My Random Eco(no)-Related Things Thread

[Stubby79]

I'd love one of those axle/motors. 400v isn't going to be necessary...unless you want to hit whatever the Lexus' max speed was.

See? Battery pack was "only" rated for 288v. 400v is the system voltage. Toyota uses a voltage multiplier, something else I would love to get my hands on, that presumably is used to boost battery voltage (perhaps only when necessary) to get more RPMs out of the motor. And maybe increase efficiency? Dunno, since there would be losses from boosting the voltage.

The Insight uses a 600v, 250a IGBT brick. The Civic hybrid has a 300a one. If you had a 288v battery, at 300a, you'd be able to put out 86kw at top speed. Lets say it maxes out at 1000 rpm at the wheels...that would put you in the neighborhood of 600 ft-lbs at 300 amps, at the wheels, after gearing. Bit weak, compared to a first-gear take-off, but after that, you'd be laughing. (if I didn't mess up my math)

Of course, we need to figure out how to control the IGBT first. and then you need a lot of batteries.

[freebeard]

I'm wondering what to do with one. I'm not saying we should smuggle it across the border, but maybe we could talk about smuggling it across the border.

My plan B is to query some local electric vehicle association to see if anyone wants to test it. The original thread was all about 'overclocking' one. There was a Korean market/trailer towing option for external cooling but the pump was as $$$ as the drive unit.

"Buck converter' is the term of art I've seen.

[Stubby79]

Just read(skimmed, looking for pertinent information) through the MGR hotrod thread at last. Started off well, then like 8 pages of no (motor) progress before picking up out of the blue...then it totally died off.

Kinda hard to believe they got the motors running and then completely lost interest?

I'm no whiz (at electrical engineering) at this like Paul...just good at problem solving. I'll leave the real brainwork required to operate a complex motor properly, from scratch, to someone like him. I could replicate his work with a proper schematic, use his code, but not come up with it myself.

The basic concept of turning on each phase, in order, and of other basics, like monitoring current, I can wrap my brain around. And cheat by using off-the-shelf parts and modifying them to suit my needs. But who knows what weird things start happening when you're running high currents and high voltage. I'd have to wrap my head around the math that Paul uses, for starters. Don't think I have that kind of dedication.

Was good to see they figured out the resolver, got the motor running. Would be nice if they continued it, or else "published" their work up to this point(maybe they did?). I thought that was going to be the major draw-back. My problem-solving side was thinking to replace it with something simpler that would work...hall sensors. Which is what I'm thinking for the one on this little motor/generator. a 3d printer would come in handy for making perfect, replicatable(is that a word?) parts. I really should look in to building one...uhg, a project just to make parts for other projects?

I've now got plenty of motors to work out how to drive them successfully...if I ever get them running properly, I'll consider smuggling one of those MGR units.

Not to try and write off your efforts so far, but if ya really want an electric bug, a brushed DC motor with the original gear box would be infinitely easier to put together and get you rolling, at least. (You could go for a big brushless or AC motor instead, but you'd be paying through the nose for off the shelf components).

I'll admit the MGR unit is much more attractive...no gearbox! I would stuff one in the back of my Insight...or maybe even in the front. Just gotta get those guys to continue their work or tell us hoe to replicate what they've done so far...

[Stubby79]

Prioritizing...a necessity. Let's go over my priorities: (I suggest anyone else taking on any kind of project do the same)

Economy is what it all boils down to, for me. Doing as much with as little drain on my resources as possible.

Anything that's "consumable", is, in the long run, is simply bleeding resources (money). So I have a strong attraction to minimizing the cost of these consumables, either by reducing the use there of, or else finding an alternate consumable that is notably cheaper. The reduced impact on the environment is a happy consequence, one that I'm glad for, but not my driving motivation.

Resources includes time and effort. I have limited spare time, and even less energy/enthusiasm to spare. Look up spoon theory for understanding of the latter; my excuse might not constitute as strong enough to warrant it, but it gives you an idea of how I look at and approach things. My projects and whatnot have to be worth the effort (or lack there of) that I put in. Most of what I get in return is the satisfaction of overcoming a hurtle and the resulting enthusiasm to try and continue. When I get on a roll, I can be super productive for weeks. Eventually I over-do it, or fail hard enough that, either way, I have to recover before continuing, and usually on something else entirely, to get the ball rolling again. My EV project died of neglect - and a stupid oversight - after being too disappointing for me to get back to. I enjoyed the process, though, just wish I hadn't made that simple oversight that killed half of my batteries. Not worth the cost to replace them on something that was a dissapointment...throwing good money after bad and all that. Same with the effort that would have to be put in. Would be much smarter to buy a used Leaf, and not cost much more either.

