Search found 3641 matches

by coulomb
Wed, 11 Feb 2009, 06:39
Forum: Electric motors and controllers
Topic: Introductions & initial thoughts...
Replies: 16
Views: 2482

Introductions & initial thoughts...

So I recon you could pick up 2 x 4kW units and rewind them for less than one AC24LS. Or order the 220-240v delta option for the 7.5kW motor ("S" instead of "D" in the 13th code position for ABB motors). I imagine the uncommon option might cost a bit more than the default 380-415v model, but surely ...
by coulomb
Wed, 11 Feb 2009, 06:21
Forum: Electric motors and controllers
Topic: Introductions & initial thoughts...
Replies: 16
Views: 2482

Introductions & initial thoughts...

Here are the eqv(near) (to AC24LS): 4kW 4-pole 112frame (224mm dia) 30kg 26.4Nm Nominal To get 92Nm it needs a torque multiplier of 3.48 Also voltage set to 150V So would be 10.7kW nominal and 36kW peak. 7.5kW 2-pole 132frame 44kg 25Nm Nominal To get 92Nm it needs a torque multiplier of 3.68 Also v...
by coulomb
Tue, 10 Feb 2009, 17:10
Forum: Electric motors and controllers
Topic: AC or DC?
Replies: 99
Views: 12579

AC or DC?

I would think a 40AH 312v (104 cell) TS pack would satisfy your range requirements. at 12kw discharge rate, you have 12kwh avail. max power would only be around 50kw (at the batteries, 50-60hp at the wheels) What does this mean? http://forums.aeva.asn.au/smileys/smiley5.gif Especially the kw and kw...
by coulomb
Tue, 10 Feb 2009, 16:13
Forum: Electric motors and controllers
Topic: How Does Regeneration Work
Replies: 46
Views: 6049

How Does Regeneration Work

I'm almost there! Are you saying that by reducing the cyclic rate of the variable frequency drive to say 48.41 Hz, that the rotor in spinnning at say 1470 rpm, will try to slow down to 1455 rpm and produce a back emf (with current) that feeds backwards through the bypassing diodes to pull the rotor...
by coulomb
Tue, 10 Feb 2009, 02:42
Forum: Electric motors and controllers
Topic: How Does Regeneration Work
Replies: 46
Views: 6049

How Does Regeneration Work

As everything is starting to come together mentally, I am confused at how AC regeneration will work. Assuming that I have a variable frequency drive, and the vehicle is moving and I want to slow down, is it simply a matter of slowing down the drive frequency so that the motor moves into generator m...
by coulomb
Mon, 09 Feb 2009, 16:17
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 64113

AC motors, multipoles, torque

I have access to a Baldor M3313T Industrial AC motor configured for 1760 RPM at 60Hz. (possibly for free) I was wondering if I could use this for a EV motor. It's a 10HP motor, so ~7.5kW. That's a little small, but may be usable. It also seems to be dual voltage, i.e. one winding with up to 230v, a...
by coulomb
Mon, 09 Feb 2009, 06:23
Forum: Electric motors and controllers
Topic: AC or DC?
Replies: 99
Views: 12579

AC or DC?

However, Nutz has a point that with 180+ single cells to wire up and a BMS on each one, the overhead of lots of small cells does add up. So I'm tending towards a quite simple BMS board per cell, and something a bit smarter perhaps at the module level. Perhaps you only can measure voltage at the modu...
by coulomb
Mon, 09 Feb 2009, 06:12
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 108380

Home grown BMS ideas !

The diodes perform an essential task (IMHO) as they stop any backfeed from the battery module to charger caps ans also stop any fault condition of one cell / battery from draining any other modules that may be in parallel. Ok, good points. But I still think it may be better not to parallel all the ...
by coulomb
Mon, 09 Feb 2009, 05:03
Forum: Electric motors and controllers
Topic: AC or DC?
Replies: 99
Views: 12579

AC or DC?

"You could of course just use a 26kW 50Hz motor and a lower voltage, higher current inverter, but then the motor weighs a lot more,..." I don't understand. Surely the motor magnetic circuit would be the same but the winding turns would be less with thicker wire - (or parallelled thinner wire to fil...
by coulomb
Sun, 08 Feb 2009, 17:47
Forum: Electric motors and controllers
Topic: AC or DC?
Replies: 99
Views: 12579

AC or DC?

So let me see if i get this right, DC is cheap to build, but gives the performance of a golf cart. If I want any sort of street cred. I will need to go for a mid-large sized AC set up (gearbox optional) Close, but some of the hottest racing machines are still DC (e.g. John Wayland in the USA). At t...
by coulomb
Sun, 08 Feb 2009, 07:42
Forum: Electric motors and controllers
Topic: AC or DC?
Replies: 99
Views: 12579

AC or DC?

I am a bit puzzled why we need to have a higher voltage for AC motors. It has to do with the fact that industrial motors can generally stand around 415v ac (or a little more). You can get them at nominally lower voltages. For example, ABB motors have can be ordered with an "S" in position 13 of the...
by coulomb
Sat, 07 Feb 2009, 21:45
Forum: Batteries, charging, management and monitoring
Topic: 3 phase charging
Replies: 19
Views: 4164

3 phase charging

I assume most circa 1968 meters would be 3 phase mechanical? Certainly all 1968 vintage meters would be mechanical. The only 3 phase meter I've seen is a fair bit larger than the usual black keyhole-shaped single phase meters, and you can clearly see the three pieces of laminated iron each at 120 d...
by coulomb
Fri, 06 Feb 2009, 21:28
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 108380

Home grown BMS ideas !

