going to a chocolate factory on the lake, spruengl.

Meet me if you are close!
The 'badi' (swim-site) opposite the factory is my swimming spot :D I live 5 minutes away from there.

About boat rides, we still have some steam ships on this lake
by Lebowski
Aug 22 2011 4:54am
Forum: Motor Technology
Topic: Does anyone seal their windings?
Replies: 17
Views: 1317

Re: Does anyone seal their windings?

There is a considerable amount of force on the wires, so if they are loose, they will move. With thick heavy wires, it's not as much of a concern. As I understand it, there is no force on the wires. All the reaction force is taken by the core. Isn't this right? No, there can be force on the wires (...
by Lebowski
Aug 22 2011 2:33am
Forum: General Discussion
Topic: Luke in Germany
Replies: 71
Views: 3489

Re: Luke in Germany

Hope you enjoy my country (Switzerland) :D You picked an excellent week, will be hot and sunny :D That's what they have been telling me here as well. Evidently the previous week was rainy and cold, this week has been roughly exactly like California's weather, nicely warm and dry. :-) I have been en...
by Lebowski
Aug 22 2011 1:44am
Forum: Motor Technology
Topic: Not simple BLDC controller It RUNS! :)
Replies: 574
Views: 54562

Re: Not simple BLDC controller

Some stuff I learned the hard way :? when working with optocouplers: make sure your power transistors are off when the LED part of the optocoupler is off ! Have you guys thought of using a class D audio driver like this: http://www.silabs.com/products/audiovideo/class-d-audio-drivers/Pages/Si824x.as...
by Lebowski
Aug 22 2011 1:11am
Forum: General Discussion
Topic: Luke in Germany
Replies: 71
Views: 3489

Re: Luke in Germany

Hope you enjoy my country (Switzerland) :D You picked an excellent week, will be hot and sunny :D
by Lebowski
Aug 19 2011 8:42am
Forum: E-Bike General Discussion
Topic: Weird new bike frame
Replies: 4
Views: 453

Re: Weird new bike frame

Reminds me a bit of a Norton featherbed frame...
by Lebowski
Aug 19 2011 8:03am
Forum: Battery Technology
Topic: single cell (1sXp) charger proposal
Replies: 4
Views: 557

Re: single cell (1sXp) charger proposal

But air core transformers doesn't have closed flux path, so they will have a bad magnetic coupling between primary and secondary, right? Only like half of the coil will transfer energy and the other half will act like an inductance in series with the transformer winding. Or is it possible to layout...
by Lebowski
Aug 19 2011 7:15am
Forum: Battery Technology
Topic: single cell (1sXp) charger proposal
Replies: 4
Views: 557

Re: single cell (1sXp) charger proposal

The general plan seems doable, altough there are a few solutions which may not work well, for example the gate drive on primary, and the air core transformer, and missing resistors on LEDs. Is the gate drive also used for communication? Why the diode on the discharge transistor? Yeah OK, but the dr...
by Lebowski
Aug 19 2011 4:39am
Forum: Motor Technology
Topic: My homemade bicycle motor, version 1
Replies: 8
Views: 4494

Re: My homemade bicycle motor, version 1

StudEbiker wrote:That looks to be some serious hardware in the background there. :wink: I'd be worried about the bi-pods scratching that nice floor though. :)
It's cheap laminate :D I'll never have to buy a 7.5 mm drill ever again :twisted:
by Lebowski
Aug 19 2011 3:52am
Forum: Battery Technology
Topic: single cell (1sXp) charger proposal
Replies: 4
Views: 557

single cell (1sXp) charger proposal

Hi, Since I'm at the point where I need to use batteries (as my lab supply is too weak) I want to re-use some Li-ion cells from old notebooks. Just for initial testing. Since also later I want to make my own pack using LiFePo cells I'm now busy with the charger / BMS. I think what I want to build is...
by Lebowski
Aug 18 2011 5:18am
Forum: Motor Technology
Topic: My homemade bicycle motor, version 1
Replies: 8
Views: 4494

Re: My homemade bicycle motor, version 1

Finally got the thing strapped to my bicycle and managed to put 175 W through
it :D this is however the limit of my laboratory DC power supply :( Need to get
my hands dirty with batteries now
DSC00343_scaled.JPG
by Lebowski
Aug 18 2011 2:26am
Forum: E-Bike Technical
Topic: Hall Sensors'b'Gone
Replies: 223
Views: 11536

Re: Hall Sensors'b'Gone

I'm not exactly sure what you mean by 'motor terminal voltage sensing'? /Mattias I run an algorithm which measures the back-emf of the unconnected phase. To determine the switching point of the (low side) NMOS I continuously measure until the unconnected phase drops below the negative supply. Then ...
by Lebowski
Aug 18 2011 1:40am
Forum: E-Bike General Discussion
Topic: Forced Air through axle? (Cooling Hole placement)
Replies: 54
Views: 2185

Re: Forced Air through axle?

My motor has a bit of forced cooling. As it spins the air in de motor starts to rotate and if flung outward by centrifugal force. This creates low pressure in the middle of the motor, air is sucked in through the hole in the side of the rotor through which the axle goes. The effect is small though. ...
by Lebowski
Aug 18 2011 1:06am
Forum: E-Bike Technical
Topic: Hall Sensors'b'Gone
Replies: 223
Views: 11536

Re: Hall Sensors'b'Gone

Dou you also use mid-point sensing like in AN1160 ?

Am I the only one doing motor terminal voltage sensing ?
by Lebowski
Aug 17 2011 2:48am
Forum: E-Bike Technical
Topic: Hall Sensors'b'Gone
Replies: 223
Views: 11536

Re: Hall Sensors'b'Gone

full schematic, assembler code ?

please ? :D

I agree by the way, there should be a controller technology / controller algorithm section...
by Lebowski
Aug 17 2011 2:36am
Forum: Motor Technology
Topic: Not simple BLDC controller It RUNS! :)
Replies: 574
Views: 54562

Re: Not simple BLDC controller

How about this for a gate-drive (optocoupler + gate drive circuit in 1):

VO3120:

http://www.farnell.com/datasheets/485119.pdf
by Lebowski
Aug 17 2011 2:04am
Forum: Food and Drink
Topic: Meanwhile in Germany....
Replies: 6
Views: 541

Re: Meanwhile in Germany....

liveforphysics wrote:
EMF wrote:Gut Tschüss! Viel Vergnügen! :mrgreen: Germany is very very nice. I bet you will enjoy yourself.

Considering I'm going for electric motorcycle racing development, yes, I do imagine I would be hard pressed to have a bad time. :-)
Is the 'nitrolympics' this weekend in Hockenheim ?
by Lebowski
Aug 16 2011 8:36am
Forum: Motor Technology
Topic: The concept of "amps drawn" by a motor?
Replies: 70
Views: 4616

Re: The concept of "amps drawn" by a motor?

Okay I am reading and rereading these posts and trying to make it sink in. Thanks to all for your responses. Sorry bro, I made a typo. I meant: "The battery's pushing, the load is resisting ..." The battery's voltage is like a pressure, pushing electrons out of it. The load (which in this case is t...