I'm obsessed with getting what I want/need for projects for as little $$ as possible, like this new motor. Always thrilled when I find such a deal. I could pick up a little 2 or 3kw brushless motor off Aliexpress for about the same price as this one. Much higher RPM, much less durable, much less potential power output. More stout motors on there would cost from $300; one of this power potential, more like $1000. So, yes, I am thrilled to have found these.

Efficiency is another key priority. To me, this reflects in having as light, as small, and as aerodynamic of a vehicle as possible...while still managing to be convenient. There's no point in me spending an hour riding a bike to work every day, unless it's all I could afford to do. (I rode my Honda Cub to work for a couple of years, as it was the most affordable-to-convenient way to get there). It should be enclosed - for weather and aerodynamics - electric, for fuel costs, three wheeled - so I don't have to put my feet down, somehow, while in an enclosed vehicle - and cost as little to insure as possible. That's what I'd like, ultimately. It's a pretty tall order, mainly because of all the ridiculous road and insurance laws around here, but it's still something I keep puzzling out in the background.

So, also regarding efficiency, I look at motor/controller efficiency, battery efficiency, minimizing other electrical draws (waste). Batteries are prohibitively expensive and add weight, so I look to minimize where I can. We end up with things like brushless motors and LEDs as a result...

Back up a bit to effort & convenience...gasoline, diesel and electricity take little to no effort to obtain, so I lean towards them. I love the idea of propane - it's half the price of gasoline around here, burns clean, doesn't spoil, and never spills...it's as close to using a battery as you can get without actually using a battery - but it's not convenient to fill up with. Oh, maybe, with a properly converted propane vehicle...but that's prohibitively both costly difficult to implement. So gasoline, diesel and electricity are my poisons of choice. Diesel's efficiency is enough to offset it's additional drawbacks. Electricity is the best, all around...only drawback is the cost of batteries.

Insurance costs are high on the list of wasteful expenditures. I have to pay as much for each additional vehicle on the road as I do for the first. I spend more on insurance than on gas every month. Not legal to drive without it. A 50cc/1500w "limited speed motorcycle" is the cheapest, besides a trailer, to have on the road...$20-30 a month, vs over $100 for a car; can only have two-wheels, though. Electric bikes don't require insurance, and can have three wheels...though to be legal, they have to have limited power and top speed. You can get away with quite a bit more with one, though, compared to something "street-legal".

Hmm...I think that covers my priorities. Why bother spelling it all out? Perspective. Who cares about some silly, little, dirt-cheap brushless motor that I can only get a few KW out of? Within the perspective I just gave...ME! Guess I never grew out of my obsession with doing as much with as little as I got use to when I was poor in my 20s. Just because I can afford more, now, doesn't make something "better".

My eventual goal? To build that three-wheeled, sit-down, enclosed vehicle...and that took a big step forwards a week ago when I brought home a dirt-cheap, "for-parts" Piaggio MP3. That was a bit of an adventure...some day, I'll build it. Unfortuntely, it's likely to take me years at the pace I get things done...in the meantime, I've got the Insight, which, short of an EV, is the next best thing.

[Stubby79]

Not impressed:

[Stubby79]

Tried taking it apart, no dice. Had to buy a 27mm socket to get the nut off the pulley. Odd size.

22mm keyed front shaft:



14/12mm tail shaft:





Thought I'd lost the key...spent 10 minutes looking for it on the floor, only to find it hiding on my bench under the motor.



No photo, but good to note...the 4 big bolts clamping the two halfs of the unit together are in a lovely square, making it 6" square in the middle...nice and tidy for use as mounting points.

And on a side note, I had a regular alternator pulley on my bench, and it just happened to be the same 17mm that both my treadmill motors use. Nice fit:



Can probably turn it around and make it closer to the body of the motor.

[Stubby79]

Another one arrived.

First thing I noticed was the tag saying it was from a 2015 model, and the larger plug on it. It reminded me that I read, somewhere along the way, that in 2013, they upped the power output. I eventually tracked down a snippit that said they were 8.5kw to begin with, but changed in 2013 (presumably for '14 model year?) to 10.5kw. Interesting.

For comparison:


Thicker wires too:


Nothing looks different inside:


Thought they just changed the connector, but they had to widen the casting a bit to make it fit:


Otherwise, they seem identical. Same thickness of windings and number of strands, voltage output spinning at the same speed is identical, pulley and coolant tubes are the same size and they weigh exactly the same(at least on a scale that only does 1/10 of a pound increments).

