Search found 4302 matches

by coulomb
Sat, 28 Feb 2009, 16:54
Forum: Technical and conversion discussion
Topic: Prius Plugin
Replies: 10
Views: 2106

Prius Plugin

Szencorp wrote:In 2008, Szencorp funded Sydney’s Institute for Sustainable Futures to create Australia’s first PHEV.
That sounds like it might have been a one off project.
by coulomb
Sat, 28 Feb 2009, 01:39
Forum: General EV Discussion
Topic: General Electrical Question
Replies: 108
Views: 10040

General Electrical Question

Ok what about something like Thunderskys for cheaper conservative driving and ultracaps to supplement for the traffic light grand prix? To address the idea of ultracaps, I'm not that fussed with them at present. To use them really effectively, you really need a separate controller (admittedly less ...
by coulomb
Sat, 28 Feb 2009, 01:21
Forum: General EV Discussion
Topic: General Electrical Question
Replies: 108
Views: 10040

General Electrical Question

Ok what about something like Thunderskys for cheaper conservative driving and ultracaps to supplement for the traffic light grand prix? What discharge rate the batteries are rated at has nothing to do with how high they can be discharged at. Thunder Sky batteries are considered low discharge rate b...
by coulomb
Fri, 27 Feb 2009, 20:26
Forum: General EV Discussion
Topic: General Electrical Question
Replies: 108
Views: 10040

General Electrical Question

If using low rate cells, make the pack big enough that continuous current is less than 1C. Err, that's nice if you have unlimited money and weight to spare, but in my case it would add something like $30K and 600kg (tripling the pack). Sometimes you just have to accept the hit to capacity (maybe we...
by coulomb
Fri, 27 Feb 2009, 07:52
Forum: General EV Discussion
Topic: General Electrical Question
Replies: 108
Views: 10040

General Electrical Question

i should point out, that the TS cells are rated at 0.3C. when discharged at 1C, TS cells have only 90% of rated capacity. Huh? Maybe you are thinking of TS cylindrical cells. The Thunder Sky Instruction Manual clearly states that maximum continuous (they say "constant") discharge current is 3C (the...
by coulomb
Thu, 26 Feb 2009, 01:47
Forum: Technical and conversion discussion
Topic: Prius Plugin
Replies: 10
Views: 2106

Prius Plugin

Just for the curious here is a web site from someone who did a Prius inverter teardown. Wow, fascinating stuff. It seems that the Prius has a boost converter (boosting the battery to some 500v) that is indeed bidirectional, similar to what ev2go suggested, and which I didn't recommend. But I guess ...
by coulomb
Wed, 25 Feb 2009, 21:03
Forum: General EV Discussion
Topic: General Electrical Question
Replies: 108
Views: 10040

General Electrical Question

Still haven't quite worked out how the controller can put out more amps then are being drawn from the battery pack. Is this applicable to AC as well? Essentially, you store the current into an inductor's magnetic field. If you want to increase the current tenfold, (and hence divide the voltage by 1...
by coulomb
Wed, 25 Feb 2009, 20:44
Forum: General EV Discussion
Topic: General Electrical Question
Replies: 108
Views: 10040

General Electrical Question

If I choose an AC motor... say the Azure AC90 or AC55, but only have a battery weight allowance for say 45 x 90Ah TS (144v -135kgs) and ran an inverter to step the voltage up to 312v, would this give me roughly 312v – 40Ah? Well, yes it would, less losses. Also going through an inverter to step up ...
by coulomb
Wed, 25 Feb 2009, 19:15
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 18364

Electric Beemer

Maybe this graph below will help see the FULL picture. Well, it filled in a few gaps for me, thanks Richo. For example, I didn't realise that from zero to nominal speed they keep the slip constant. So it's just voltage that varies in that region (classically). The behaviour when the breakdown torqu...
by coulomb
Wed, 25 Feb 2009, 17:53
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 18364

Electric Beemer

Sorry, still flame on Ts. (you do mean torque at zero RPM with 50Hz applied I guess) Not breakdown or pullout torque ? Weber, I think he was talking about this snippet of mine: Also, I suspect that the family of torque/speed curves converges on Ts as the speed approaches zero. As the current speed ...
by coulomb
Wed, 25 Feb 2009, 07:12
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 18364

Electric Beemer

Hi, I have been in discussion with ABB engineers for a very similar BMW project and they have come up with this motor 3GAA 182 102-A• C      22 kW 4 Pole M3AA 180 L B3 Foot Mounted Could I have some opinions on suitability please and performance and weight figures that you know of and ability to ru...
by coulomb
Wed, 25 Feb 2009, 06:34
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 18364

Electric Beemer

Big flame on the stall torque thinking though. When running on a VFD, nothing left of the breakdown torque should be considered since the normal curve is just shifted back toward zero RPM by the frequency being lowered. You never visit stall torque, that is a DOL parameter. Brickbat accepted. Thoug...
by coulomb
Wed, 25 Feb 2009, 05:22
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 18364

