Search found 2624 matches

by weber
Mon, 23 Mar 2009, 21:59
Forum: Technical and conversion discussion
Topic: NCOP14 regulations, safety and revision
Replies: 143
Views: 15535

NCOP14 regulations, safety and revision

weber, I follow you on all that but still have reservation about a demonstrated leakage detection for EVs not appearing yet and the mindset that floating makes it safe when all the other good practice of insulation has been left out ! e.g. most EVs at present. Are people doing greater than 144 Vdc ...
by weber
Mon, 23 Mar 2009, 20:02
Forum: Members Machines
Topic: Weber and Coulomb's MX-5
Replies: 1698
Views: 341884

Weber and Coulomb's MX-5

The MX-5 fuel tank is the most ridiculous and asymmetrical and complicated shape you ever saw. I've seen toads that look nicer. That photo doesn't show the half of it. It's as if they blew up a balloon in the only space that was left, then had that shape made out of steel. At the back there's an ind...
by weber
Mon, 23 Mar 2009, 18:42
Forum: Technical and conversion discussion
Topic: NCOP14 regulations, safety and revision
Replies: 143
Views: 15535

NCOP14 regulations, safety and revision

I'm considering systems with a total battery voltage greater than 240 Vdc here as in our own industrial AC conversions. weber, Just thinking about it, a floating system that only sounds an alarm and does not disconnect the pack, in fact break it up into safe voltage modules, is in itself no more saf...
by weber
Mon, 23 Mar 2009, 16:06
Forum: Members Machines
Topic: Toyota Corolla Conversion
Replies: 128
Views: 21091

Toyota Corolla Conversion

lachlanmac wrote: My mechanic friend cunningly removed the old clutch lever boot and looked in. He could see that the flexible coupling between the motor and the transmission was beginning to come apart

Hi lachlanmac, can you please tell us what kind of flexible coupling you used.
by weber
Mon, 23 Mar 2009, 05:40
Forum: Technical and conversion discussion
Topic: NCOP14 regulations, safety and revision
Replies: 143
Views: 15535

NCOP14 regulations, safety and revision

acmotor, I plead guilty to ignoring parts of AS 3000 and insisting on others. i.e AS 3000 clearly says isolated (floating) supplies cannot exceed 500 V. So let me now look seriously at the center earthed option. For that to be as safe, in regard to electric shock and fire, as the floating option hav...
by weber
Mon, 23 Mar 2009, 04:54
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68662

AC motors, multipoles, torque

Hmmm, all the controllers I've looked at (Danfoss, Telemecanique, Lenze) have power ratings which cut in (do they cut in or are the ratings just approximate based on current limits ?) before this part of the curve is reached. Hi woody, I would expect the VF drive's self-protective limits (as oppose...
by weber
Sun, 22 Mar 2009, 18:00
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68662

AC motors, multipoles, torque

Sadly, I would have written much the same as Tritium_James re the boost converter. The cheapest way to make such a high powered one might be to modify an existing VF drive and add some inductors, but it's hard enough to fit one VF drive in a vehicle, let alone two. Developing a new switching convert...
by weber
Fri, 20 Mar 2009, 23:04
Forum: Technical and conversion discussion
Topic: NCOP14 regulations, safety and revision
Replies: 143
Views: 15535

NCOP14 regulations, safety and revision

I don't doubt you on any of that, lithbattboss. I'm just hoping to delay that inevitable loss of freedom, by educating and encouraging more voluntary responsibility. To that end, I hope you would educate anyone who wanted to buy a 144 V module off you, and suggest they buy two 72 V modules instead.
by weber
Fri, 20 Mar 2009, 20:55
Forum: Technical and conversion discussion
Topic: NCOP14 regulations, safety and revision
Replies: 143
Views: 15535

NCOP14 regulations, safety and revision

so if they were installed in a building you could break them down into smaller modules using tools anyway... Not without voiding your warranty. Correct me if I'm wrong, lithbattboss. Sure, AS 3011 doesn't apply to EVs, but I note that battery enclosures in buildings aren't often involved in collisi...
by weber
Fri, 20 Mar 2009, 17:45
Forum: General EV Discussion
Topic: recharge points long term view
Replies: 37
Views: 3876

recharge points long term view

Is there a 32A single phase outlet? http://forums.aeva.asn.au/smileys/smiley1.gif or aren't those the ones that look like a 3 phase plug? Weeell, I was going on what coulomb found here. http://en.wikipedia.org/wiki/AC_power_plugs_and_sockets#Type_I But now that I go looking for these mythical beast...
by weber
Fri, 20 Mar 2009, 16:44
Forum: Technical and conversion discussion
Topic: NCOP14 regulations, safety and revision
Replies: 143
Views: 15535

NCOP14 regulations, safety and revision

Lithbattboss pointed out, quite correctly, that there is no requirement for LV UPS batteries to be broken up into ELV segments I was mistaken, and so was lithbattboss. There _is_ a requirement. It's in AS 3011 "Secondary batteries installed in buildings". It must be possible to break them up into 1...
by weber
Fri, 20 Mar 2009, 16:27
Forum: General EV Discussion
Topic: recharge points long term view
Replies: 37
Views: 3876

recharge points long term view

Did I miss some consensus on what kind of outlet we want. A really fast charge needs 3-phase 415 Vac, but the charger is probably to big to carry around. A 32 amp single-phase socket would be nice. You can plug all smaller current ratings into it.
by weber
Fri, 13 Mar 2009, 09:27
Forum: Electric motors and controllers
Topic: AC motor big words
Replies: 16
Views: 2510