Hmm. Interesting. Guess they decided the internals were a bit higher rated than the externals? Or just decided it would be cheaper to push it to it's limit rather than redesign the whole thing.

The short bus-bars(the solid metal the wires are bolted to) on the "8.5kw" are a nice shiny silvery color:

(They're reflecting what's around them - the gold of the bolts to the right, the black of the insulator to the left.)

Whereas the "10.5kw" one, the bus-bars have that lovely dark rainbow effect caused by heat:


Maybe they changed their generation strategy for fuel efficiency, opting for more amps at less volts? Lower engine speed = more efficient for low power output, right? right. Your guess is as good as mine.

Part number changed, though it's close:




The junk yards seem to think they're the same. Maybe they send the plugs with them for a reason(though it's probably just because it's quicker to cut them out). With the plug, you could hook a later one up to an earlier model with no bother.

Digging around, trying to find anything solid on the kW rating, I found a snippet that explained the hybrid starter-generator (HSG) as being a "IPMSM" - an "Interior" Permanent Magnet Synchronous Motor...well, that explains a lot(or at least gives rise to theories that make sense) . Like...the low level of cogging...why the brushless control found it easy to pick up the back EMF to determine timing...and presumably why there was such a large difference between the input voltage on the controller and the rectified voltage output. (Square wave vs sine wave)

As it's a PMSM, it can supposedly reach 95% efficiency. I suppose I could look at so-called sine-wave controllers...there's a 3kw, 72v one for under a hundred bucks on Ali...but if I ever want to see full potential out of these things, I need to look at Paul's 3-phase, vector controller...

That sounds like too much work.

[Stubby79]

Originally Posted by Stubby79

I didn't know what a reluctance motor was until about a week ago. In my typical fashion, I didn't pay any attention to a technology that was out of my price range...none what so ever. Took one look at Paul's AC controller thread and assumed it was for induction...I mean, that's what Tesla runs as did a few others; assumed the rest were running a form of brushless DC. Oops. Very close, very similar, but not quite...

FWIW, the netgain, like most of the others these days, is not a simple reluctance motor...they call it a "Synchronous Reluctance Internal Permanent Magnet (SRIPM)" motor. The permanent magnets are equally important as the reluctance side of things.

And to make matters worse, there are other names for the same thing!

I can thank google for sniffing my searches and recommending a couple of youtube posts, including Tesla's "new" motor tech...which appears to have taken them a few years longer than everyone else to adopt, unless that was just on the model X which the video was about.

Anyway, just looked at the Netgain motors. The $4k US is prohibitive to me, at least for a just-for-the-fun-of-it project, but...nice efficiency map. You'd basically be running in the >85% area of the map most of the time, compared to a BLDC which would max out there. That's impressive. And all by hiding magnets inside of laminations...I wonder why it took so long to figure that out and bring it to the market. Ok, I know switching speeds/losses had something to do with it, but still...oh, and that Netgain controller only weighing 9lbs is also impressive, for the power output.

I gotta go, I'm drooling and this is making my head hurt to think about!

These "HSG" "IPMSM" are the same thing...Tesla's IMPSynRM is the same thing...everyone does their rotor design a bit differently, all in the name of efficiency (or power-to weight or whatever their specific design is meant to do, but efficiency/range is where the money is, imo)...but they're all just the same thing in different flavors.

Vector control = field-oriented control = field weakening in a reluctance motor. Since these motors are a PM/Reluctance hybrid, it works on them, raising the rpm...while retaining the low-end grunt(torque) of a PM motor.

Super neat-o! (So much for sep-ex field weakening).

When I read "Interior Permanent Magnet" I was like..."Why???". Seemed at first thought it would make for weaker magnetism than having the magnets right on the outside of the rotor, second thought was simply to be able to contain the magnets safely at stupid high RPM.

I wasn't considering the iron - wasn't even considering what it was made out of, to be honest - and how it becomes magnetized when in a magnetic field. Duh! Didn't realize it was reluctance. I knew what reluctance was, electrically, didn't put it in context with magnetism and iron in a motor. Yeesh. Only because of youtube that I do now:

https://www.youtube.com/watch?v=esUb7Zy5Oio

(gets really interesting at 9:38)

Wasn't sure the HSG was the same. Makes sense that it would be, cuz this thing has to be able to hit 16000rpm...and if there was no field weakening, then you'd end up with a stupid high back EMF voltage, which you could compensate for, I suppose, and you'd not be able to feed any power in to it once it got above battery (or voltage multiplier) voltage, yet everyone (auto makers) claims their hybrid setups make power at higher RPM. Assumed induction...should have clued in then.

