Search found 2737 matches

by weber
Tue, 17 Feb 2009, 16:46
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 80487

AC motors, multipoles, torque

Hi weber. Do you know how Ross overcame the problem of lubricating the rear oil seal (around the tail-shaft slip-yoke) without swamping the front motor bearing with oil? This is my current concern with using my tail-shaft housing. Sorry - a bit off topic here. Not too off topic since one aim of man...
by weber
Tue, 17 Feb 2009, 04:06
Forum: Electric motors and controllers
Topic: AC or DC?
Replies: 99
Views: 16670

AC or DC?

I was looking for the thread entitled "Induction motors or custard? and couldn't find it, so this thread will have to do. :-) "What the hell is he on about?", I hear you say. Well it happened like this: I was sitting on a stool in the kitchen eating some delicious firm vanilla custard and jelly whil...
by weber
Mon, 16 Feb 2009, 20:15
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 80487

AC motors, multipoles, torque

I've come to the conclusion that with a powerful enough controller / batteries, none of the star/delta/series/parallel/pole/dahlander switching is helpful. I.E. if your controller can put out enough amps for peak torque at the low voltage (in my case 174A @ 240V for 350Nm @ ~3000rpm), then star / d...
by weber
Mon, 16 Feb 2009, 18:52
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 80487

AC motors, multipoles, torque

I was talking to an electrical engineer friend on the weekend, about Coulomb's and my AC EV project and he mentioned that he'd worked on a lathe that had used an off-the-shelf high frequency (400 Hz) induction motor driven from a stock standard Control Techniques VF drive. So I googled "high frequen...
by weber
Mon, 16 Feb 2009, 10:02
Forum: Batteries, charging, management and monitoring
Topic: Thundersky LFP sag at 5C
Replies: 33
Views: 6703

Thundersky LFP sag at 5C

Another thread on the Headway cells. Seems the odd dud cell gets shipped.
http://www.endless-sphere.com/forums/vi ... &start=195
by weber
Mon, 16 Feb 2009, 08:20
Forum: Batteries, charging, management and monitoring
Topic: Thundersky LFP sag at 5C
Replies: 33
Views: 6703

Thundersky LFP sag at 5C

If a company won't back its own product with a lengthy warranty then why should a customer of that company have more faith in the product they provide than the manufacturer themselves? I totally agree. Take the price, divide by the warranty period and divide by the amp-hours. Which has the lowest d...
by weber
Mon, 16 Feb 2009, 05:27
Forum: Batteries, charging, management and monitoring
Topic: Thundersky LFP sag at 5C
Replies: 33
Views: 6703

Thundersky LFP sag at 5C

Shaun says what he wants to say entirely independantly of me. I don't pay him to say "nice things" or give him any special favours in any way. My apologies Armin, I didn't mean to offend either you or Shaun. I'm sure you sell the product because you believe in it, not the other way 'round. And it's...
by weber
Mon, 16 Feb 2009, 04:20
Forum: Electric motors and controllers
Topic: AC or DC?
Replies: 99
Views: 16670

AC or DC?

Actually 415/sqrt(2) ~= 293v, the minimum bus voltage needed to generate 415v 3-phase. I may have incorrectly described that as 340v, i.e. 240*sqrt(2). Er. The minimum DC bus voltage to generate 415 V 3-phase is 415 * sqrt(2) = 587 V, as someone else already said. I presume you meant +-293 V. But D...
by weber
Mon, 16 Feb 2009, 02:09
Forum: Batteries, charging, management and monitoring
Topic: Thundersky LFP sag at 5C
Replies: 33
Views: 6703

Thundersky LFP sag at 5C

Thanks lithbattboss, You are, of course, Armin Pauza, an Australian seller of BMI/LifeBatt products. I have already emailed Shaun Williams and asked him to respond here. It would be useful to know if you have you offered to reward Shaun in any way for any sales he might assist you with. Regards, -- ...
by weber
Sun, 15 Feb 2009, 20:51
Forum: Batteries, charging, management and monitoring
Topic: Thundersky LFP sag at 5C
Replies: 33
Views: 6703

Thundersky LFP sag at 5C

so 5C from TS cells is doable, you just wont be able to do better than 3C during winter. perhaps if you really heat up the cells, the fabled 10C is possible are the lifeBatts similarly affected by heat? I can't find any info on that. I'd guess they would be similar since the chemistry is the same. ...
by weber
Sun, 15 Feb 2009, 03:00
Forum: Electric motors and controllers
Topic: How Does Regeneration Work
Replies: 46
Views: 7967

How Does Regeneration Work

on a DC motor and controller doing regen the controller is basically shorting out the motor briefly to build current, then releasing it - which gives a voltage spike when the magnetic field collapses. That spike goes to the battery pack via the freewheel diodes, and different duty cycles can give m...
by weber
Tue, 10 Feb 2009, 22:30
Forum: Electric motors and controllers
Topic: How Does Regeneration Work
Replies: 46
Views: 7967

How Does Regeneration Work

Hi EVLearner, There are many things going on at once in the AC EV situation. To explain AC regenerative braking let's start with the simpler situation of a 2-pole 3-phase induction motor direct on line at say 415 V 50 Hz. Actually, let's simplify it a little more and give it a permanent magnet rotor...