Search found 121 matches

by T2
Mon, 09 Sep 2013, 09:22
Forum: Electric motors and controllers
Topic: Junkyard motors parade
Replies: 130
Views: 23624

Junkyard motors parade

Since I may embark on the rewinding of a 5.5kw soon with plans to include an integral 4 :1 planetary reducer later on, I continue to follow your progress with interest. I will be considering a stationary Back-to-Back test rig with facility for testing at nominal powers and perhaps greater. The most ...
by T2
Tue, 27 Aug 2013, 12:38
Forum: Electric motors and controllers
Topic: Junkyard motors parade
Replies: 130
Views: 23624

Junkyard motors parade

Thank you for jumping in with that post, BigMouse, a useful contribution if I may say. Hi Peskanov, I was going to put up another post as well but I am starting to see a new problem develop here - maybe YOU are getting TOO much advice. It's keeping you away from the task in hand, which was not my no...
by T2
Sun, 25 Aug 2013, 08:20
Forum: Electric motors and controllers
Topic: Junkyard motors parade
Replies: 130
Views: 23624

Junkyard motors parade

It's interesting to read about your efforts, but why would you be winding a motor as 2-pole when it is to be used with a VFD? Unless I am misguided Weber, it appears to be a four pole using the "consequent pole" technique. I would like to elaborate on your statement equivalent to a gear-change in y...
by T2
Fri, 23 Aug 2013, 23:04
Forum: Electric motors and controllers
Topic: Junkyard motors parade
Replies: 130
Views: 23624

Junkyard motors parade

Peskanov you wrote : The problem I see using lower voltages is that I lose the maximum torque (capability) of the motor. The specs of this motor (well, the closest ones I found) say Tm/Tn=3.1 This a minimum of 3x nominal amps, surely bigger because of heavy losses at high slip. If nominal is 230A (y...
by T2
Fri, 23 Aug 2013, 15:51
Forum: Electric motors and controllers
Topic: Junkyard motors parade
Replies: 130
Views: 23624

Junkyard motors parade

Yes, I prefer the WYE connection for two reasons. First, the phase windings and their magnetic circuits must be almost identical for all three phases otherwise with the mesh (delta) connection there could be circulating currents around the mesh that could cause unnecessary heating of the stator wind...
by T2
Sun, 18 Aug 2013, 23:42
Forum: Electric motors and controllers
Topic: Junkyard motors parade
Replies: 130
Views: 23624

Junkyard motors parade

Peskanov, you wrote If I use 2 turns instead of the original 14, I get 230/7=32.8V & 400/7=57.1V, two nice voltages for playing with the Curtis. 56 wires / 2 turns = 28 wires in hand. I guess that makes 0.65V/Hz & 1.14V/Hz, right? Let's take a look. 56 wires 4-in-hand = 14 turns = 400Vac in WYE conn...
by T2
Thu, 25 Jul 2013, 12:46
Forum: Electric motors and controllers
Topic: Torque Vectoring or Traction Control - Twin motors
Replies: 32
Views: 3916

Torque Vectoring or Traction Control - Twin motors

Hi Crash,      Yes motor torque, power and weight are approximately the same however the total torque at the wheels is not and that is despite the fact of Tesla roadster having only one motor compared to four on the E-tron. The problem is that the maximum rpm of induction motors of this size are lim...
by T2
Wed, 24 Jul 2013, 10:38
Forum: Electric motors and controllers
Topic: Torque Vectoring or Traction Control - Twin motors
Replies: 32
Views: 3916

Torque Vectoring or Traction Control - Twin motors

The Audi R8 e-tron does 0-60mph in 4.8secs which is quite a bit slower than the Tesla cars which can do 3.9secs. How come ? It has to be in the gear ratio. The Tesla's Vmax is 120mph. For the E-tron it must be about 160mph. There is an excellent Youtube video posted of the E-tron earlier this year r...
by T2
Tue, 23 Jul 2013, 23:34
Forum: Electric motors and controllers
Topic: AC electric motor rewinding for EV use
Replies: 98
Views: 21405

AC electric motor rewinding for EV use

I say that rewinding IPM Prius machines deserves its own thread..
by T2
Mon, 22 Jul 2013, 16:02
Forum: Electric motors and controllers
Topic: Junkyard motors parade
Replies: 130
Views: 23624

Junkyard motors parade

I am glad you have taken up the idea of downsizing to a 5.5Kw. You expressed anxiety over the reduced efficiency expectations with smaller motors, but aren't those specifications based on 50/60Hz operation and outside of the higher rpms of automotive usage ? Tests reported here three years ago (AEVA...
by T2
Sat, 20 Jul 2013, 11:29
Forum: Electric motors and controllers
Topic: Junkyard motors parade
Replies: 130
Views: 23624

Junkyard motors parade

About the gear ratio: I plan to keep original transmission & gears, I think I will need them to get the most of this controller. I would point out one thing, something I think Richo would agree with also, is that the 7.5Kw frame size is too large. Going forward with a low voltage rewind would trans...
by T2
Fri, 19 Jul 2013, 07:45
Forum: Electric motors and controllers
Topic: Junkyard motors parade
Replies: 130
Views: 23624

Junkyard motors parade

-peskanov you wrote That's a 2.5x torque, pretty common for ACIMs, right? Yes sure. I don't understand why do you say I am limited to nominal torque It's just that when discussing the rewind, I had expected you would prefer discussion with nominal values only, since the replacement wire must be capa...
by T2
Thu, 18 Jul 2013, 11:49
Forum: Electric motors and controllers
Topic: Junkyard motors parade
Replies: 130
Views: 23624