Electric Beemer

The graph below is from the new ABB industrial performance cattledog. It shows at 100Hz the torque would be 42% of Tmax. Right. This is continuous torque. It is limited by power dissipation. The more power, the the harder it is for the motor to get rid of the heat. At something under 50Hz, the torq...
by coulomb
Wed, 25 Feb 2009, 05:04
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 18364

Electric Beemer

Can you, or anyone, please explain how this torque boost trickery works? Here is my picture: at lower than synchronous frequencies, the controller is not yet applying its maximum voltage. The usual rule is to apply a constant volts per hertz that will result in the motor getting full voltage at nom...
by coulomb
Tue, 24 Feb 2009, 20:26
Forum: Batteries, charging, management and monitoring
Topic: Volts AHA and TS Lithiums
Replies: 21
Views: 3225

Volts AHA and TS Lithiums

Sorry where did the 40Ah come from I thought we were talking 90Ah. Oops http://forums.aeva.asn.au/smileys/smiley9.gif     From a brain short circuit. 40AH TS are one of the main contenders for our MX-5 conversion. So even if long term discharge needs to be 0.8C 45*3.2*90*0.8= 10.36kW? I am missing ...
by coulomb
Tue, 24 Feb 2009, 17:46
Forum: Batteries, charging, management and monitoring
Topic: Volts AHA and TS Lithiums
Replies: 21
Views: 3225

Volts AHA and TS Lithiums

Another issue is the max discharge rate. 90AH will be 3C Pulse to 5C if you have to. So 270A cont. and 450A peak. So that's 450A x 2.5v x 45 = 51kW peak electrical. Maybe 35kW mechanical, which is a bit weak for maximum power. The 160AH would give more peak power. I read somewhere that while the "c...
by coulomb
Tue, 24 Feb 2009, 06:55
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 18364

Electric Beemer

woody wrote: I did a little graph comparing direct drive and gears power at the diff.

Wow, thanks, Woody! The motor and controller will soon be the focus; we may pick up the donor vehicle soon.
by coulomb
Tue, 24 Feb 2009, 06:27
Forum: Electric motors and controllers
Topic: AC or DC?
Replies: 99
Views: 16627

AC or DC?

Yeah I don't think it will work with half the voltage. Too low for the controller. Actually, the AC24LS Product Sheet says you can run the motor in delta (or maybe order a different version that is pre-wired in delta) and run it at 156v. You only get 3/4 the power, but there is no reason you can't ...
by coulomb
Mon, 23 Feb 2009, 06:54
Forum: Batteries, charging, management and monitoring
Topic: Power Consumption for Dummies
Replies: 144
Views: 20789

Power Consumption for Dummies

so if we put a 5 ohm resistor in series between the battery and control will that help reduce the amps before it gets to the control? (the electrician just wants me to check with u guys if his math is right,he also said the 5ohm reisiter would need to be 50-100w or higher..preferably higher. Well, ...
by coulomb
Sun, 22 Feb 2009, 07:19
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 18364

Electric Beemer

If a gearbox is used then the starting torque becomes a moot issue. Right, so you could start in third gear say with a 4-pole motor, and get about the same torque as a 2-pole motor starting in first. But industrial ACIMs have limited speed; perhaps as low as 4500 rpm. So the 4-pole motor would prob...
by coulomb
Sun, 22 Feb 2009, 06:23
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 18364

Electric Beemer

http://forums.aeva.asn.au/uploads/274/BMW_ICEvEV.JPG Um, this diagram shows peak torque and power, right? So the power should fall off at 1/f and the torque should fall off at 1/f^2, should it not? Woody, can you back me up here? The continuous torque and power have the shapes you have drawn, but b...
by coulomb
Sat, 21 Feb 2009, 17:53
Forum: Electric motors and controllers
Topic: Motor efficiency Vs Amps used
Replies: 22
Views: 5356

Motor efficiency Vs Amps used

First looking at the Impulse it uses 449 Amps to produce 70 ft lbs, the Warp 11 uses 290 Amps, and the Warp 13 uses 250. Now they are all running at 72 volts but the Warp 13 produces the same torque at nearly half the Amps of the Impulse 9 even though the Warp 13 has bad efficiency (albeit at diffe...
by coulomb
Wed, 18 Feb 2009, 04:30
Forum: Electric motors and controllers
Topic: AC or DC?
Replies: 99
Views: 16627

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. Oops....
by coulomb
Tue, 17 Feb 2009, 16:32
Forum: Electric motors and controllers
Topic: AC or DC?
Replies: 99
Views: 16627

AC or DC?

Do all DC motors contain brushes? I read here that brushes in DC motors are bad because they obviously wear out over time, but also because they produce ozone, cause heat loss, etc. This site makes AC motors look a much more efficient option than DC, and three phase AC looks even better still. Ther...
by coulomb
Tue, 17 Feb 2009, 05:42
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 80358

AC motors, multipoles, torque

Something tells me that three of the magnetic fields are reversed in the parallel Star Dahlander arrangement and this could cause the rotor to abruptly spin in reverse if these were switched while in motion... I believe that this is intentional. The fields are sized so that one subtracts from but d...