Search found 121 matches

by T2
Tue, 23 Oct 2012, 08:08
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 10076

14000 rpm Machines

I assume you to mean these to be driven at the same electrical frequency and so it is the 2-pole that is rotating at double the speed of the 4-pole. In that case the materials are being "used" equally frequently, and I don't understand why the 2-pole would even seem to be using them twice as freque...
by T2
Wed, 17 Oct 2012, 13:05
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 10076

14000 rpm Machines

             The Case for the Two Pole Motor -Weber 4-poles have nearly twice the peak torque of same-frame-size similar-mass 2-poles. I am asking the question should 2-pole machines be eliminated as candidates for EV powertrains ? Although I haven't actually performed a side-by-side physical teard...
by T2
Tue, 02 Oct 2012, 12:49
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 10076

14000 rpm Machines

you must also hold the pole count constant for the above to be true. Weber, I'm coming around to your style of thinking. The windlass is a good allegory for the multipole effect - I'm still looking for a magnetic solution that explains to my satisfaction. My experience is that I noticed 2 poles are...
by T2
Mon, 01 Oct 2012, 22:08
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 10076

14000 rpm Machines

I have heard that a front wheel drive transmission is more efficient than a rear wheel drive, and that losses amount to about 17% from flywheel to drive wheel in a FWD. Possibly closer to 23% in a RWD car. I have first hand dyno experience with that using my field controller where a VW rear transax...
by T2
Fri, 28 Sep 2012, 07:44
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 10076

14000 rpm Machines

                      We Don't Need No Stinkin' Efficiency !! I have seen EVers describe the system they are going to build to be the very model of efficiency then have something like a toothed belt to the final gear or an automatic transmission. That something which totally negates all the care ta...
by T2
Fri, 28 Sep 2012, 06:24
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 10076

14000 rpm Machines

   Richo, have you any data to support rotor integrity problems at high rpm ? The images I have seen show aluminum rotor bars "seeping" through rotor slots or surface wear patterns that were likely preceded by a partial bearing collapse. These were all on large diameter rotors I would say 250HP and...
by T2
Thu, 27 Sep 2012, 14:55
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 10076

14000 rpm Machines

Richo, The general answer to your question is to have the rotor balanced when you take the stator in to be rewound as ACMOTOR did for Red Suzi. In this case the balance before adjustment was found to be -650gm.mm Following adjustment this was brought down to 30gm.mm @ 6000 rpm Considering this 24Kg...
by T2
Wed, 29 Aug 2012, 12:00
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

So T2, we see it is the increased frequency, not the increased rpm, that gives us more power from the same size motor. Eurodrive       2Hp 3600rpm 47lbs       2hp 1800rpm 47lbs With the DRE90L2 and DRE90L4 frame sizes resp. (1E2 effcy rating) Explanation they just reversed one pole to wipe out the ...
by T2
Wed, 29 Aug 2012, 09:37
Forum: Electric motors and controllers
Topic: RX400H transaxle
Replies: 169
Views: 27085

RX400H transaxle

So I've been pecking around Evo-electrics website. Heck, they don't give you a lot of info to go on. Unless you decide to use 600Vdc there is no torque graph to give guidance on motor performance, that's if you had decided to use a less stratospheric voltage like 320Vdc and would be curious as to ho...
by T2
Sat, 18 Aug 2012, 13:39
Forum: Electric motors and controllers
Topic: 3-phase IM DTC controller build
Replies: 92
Views: 13203

3-phase IM DTC controller build

I would like to raise something I find disturbing about the ECICaps whitepaper since no-one has brought it up. Formula (29) delta V =Vbus/(32*L*C*f^2) is used to calculate the needed capacitance of a film cap capacitor bank without regard for the existing phase current. I had hoped someone would bri...
by T2
Thu, 09 Aug 2012, 11:36
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

-woody I don't think there is a consistent data set out there. For starters I am sure that manufacturers haven't made every single motor size shown in their catalogues. Since the same frame size can house a range of stators with different stack lengths I suspect the figures in the catalogues are for...
by T2
Tue, 07 Aug 2012, 16:21
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 10076

14000 rpm Machines

This is a topic for those who have an interest in high speed electrical machines and the gearing systems designed to accept them. The machine of interest here is going to be the induction motor,. That being so what is so wrong with PMSMs ? There is no denying that permanent magnet synchronous motor...
by T2
Tue, 07 Aug 2012, 09:25
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