Anyway, back on topic...wasn't sure, half the reason I wanted to pull one of these HSG apart, but they don't come apart easily...but you can just barely see down inside through the back:





First shot you can't really see the laminations -- dang it, another word to add to Firefox's "dictionary"; stop correcting me when I'm not wrong! -- but look at how tiny those stator (another word!) coils are! The whole rotating field makes more sense when you have a lot more coils...as does the smoothness of the motor.

Second shot, you can just make them out. The gnarled-look to the metal on the rotor right beneath the coils. Dang hard to take a picture of even that much, but you can see it with the naked eye. Laminations, between - presumably two - mirror-bright (you can see the reflection of the coils on it) end plates, which are presumably there to compress the laminations tight. So, yes, we have laminations, so we have reluctance and everything that goes with it.

The thickness (thinness?) of the copper windings makes sense as well, seeing how small said coils are. Why others cram bars through there instead of wire also makes sense, as small as they are.

The whole BLDC bit has tainted my assumptions of what it would be like inside quite a bit. Considerably fewer - therefore larger - coils, and equally large magnets. Not a lot of difference between the one in my insight and the ones on my ebikes. While similar, this is definitely different. A lot more switching going on to get higher speeds with more coils...then again, R/C motors spin at stupid high speeds, so not much reason for these not to translate that in to less speed and more torque.

Speaking of BLDC motors...which are fed via square-wave (or at least trapezoidal) rather than sine-wave...I would have thought that a magnet going past a coil would naturally result in a a sine-wave, but supposedly not...why not? is it trying to be a sine-wave, only saturation is cutting the rounded top off of it? That's what comes to mind...trapezoid = cut-off sine wave. Just a thought...

Yes, I use this thread as a sounding board. Helps me put my thoughts together, trying to explain them...often find details I've missed or assumed inside my head along the way.



Almost forgot...the whole synchronous bit about how the rotor follows the rotating field and stays in sync with it...and how using one of these as a generator creates a nice 3-phase sine wave output...well...that means you could use one to drive another one -- right up until it you hit breakdown torque (where the motor slips out of sync with the input) at least.

You couldn't start the motor with any load that way, but once it got going, if you didn't put so much load on it that it would fall out of sync, you'd be ok. It would be quite a mess if it did, mind you...anyway, it seemed like a potential way to transmit power electrically, rather than mechanically, if you had reason to. You could use a brushless controller to get it(both actually) started with a load on it, even, then switch over to driving one of them mechanically to drive the other one electrically.

I tested it, using my cordless drill again. It started the driven motor after an initial twitch as it synchronized, so no-load starting is fine. Hold the driven motor from spinning and it just twitches in your hand.

With the drill on low speed, I could stop it spinning by hand, despite having more torque on the driver motor. With the drill on high speed, it was the drill that gave out instead (the BMS on the battery cut out from over-current). That was rather as expected. No starting torque, but the faster it went, the more torque it could provide. I assume this is due to the peak voltage output being higher, therefore able to make a stronger push/pull on the coils.

I'm really left wondering what the breakdown torque would be at high speeds. I would hazard a guess that if it was being fed the full 270v, it would be dang hard to stop it...as in you might see that 10kw without much bother. Or it might fall flat on it's face. Going to have to experiment, get it up to a decent speed with plenty of power behind it and see if I can stop it turning. That treadmill motor with an alternator pulley is looking like a good place to start to spin the driver motor...

Could have it's uses, if it works...serial hybrid on something like a motorcycle...battery/controller for in-town speeds, engine driving a motor as a generator for higher speeds.

Nah, it will probably fall flat on it's face and blow up first.

Another thought...so, the motor synchronizes with the speed of the input wave form. So if I feed it off of 60hz 3-phase "mains", it should work...but...but...but...it's not going to turn very fast. If it doesn't turn very fast, the back EMF is not going to equal anything near the input...but it can't go faster than the 60hz will let it...is it just going to create an awful lot of heat? You'd be dissipating whatever the voltage difference between the two is, through the coils...so yeah, I think it would just get very angry and overheat. HMM...

I'm OK with that. "For science!" BOOM!

[freebeard]

I didn't watch the whole video, but I notice they eventually admit Toyota did it first.

Back when I was trying to understand this, I found the Texas Instruments Youtube videos were the most helpful, but I don't remember which one specifically. If you watch these;

https://www.youtube.com/results?sear...iented+control

...and one uses an analogy of watching a target while being on or off a merry-go-round, then that's the one.

The first one is good.

[Piotrsko]

Might be wrong but 60 cycle is 3600 rpm so the thing will spin pretty fast with gobs of power unloaded.