Search found 992 matches

by bobc
Jun 02 2017 7:03am
Forum: General Discussion
Topic: The paris accord
Replies: 7
Views: 785

The paris accord

I really didn't think he'd do it. But it turns out he is much cleverer than all the scientists and the rest of the world, and come the day of reckoning he'll be dead & buried so it makes perfect sense to gamble the votes of some eejits in 4 yrs time against the future of the planet. And while you're...
by bobc
Jun 02 2017 6:03am
Forum: Alternative Energy
Topic: off grid solar e-scooter charging facility
Replies: 25
Views: 3487

Re: off grid solar e-scooter charging facility

Wow - PCBs here already! I shall start building (if it's not too hot on Saturday)
by bobc
May 30 2017 10:43am
Forum: Motor Technology
Topic: Field Weakening VS Gear Box VS Higher voltage battery
Replies: 145
Views: 13778

Re: Field Weakening VS Gear Box VS Higher voltage battery

Can you share any numbers? There are several reasons why not, mostly it was ~10 years ago & I've forgot :) & partly it's my employers company IP..... (kop out I know....) But I think they were looking for a field weakening range from the system of over 2:1 making the back emf worries a real thing; ...
by bobc
May 30 2017 6:42am
Forum: Motor Technology
Topic: Field Weakening VS Gear Box VS Higher voltage battery
Replies: 145
Views: 13778

Re: Field Weakening VS Gear Box VS Higher voltage battery

I had to do some work on a commercial EV controllers' PWM. The issue for us in a commercial development was that if there were an emergency shutdown at high fieldweakening, the diodes in the inverter would jack up the dc link (battery) to well over the intended level resulting in either 1) driven wh...
by bobc
May 25 2017 2:01pm
Forum: Alternative Energy
Topic: off grid solar e-scooter charging facility
Replies: 25
Views: 3487

Re: off grid solar e-scooter charging facility

Thanks Andy, but I'm done with routed PCBs now; flash whisker shorts & badly tinned joints. It has got a load worse with the higher temperature lead free solder. I'm not going to live for ever......
Have a great weekend! Best wishes to pips tom & ailsa
by bobc
May 25 2017 1:55pm
Forum: Motor Technology
Topic: Lebowski's motor controller IC, schematic & setup, new v2.A1
Replies: 1780
Views: 197240

Re: Lebowski's motor controller IC, schematic & setup, new v

With a sinewave inverter your battery DC amps would max out about 20% bigger than motor phase rms amps. That's with 0 field weakening Once you add field weakening you can get the battery amps well above the rms phase amps even above the peak phase amps. nope :) field weakening is a control thing no...
by bobc
May 25 2017 6:59am
Forum: Alternative Energy
Topic: off grid solar e-scooter charging facility
Replies: 25
Views: 3487

Re: off grid solar e-scooter charging facility

After spending lots of time tracking down bugs with the routed circuit above, I've lost patience with it and sent off £25 to china for some proper PCBs
With luck things will go a bit smoother when they arrive :)
by bobc
May 25 2017 5:14am
Forum: Motor Technology
Topic: Lebowski's motor controller IC, schematic & setup, new v2.A1
Replies: 1780
Views: 197240

Re: Lebowski's motor controller IC, schematic & setup, new v

With a sinewave inverter your battery DC amps would max out about 20% bigger than motor phase rms amps.
by bobc
May 23 2017 2:23pm
Forum: Motor Technology
Topic: build your very own Lebowski controller !
Replies: 376
Views: 56474

Re: build your very own Lebowski controller !

couple of things; 1) my SMD version of lebowski's circuit includes all you need to slave controllers together using CAN https://endless-sphere.com/forums/viewtopic.php?f=30&t=87104 2) I'd be very interested in what RS232 info is available while running - is that in one of the threads? can someone po...
by bobc
May 21 2017 11:24am
Forum: Battery Technology
Topic: The "thermal management of LiPo" thread!
Replies: 102
Views: 8919

Re: The "thermal management of LiPo" thread!

here's yet another E•S 10 anniversary wayback trip. http://endless-sphere.com/forums/download/file.php?id=1273 https://endless-sphere.com/forums/viewtopic.php?f=14&t=571 If an idea isn't fatally flawed, there's every chance it has come up before... all good stuff I'd expect paraffin wax to be stabl...
by bobc
May 19 2017 2:07pm
Forum: Motor Technology
Topic: Another SMD lebowski PCB
Replies: 125
Views: 15084

Re: Another SMD lebowski PCB

Been quiet for a bit - working through power supply issues. The main issue is that some retard at work had put a red plug on a black wire & corresponding black plug on red wire (of some clip=on power leads). I've been zapping stuff with negative polarity for weeks. Good trick to remember if you real...
by bobc
May 19 2017 4:43am
Forum: Battery Technology
Topic: The "thermal management of LiPo" thread!
Replies: 102
Views: 8919

Re: The "thermal management of LiPo" thread!