- weber I say torque/mass ratio increases significantly (but not quite linearly) with pole count. You say it shouldn't increase at all. So why haven't you given the respective torques or torque/mass ratios for these motors, so we can see which claim is supported? 4-pole 519lbs   286 frame 6-pole 689...
by T2
Tue, 07 Aug 2012, 07:26
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

I think I can ignore peak anything and stick with constant ratings Even if it calls for peaks of 120 kW on occasion, I will know that the motor will be able to handle it. So at 4000 rpm graph shows 180N-m for the AFM-140-4 with a Kt of 1.81N-m/Amp which infers a current limit of 100Amps, a 7C rate ...
by T2
Mon, 06 Aug 2012, 19:12
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

-jonescg Yes, good idea to separately cool the inverter. You haven't revealed your battery pack details. I estimate 200 LiPo cells and climbing . Do you have a BMS ? While racing how do you propose to keep an eye on that many cells ? I am wasting my time here. The supplied graphs are all very well b...
by T2
Sun, 05 Aug 2012, 11:18
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

-jonescg if you have decided on 600Vdc and the AFM-140-4 then it would appear that you have restricted your rpm range to 4000rpm. I therefore assume a multi-ratio gearbox is in use. In which case I have to ask why you didn't spring for the AFM-140-3 which gives you 5000rpm reach. Then make the 20% c...
by T2
Sun, 05 Aug 2012, 09:26
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

- weber I would debate you on multipolar machines but I have nothing to bring to the party. Although I did peruse Marathon's Premium Efficiency range. At random I selected 30Hp size regarding torque /mass correlation. 2-pole 499lbs   286 frame Probably some slots are left empty 4-pole 519lbs   286 f...
by T2
Sat, 04 Aug 2012, 11:34
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

Jonescg let me try to explain what is going on here. i have explained something which you don't understand. You have therefore tried denial So, T2, what you are saying is, Evo, who build and service high-powered axial flux permanent magnet AC motors, don't know what they are talking about Then you t...
by T2
Fri, 03 Aug 2012, 01:55
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

-Stiive, do you see the third paragraph from EVO's reply to jonescg ? you could employ a AF-140-5 machine, which will still spin up to 5000rpm provided the voltage is at least 600Vdc! It will have a lower power output than the AF-140-4, though, since the base speed where field weakening starts is lo...
by T2
Thu, 02 Aug 2012, 14:41
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

So ah, yeah. I'll be going with the 140-4 wound motor, driven by a PM150DZ inverter So which winding is that ? EVO site was down on the weekend so was AEVA and the following post got lost. WDG #3 11.79 rpm/volt   i.e. Lo V/Hz What jonescg wants WDG #4   8.842 rpm/volt   i.e. Hi V/Hz What EVO recomm...
by T2
Sat, 28 Jul 2012, 15:30
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

-weber, the first part of your statement said : It isn't more rpm as such that is required for getting more power out of a motor of a given mass, it is higher frequency. Nope, I have to disagree. But I thought you were on the same page with me earlier that for any given frame size its nominal torque...
by T2
Thu, 26 Jul 2012, 11:31
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

-jonescg I looked at the Agni website. They are quite informative but somewhat short on electrical drawings. They entitle product lines "The 95R Series Motor". Uh HUH but does that actully mean that it's a "series motor" ? Eventually I found a picture which shows only two motor terminals. Finally I ...
by T2
Thu, 26 Jul 2012, 05:41
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

-Richo         Yes, at 13krpm your motor would be capable of a nominal 35Kw That would be with a V/Hz that can support that rpm without field weakening which you want to avoid with a racing machine.    Original 4-pole/phase induction motor rated at 4Kw @1500rpm 50Hz Ambient temp 40deg c, with 80 deg...
by T2
Sun, 22 Jul 2012, 16:41
Forum: Electric motors and controllers
Topic: Getting the right windings...
Replies: 77
Views: 12298

Getting the right windings...

High currents = heat and heat is bad news First there is nothing wrong with higher currents with appropriate sized cabling and terminations. Plus who is to say that fewer larger terminals are more problematic than a plenitude of smaller ones ? Second if we consider even a 96V-120Vdc system and 550A...
by T2
Sun, 22 Jul 2012, 15:09
Forum: The Lounge
Topic: Carbon Tax on Green Energy
Replies: 29
Views: 4401

Carbon Tax on Green Energy

Feed In Tarriffs (FIT) for PV is 58cents/Kwhr here, it used to be 82cents. This when the spot price on wholesale market for hydro and thermally generated power was 4 cents, or when resold to the residential market it appeared as 7cents. Of course when the Province of Ontario realised they were losin...