AC motor big words

you cant get away with a smaller vfd, as you need the higher motor side amps, to drive the bigger motor, to get the higher torque needed to get the same power at lower rpm. But at lower rpm, you have some volts to spare, so you trade them for reduced amps by switching your motor from delta to star....
by weber
Fri, 13 Mar 2009, 08:44
Forum: Electric motors and controllers
Topic: AC motor big words
Replies: 16
Views: 2510

AC motor big words

A gearbox helps reduce the peak power requirements. For example using about 85kW peak motor will get a BMW to 100 under 8 secs using a gear box. Using the motor direct drive it would be about 15 seconds (Slower than the original car). To achive the same results without the gearbox I need more like ...
by weber
Tue, 10 Mar 2009, 22:31
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 14937

Electric Beemer

Richo wrote:Wow 10 DegC that's nice even for an extreme case. Image

I worry that I've lost a zero or a decimal place somewhere. I'd appreciate an independent check.
by weber
Tue, 10 Mar 2009, 22:17
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 14937

Electric Beemer

Thanks woody and acmotor. It should be pointed out that the rule that says DC current is sqrt(3/2) times power factor times AC current, only applies when the 3-phase VF drive is putting out its maximum sine wave (between phases). If it's running at a speed well below the motor's field-weakening poin...
by weber
Tue, 10 Mar 2009, 21:07
Forum: Technical and conversion discussion
Topic: HV in conduit or not? or what?
Replies: 16
Views: 2785

HV in conduit or not? or what?

Go to Bunnings (etc) and ask in the building supplies section, for a steel top-hat ceiling batten. This is about 40 mm wide and about 25 mm high and comes in a 6.1 metre length. It's coated in zinc-alume and then blue anti-glare. I get the staff to cut it in half with their aviation-snips so I can f...
by weber
Tue, 10 Mar 2009, 20:06
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 14937

Electric Beemer

Woody if you want to know the Voltage of the pack at a given power level: Vc = Nominal voltage of cell (V) ie 3.2V P = Power used by system (kW) ie 100kW Ns = Number of strings of batteries you have in parallel ie 1,2,3. Cs = Number of cells in a string ie 220 Rc = Impedance of cell in MilliOhms (m...
by weber
Tue, 10 Mar 2009, 17:10
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 14937

Electric Beemer

So in summary, to supply the equivalent of 400V AC of 100 amps AC per 3 phases at unity power factor (e.g. plug a VFD into a wall), I need to supply sqrt(3) * 100 = 173 Amps of DC @ sqrt(2) * 400V = 565V No. As TJ said, You need to supply sqrt(3)/sqrt(2) * 100 A = 122 A. And the voltage will need t...
by weber
Tue, 10 Mar 2009, 05:09
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 14937

Electric Beemer

I think: drawing current from the batteries reduces the voltage. At some point this reaches a power peak. I don't think we can make the AC controllers aim for this peak. No! It happens when the load resistance equals the internal resistance of the battery and so it occurs at half the battery open-c...
by weber
Tue, 10 Mar 2009, 00:28
Forum: Technical and conversion discussion
Topic: trip meter / charge remaining
Replies: 16
Views: 2178

trip meter / charge remaining

In AS/NZS 3000:2007, section 7.4 deals with "ELECTRICAL SEPARATION (ISOLATED SUPPLY)". I see nothing in that section that would limit SLV to 500 V. Oops! I see it now. Section 7.4.3(a). But doesn't that mean we have to have a _solid_ earth (connection to chassis) at the center point? I have continu...
by weber
Tue, 10 Mar 2009, 00:19
Forum: Technical and conversion discussion
Topic: NCOP14 regulations, safety and revision
Replies: 143
Views: 15535

NCOP14 regulations, safety and revision

There is an Australian Standard, AS/NZS 5033:2005 "Installation of photovoltaic (PV) arrays", that must deal with low voltage (LV) DC sources (where "low voltage" means greater than 120 V dc and less than 1500 V dc). It applies to PV arrays with DC voltages up to 600 V between positive and negative ...
by weber
Mon, 09 Mar 2009, 20:42
Forum: Technical and conversion discussion
Topic: trip meter / charge remaining
Replies: 16
Views: 2178

trip meter / charge remaining

Hi acmotor, I think we'd need a very good reason _not_ to comply with AS 3000. AS 3000 is a well honed document designed to protect life and property. We are having an unregulated honeymoon period with EVs now, similar to what PV power systems had a decade ago. The first time someone's EV causes ser...
by weber
Sun, 08 Mar 2009, 19:43
Forum: Technical and conversion discussion
Topic: trip meter / charge remaining
Replies: 16
Views: 2178

trip meter / charge remaining

no , but we need to look at whether we want to detect short circuit or fault in the 3 ph side only , or also the DC battery side obviously in a 3 phase high voltage system its priority , just need to check the operating voltage range for the ELCB i have fitted them to 3Ph Gensets .. $ 30 is cheap I...
by weber
Sun, 08 Mar 2009, 18:51
Forum: Electric motors and controllers
Topic: adding a 'sort of' turbo
Replies: 17
Views: 2488

adding a 'sort of' turbo

your probably thinking of nitrous oxide, which isnt actually flammable either, but decomposes at high temperature into nitrogen and oxygen reason its used in drag racers is because on the compression stroke, the decomposing nitrous oxide absorbs some of the heat, meaning you can cram more fuel into...