Do chargers like being paralleled? An excellent question, and I'm not that sure. For bulk charging, they are essentially switch mode power supplies, and each of these has a slight droop with load. I guess that means that some of them might not provide as much current as others. In extreme cases whe...
by coulomb
Fri, 06 Feb 2009, 20:05
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 108380

Home grown BMS ideas !

Here is version 3 of my battery paralleling circuit; many thanks to acmotor for his many suggestions: http://forums.aeva.asn.au/uploads/689/switch_and_diodes_v3.png In this version, there is only one (set of) charger(s), so there is no possibility of a shock of two times the charger voltage. I've al...
by coulomb
Thu, 05 Feb 2009, 07:20
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 108380

Home grown BMS ideas !

So you have a one bus solution for the Rodeo? Ah, no, I'm guessing this is already done in Red Suzi, with this box: http://forums.aeva.asn.au/uploads/24/P1030773_inside_charging_box_compressed.JPG BTW, are the fuses in there? Or in the modules? http://forums.aeva.asn.au/smileys/smiley25.gif When yo...
by coulomb
Thu, 05 Feb 2009, 06:52
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 108380

Home grown BMS ideas !

Cut, paste and mirror has got the better of you ! Note diode A/K on positive charge bus. Oops! http://forums.aeva.asn.au/smileys/smiley9.gif    Corrected now, thanks. I would still not use any earth return, even though your were thinking charge current only. For two reasons.... Fault currents will ...
by coulomb
Wed, 04 Feb 2009, 06:58
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 108380

Home grown BMS ideas !

Can you re-draw with fuses at the diodes? http://forums.aeva.asn.au/uploads/689/switch_and_diodes_v2.png Edit: 2 right hand side diodes were wrong way around. Thanks, acmotor! I'm not sure whether to include the contactors inside each battery group, or leave them, as shown, between groups. I'd also...
by coulomb
Wed, 04 Feb 2009, 05:49
Forum: Batteries, charging, management and monitoring
Topic: Power Consumption for Dummies
Replies: 144
Views: 15912

Power Consumption for Dummies

coulomb ...so how is the parallel not cancellin out power as they are connected negative to negative in the begining or positive to positive at the end? The difference is in a series string with negative connected to negative, you are measuring/using two positive leads, so the total voltage is zero...
by coulomb
Wed, 04 Feb 2009, 05:23
Forum: General EV Discussion
Topic: Green Car Innovation Fund
Replies: 57
Views: 4369

Green Car Innovation Fund

Mark T wrote:Was the light plane guy Howie Hughes with his Roadie EV ?
He started by saying that his name always gets a laugh. "My name is Howard Hughes and I produce aircraft". So yes, it sounds like it.
by coulomb
Tue, 03 Feb 2009, 18:39
Forum: General EV Discussion
Topic: Green Car Innovation Fund
Replies: 57
Views: 4369

Green Car Innovation Fund

Ok, I've been yesterday to the Brisbane session. Here are my thoughts: 1) This is not for the very small company or individual that has little money behind him/her. The usual ratio is 1:3 (1 government grant dollar to 3 grantee dollars, and you have to prove that you have your $3). The minimum grant...
by coulomb
Tue, 03 Feb 2009, 18:06
Forum: Batteries, charging, management and monitoring
Topic: Power Consumption for Dummies
Replies: 144
Views: 15912

Power Consumption for Dummies

another question....putting cells in series and in parallel..in regards to making the volts and getting the right amps how does this work? can you explain this to me. I'll have a go at this one. First, let's consider series: http://forums.aeva.asn.au/uploads/689/series.png The two parallel bars rep...
by coulomb
Mon, 02 Feb 2009, 16:01
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 108380

Home grown BMS ideas !

Never use earth return for traction pack currents. It is not safe and you risk super-imposing voltage on the 12V aux system. Run a separate wire. I don't suggest this; only charging current. Traction current will use the ends of the batteries (+350 and -350 wrt chassis). Can you re-draw with fuses ...
by coulomb
Mon, 02 Feb 2009, 03:58
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 108380

Home grown BMS ideas !

If the pack fuses are put in series with the battery connections to ground, then at least any contactor problems like make before break or a flashover will be safe. (In the sense that blowing a multi-hundred amp fuse is ever "safe" http://forums.aeva.asn.au/smileys/smiley3.gif )   Of course, that le...
by coulomb
Mon, 02 Feb 2009, 02:35
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 108380

Home grown BMS ideas !

I suppose we could invert the negative batteries and put the whole lot in parallel. No need for paired chargers, either. Hmmm. Next post perhaps. Oops, the negative side doesn't "invert" quite so easily. So this arrangement might have to be confined to conversions where the positive and negative pa...
by coulomb
Mon, 02 Feb 2009, 02:23
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 108380

Home grown BMS ideas !

Coulomb, keep thinking about the parallel charging of modules though. Add in some diodes in the charging lines. It would be intersting to see if you come up with something similar to my (yet to be posted !) circuit. Ah, I think you might mean something like this: http://forums.aeva.asn.au/uploads/6...