ABB reluctante motor

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Richo
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ABB reluctante motor

Post by Richo »

I just noticed the 17kW in 160-Frame.
That's a bit of an oddity.
I don't see an application requiring 1 less kW and an extra 41kg Image

Even if you did use the 18.5kW 4-pole 400Vac@1500RPM.
That is still 55.5kW peak @3000RPM 400Vac (with rewind...)
To me that sounds like a micro to small car.

However because it's in a 132 frame I guess it could still be connected to a gearbox.
This is similar torque to a non-turbo'ed 2L engine.

So the short answer is NO but the long answer is YES.
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woody
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ABB reluctante motor

Post by woody »

The industrial ratings are all about nominal torque/power and efficiency at that point.
Cars seldom sit on the same power for very long, exception being driving across the nullabor.
Even on the freeway it's seldom flat (you notice in a 50 year old 32kW beast).

Peak power is important - you use it on occasion (or a lot if it's not very high). If you need 15kW to move on the flat at 110kph, you need more than that to get there, and and moving a 1 tonne car at 110kph up a 1 in 15 slope is another 20kW if my maths is close (110kph = 30m/s ; 1 in 15 = 2m/s rise; 9.8N * 1000kg * 2 = 20kW)

The power curve of an induction motor is not flat.

As for efficiency at over nominal torque, I think it gets as bad as 70% according to the maths I've seen, unless you are using some torque boost mode and over-magnetising the motor (which is OK in my book). And of course at stall / zero rpm the motor has the same efficiency as all other stationary motors - 0%.
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peskanov
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ABB reluctante motor

Post by peskanov »

Richo,
the 160 frames are all iron.
They have split the motors into 2 families, "industrial" and "for machine builders". Industrial start at frame 160, iron.
The smaller ones ("machine builders") are all aluminium. Maybe these are more expensive.

I used the 2 pole as reference, as the seem to offer same nominal & max torque than 4 poles, but at least good rotor balance at 3000 rpm is guaranteed.
I don't know how much can you rev a motor like that (reluctance motors are famous for high revs capability). The datasheet mention 3800 max, but I guess that is conservative.

If you can rev these motors to 4500 rpm and push torque to 1.5 nominal, you get 80KW, in the range of similar sized ACIMs (pushed much farther from nominal values)…and still have high efficiency.

Woody,
yep, in a car power will change a lot. That's the beauty of PM and reluctance motors, efficiency is very high in all the range.
ACIM eff. suffer a bit in low torque and low revs, even with a good vectorial controller.
I think you can get similar PM motors in this price range, but I dislike neodymium use a lot. I think EV design should move to sustainable models, and rare earths are completely unnecessary.

I understand peak power is important, I just wanted to point that for a similar weight, both ACIM and those SynRM motors seem to have similar max power. That's what my number tell, at least.

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Johny
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ABB reluctante motor

Post by Johny »

I should qualify my earlier remarks - perhaps change them.
I really meant to say that high peak torque is important - not so much peak power.
I am also coming from a direct drive perspective in these comments.
I am limited by my controller to about twice nominal torque at the moment and I use maximum available torque a few times a day when starting from standstill.
Efficiency wise - in a half hour commute I would exceed nominal motor power for perhaps 30 seconds all up so it doesn't rate high on my list. Half nominal rated power up to nominal rated power is where my EV motor spends most of its time.


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Richo
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ABB reluctante motor

Post by Richo »

peskanov wrote: I used the 2 pole as reference, as the seem to offer same nominal & max torque than 4 poles, but at least good rotor balance at 3000 rpm is guaranteed.

True - so you could use the 37kW stock 2-pole motor on a 400Vac conversion.
peskanov wrote: I don't know how much can you rev a motor like that (reluctance motors are famous for high revs capability).
The datasheet mention 3800 max, but I guess that is conservative.

Even 3800 would be ok.
peskanov wrote: If you can rev these motors to 4500 rpm and push torque to 1.5 nominal, you get 80KW, in the range of similar sized ACIMs (pushed much farther from nominal values)…and still have high efficiency.

I don't think it is really required.
My daily drive is 1000kg 1.6L 87kW.
But to get 87kW I would have to floor it and have an RPM over 5000RPM.
So I suspect I rarely would ever use more than this motors 55kW peak.
As I mentioned before I think it would be suitable as is for cars using up to a 2 litre motor - but still using the gearbox.

So the short answer is NO but the long answer is YES.
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peskanov
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ABB reluctante motor

Post by peskanov »

Johny,
if you are restricted to an existing drivetrain, sure, I agree. However, I think it would be a competitive motor using an extra reductor, as power rules over torque.

For direct drive without any extra gearing you need either a torque monster or strongly overdriving an small ACIM motor (ineffcicient). I guess that leaves you with DC motors, multipole PM motors, and very heavy ACIM.

I think SynRM shows some promise for direct drive (using reductor), if they can been revved up to 6000 rpm safely. These rotors are very very simple compared to an squirrel cage, should be pretty balanced out of factory. In that case it would be a better motor than industrial ACIM.

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peskanov
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ABB reluctante motor

Post by peskanov »

Richo,
agreed.
I specially like what those motors offer for light vehicles; ACIM is so innefficient in small frames.
Could be a good option for motorcycles, karts, quads, quadricycles etc...

BTW, a friend of mine is talking with ABB. The rep. showed him some laminations from the rotor, it seems these are pretty thin.
Maybe I will be able to play with one of those motors soon.

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peskanov
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ABB reluctante motor

Post by peskanov »

Oops, now I see I forgot to link the new ABB catalogue:

http://www05.abb.com/global/scot/scot20 ... s_RevD.pdf

Also, I found today a nice presentation about SRM. It's introductory, but contains lots of relevant info and pics about manufacturing. It's interesting to see that epoxy filling has been proposed and tested (to improve mechanical resistance to overtorque).
The presentation also explains why sensorless control is as efficicient as the sensored, closed loop one.

http://eam.tugraz.at/fileadmin/user_upl ... r-Graz.pdf
Last edited by peskanov on Thu, 01 May 2014, 00:14, edited 1 time in total.

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