Junkyard motors parade

BTW, Peskanov, thanks for this thread. I know, chances are, most of the time you are positioned to be on the receiving end of unintended brickbats rather than bouquets ! I have been finding the images from your motor teardown to be both interesting and instructive. The story so far. We know the moto...
by T2
Wed, 17 Jul 2013, 17:14
Forum: Electric motors and controllers
Topic: Junkyard motors parade
Replies: 130
Views: 23624

Junkyard motors parade

Peskanov, on July 5th you wrote To be fair, "2 pole motors have more back iron" is an ambiguous sentence. On Pg 2 "14000rpm Machines" thread there is a post from Weber dated Oct 12th 2012 depicting data from the ABB motor catalog Dec 2010. Observe 131-002, 132-002   7,5Kw 2 and 4 pole resp. Observe ...
by T2
Sat, 13 Jul 2013, 03:04
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 8419

14000 rpm Machines

300A switching device, but peak bus current is only 225A ? -Matt but this device is mounted on an air cooled heat sink ? Since I am not aware of your level of expertise in switchmode design, I would tentatively suggest that this 225 Amp limitation is to do with the ON state losses in the device. Ty...
by T2
Thu, 11 Jul 2013, 18:32
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 8419

14000 rpm Machines

Maybe the lead acid pack couldn't take that sort of power, or would have led to a lower life I agree, back in 88/89 lead acid was the only choice but at least they were more enduring than those of today. Going larger than TO-247 style you could get 500V mosfets with Ids of 44A or if you wanted 200A...
by T2
Thu, 11 Jul 2013, 14:14
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 8419

14000 rpm Machines

Don't forget you still need RPM overhead past the peak. I envisage peak being a standard 60mph since this is a recognised performance benchmark. Constant Power from there to 110km/Hr or 70mph should be sufficient for manoeuvering into the center lane for cruising and keeping clear of heavy vehicles...
by T2
Thu, 11 Jul 2013, 10:51
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 8419

14000 rpm Machines

In order to get more revs and therefore even more power the V/Hz must be lowered by a factor of 10 times at least from the original values. So a 4-pole typically 1,500RPM is now 15,000RPM. Richo - not exactly. First the V/Hz has to be reduced just so as to place the inverter bus voltage within a rea...
by T2
Tue, 09 Jul 2013, 15:39
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 8419

14000 rpm Machines

What I am trying to focus on in this thread is with the motor itself. Clearly the preponderance of direct drives shows that the operation of the electric motor is not understood as well as it could be. Generally the electric motor is not appreciated from the angle that it is a magnetic device. In th...
by T2
Thu, 06 Jun 2013, 09:34
Forum: Electric motors and controllers
Topic: ABB reluctante motor
Replies: 57
Views: 6877

ABB reluctante motor

Peskanov, I didn't follow much in the link - it's almost 50yrs since I last used partial derivatives - and I didn't stay for an MSc either on account of they kicked me out !! Nevertheless I have to query an Iraqui student with an Indian examiner at a Swedish technical institute copying Korean resear...
by T2
Wed, 05 Jun 2013, 06:34
Forum: Batteries, charging, management and monitoring
Topic: Replacing a dead cell
Replies: 15
Views: 1532

Replacing a dead cell

My own experience is this. Unless you determine the longevity of the remaining battery this could be the start of "death by a thousand cuts". My advice is that you bypass temporarily the bad cell. This will allow you to drive the vehicle with at least 90% of its performance in order to determine whe...
by T2
Sat, 18 May 2013, 08:43
Forum: Electric motors and controllers
Topic: Siemens 1PV5138-4WS24
Replies: 43
Views: 6389

Siemens 1PV5138-4WS24

Too Qik wrote my preference is not to be playing with drive ratios to get the torque figures I want. This is the major mistake most amateur constructors make. The better strategy is to think of the gear box as a way to make the outside world look easier to the powertrain. Use of an additional singl...
by T2
Fri, 10 May 2013, 15:00
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 8419

14000 rpm Machines

mizlplix has started a thread on the practice of rewinding entitled "AC electric motor rewinding for EV use" . Originally I composed this to go on that thread however I want to provide some jottings here to avoid possibly disrupting that thread. For the same reason I don't post on www.ivanbennett.co...
by T2
Tue, 07 May 2013, 12:42
Forum: Electric motors and controllers
Topic: AC electric motor rewinding for EV use
Replies: 98
Views: 21405

AC electric motor rewinding for EV use

Hi Miz , nice work. On your site I noticed that you had chosen a 2-pole as a candidate for a rewind. AEVA is probably a more neutral site for advising against the re-use of 2- pole machines. This exact idea has been discussed here just recently. I wrote the following on 2nd OCT 2012 on the "14000rpm...
by T2
Tue, 23 Oct 2012, 13:13
Forum: Electric motors and controllers
Topic: 14000 rpm Machines
Replies: 53
Views: 8419

14000 rpm Machines

Apparently you haven't inspected the chart closely enough. It shows a decrease in specific torque from 4-pole to 6-pole in sizes smaller than 132-frame but an increase in specific torque from 4-pole to 6-pole in sizes larger than 132-frame. The bigger they get, the better 6-poles look. If you were ...