I'll be interested to see how the thing progresses using a paraffin wax PCM. I'd never seen that reported anywhere else when I suggested it further up this thread, & assumed the idea had been discarded, maybe for safety concerns (?). But the numbers did look surprisingly effective (why I made the su...
by bobc
May 19 2017 3:53am
Forum: E-Scooter and Motorcycle General Discussion
Topic: Hub drive vs Chain drive
Replies: 26
Views: 4375

Re: Hub drive vs Chain drive

What about hub motors at this level? QS 17" 14-34kW 80H water-cooled Few thoughts (random sorry) 1) "application sport" - really? with all that unsprung weight? it's bad enough on my emax.... 2) water cooling - seems a bit OTT if we guess at 95% efficient there's 700W to pass which should be doable...
by bobc
May 17 2017 1:12pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: Hub drive vs Chain drive
Replies: 26
Views: 4375

Re: Hub drive vs Chain drive

John in CR wrote:"Incredibly expensive"...You're talking about bicycle ripoff priced stuff. In the size range I need the belts are under $40, which seems pretty reasonable to me. BTW wide means more friction losses, not to mention greater bike and pulley widths.
yep :)
by bobc
May 17 2017 2:11am
Forum: E-Scooter and Motorcycle General Discussion
Topic: Hub drive vs Chain drive
Replies: 26
Views: 4375

Re: Hub drive vs Chain drive

re gates polychain: great product but... incredibly expensive. It's engineered for chain replacement on a roadie bike where the tight side can have over 2000N tension. If you're "gearing the other way" so you have the bigger pulley on the wheel, you don't need the carbon tension members & MUCH cheap...
by bobc
May 15 2017 5:30pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: Hub drive vs Chain drive
Replies: 26
Views: 4375

Re: Hub drive vs Chain drive

A major hubbie advantage is reliability - just the one moving part & that's the wheel. The unsprung weight thing is a real issue on my little emax scooter - hate to think what more power would be like. I'd go for toothed belt rather than chain, less mess, less maintenance, much longer life. The smoo...
by bobc
May 12 2017 5:38am
Forum: Motor Technology
Topic: Switched Reluctance Motors
Replies: 49
Views: 5451

Re: Switched Reluctance - Ideal for DD Hubs?

MMtech - sorry for littering your thread about your mighty motor with ramblings about synchronous reluctance motors, it was a response to lebowski that got out of hand...... everyone else - SRM can stand for "synchronous reluctance motor" or "switched reluctance motor". These are very different beas...
by bobc
May 12 2017 2:17am
Forum: Motor Technology
Topic: Lebowski's motor controller IC, schematic & setup, new v2.A1
Replies: 1780
Views: 197240

Re: Lebowski's motor controller IC, schematic & setup, new v

I knew a researcher who'd made a big 20-odd pole motor for some weirdo application. His cogging torques were so big that occasionally it would stop working as an induction motor and work instead as a switched reluctance (stepper) motor, rotating very slowly backwards with LOTS of torque. (and heat a...
by bobc
May 11 2017 2:29pm
Forum: Motor Technology
Topic: Switched Reluctance Motors
Replies: 49
Views: 5451

Re: Switched Reluctance - Ideal for DD Hubs?

Would you believe I made one (a synchronous reluctance machine) out of a small induction machine.... I'll see if I could "liberate" it from work....... What is the difference between synchronous reluctance and switched reluctance ? Isn't it the same thing ? Nah , the only thing they really share is...
by bobc
May 11 2017 11:53am
Forum: Motor Technology
Topic: Switched Reluctance Motors
Replies: 49
Views: 5451

Re: Switched Reluctance - Ideal for DD Hubs?

Would you believe I made one (a synchronous reluctance machine) out of a small induction machine.... I'll see if I could "liberate" it from work.......
by bobc
May 11 2017 11:38am
Forum: Motor Technology
Topic: Switched Reluctance Motors
Replies: 49
Views: 5451

Re: Switched Reluctance - Ideal for DD Hubs?

MMtech - I guess you're not using usual "totem pole" output bridges?
Also synchronous reluctance want sine excitation & traditional full bridge, but switched reluctance - sort of - don't.... These are different beasts, you're not mixing 'em up are you Bas?
by bobc
May 11 2017 9:23am
Forum: Motor Technology
Topic: Another SMD lebowski PCB
Replies: 125
Views: 15084

Re: Another SMD lebowski PCB

That's good. Having fried an IO port on one, I'll swap it for an empty chip & post it to you to see how it goes. Having the "plug" on the control board makes it almost inevitable that you'll tater it during debug, I'm swapping everything to having a socket on the little board and the "plug" on the i...
by bobc
May 11 2017 9:17am
Forum: Motor Technology
Topic: Switched Reluctance Motors
Replies: 49
Views: 5451

Re: Switched Reluctance - Ideal for DD Hubs?

My (2nd hand) impression is that the sensorless operation has to keep track of the varying (position dependent) leakage inductance to derive rotor position & that it ends up quite a bit different to BLDC...
by bobc
May 11 2017 7:34am
Forum: Motor Technology
Topic: Switched Reluctance Motors
Replies: 49
Views: 5451

Re: Switched Reluctance - Ideal for DD Hubs?

That's a proper job for home- made...... respect!
Luke, do you mean switched reluctance or synchronous reluctance? always a bit concerned about audio noise from switched reluctance, can only really be avoided by massive strength (weight).
by bobc
May 11 2017 6:52am
Forum: Motor Technology
Topic: Another SMD lebowski PCB
Replies: 125
Views: 15084

Re: Another SMD lebowski PCB

Question for Lebowski..... The pickit interface: microchip say that to use the debugger you can't have pullups on PGD and PGC. The standard control board (and this little one) DO have both pullups on these pins AND a PICkit interface. Does this lead to reprogramming problems? - did you ever use the ...