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Discussion Starter · #1 · (Edited)
I am coming at this project from a slightly different starting point to many others. My skills are primarily in software and electronics. Consequently, I have started my project at the electrical end rather than the mechanical end.

I will follow the guide on how to write this post.

Your skill level with auto mechanics and fabrication

Essentially none (yet). I can replace parts if they attach with bolts, I can measure and drill holes accurately, I have some experience with CAD and 3D printing. I have no skills in welding. I understand a lot of learning is going to be required in this area and very much hope I can acquire these skills as I need them.

The range you are hoping to get what level of performance you are hoping to get

I am largely unconcerned with this. If I can get a range of a couple of miles for testing I will be happy. My goal right now is not necessarily a useful vehicle, but an exercise in learning the process and testing my electronics.

How much money you are willing to put into your project

An absolute minimum. As above, I have very low expectations for my initial build and consequently intend to spend very little. I intend to take my time and buy things as and when I need them.

What parts you've already considered, if any.

I have recently acquired a 30kW 3-phase 2-pole motor in a 160L aluminium frame. I hope to use this with my DIY inverter (already built) running at 288V. This will produce 15kW, but could potentially be upgraded to 30kW+ in the future by either rewinding or adding a voltage converter to my inverter.

What else?

I believe that I will likely use the existing flywheel, clutch and gearbox setup from the donor vehicle.

I am comfortable with the electrical requirements including my DIY inverter, fuses, circuit breakers, contactors, precharging, DC to DC 12v battery charging, and now just about got my head around high voltage battery charging and balancing.

First question

The biggest issue I have at this stage is that I have not chosen a vehicle. I need something with an engine bay large enough to accommodate the fairly large 160L motor frame, but still light enough to be viable as a low power electric vehicle. It seems that a vehicle with a reasonably large longitudinal engine and a rear wheel drive is going to be the answer, but many of these are large heavy cars. I'd appreciate any specific suggestions, or general advice on the types of vehicle to consider.

For quick reference, the motor is approx 13 inch diameter, and 18 inches long (excluding shafts, 4 inch front, 2 inch rear).

I am hoping for a little hand-holding with the mechanical aspects, particularly getting the motor mounted in the engine bay correctly, which is currently the biggest gap in my understanding of the process. This image of Johannes's engine bay roughly sums up what I'm aiming for. It can be seen that space is tight in terms of the size of the motor. http://johanneshuebner.com/quickcms/files/DSCF4013.jpg?t=1501541381435 so I don't want to get this wrong.

Thanks all for the excellent pointers from folks here so far!

Edit: sprocketman has kindly sent me a picture of a BMW 3-series bay which has plenty of place and a longitudinal mount, so this seems like the type of vehicle I may want to start looking at.
 

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The biggest issue I have at this stage is that I have not chosen a vehicle. I need something with an engine bay large enough to accommodate the fairly large 160L motor frame, but still light enough to be viable as a low power electric vehicle. It seems that a vehicle with a reasonably large longitudinal engine and a rear wheel drive is going to be the answer, but many of these are large heavy cars. I'd appreciate any specific suggestions, or general advice on the types of vehicle to consider.
...
Edit: sprocketman has kindly sent me a picture of a BMW 3-series bay which has plenty of place and a longitudinal mount, so this seems like the type of vehicle I may want to start looking at.
While a longitudinal front engine and rear wheel drive was once the normal configuration for most vehicles (to the point that is sometimes referred to as the "conventional" layout), it is now typically used only for
  • large cars
  • luxury vehicles
  • sports cars
  • high-powered cars
  • trucks and larger commercial vehicles
BMW is an interesting example because most models are designed to accommodate relatively long inline six-cylinder engines. Here, any BMW is expensive because it is some mix of large, luxury, and sports... and that's typical of the brands that tend to use this layout. While there are always people claiming to get a wonderfully good deal on a vehicle like this, I wouldn't count on it. I would also be concerned about the cost of parts, although that may not be an issue in the UK; here, it is assumed that anyone buying a BMW has money to burn. I know two guys who really liked their BMWs, but got rid of them when the final drive ("diff") started giving trouble... two issues there: good cars don't have diff problems, and that must be one expensive unit to trigger ditching the car. Personally, living here, I would not touch anything from BMW or Mercedes, but a BMW may make good sense in the UK.

Sports cars often have the desired layout, but are typically neither cheap nor easy to pile a bunch of battery into. Yes, a few people in this forum have jammed sufficient battery cells into a tiny Triumph Spitfire to make it work, but with some "interesting" battery packaging. There are some Mazda Miata/MX-5 conversions, too, and that's a very small volume of car. This type of vehicle may have very restricted engine space length; for instance, the current MX-5 and Mazda 3 compact car use the same engine and have the same length available to hold it - the longitudinal layout doesn't provide any benefit.

The easiest choice here in Canada would probably a compact pickup truck. There is engine space, the separate (from the body) frame is easy to work with for motor and battery mounting, and battery packs can be mounted under the cargo box. Although there are none sold here now (the smallest trucks are now much larger than they were), there are still examples of the Ford Ranger, older Chevrolet Colorado, and early Toyota Tacoma available. I don't know what sizes and ages of the equivalent Ford/Mazda, Toyota, and Nissan trucks are readily available in the UK. My guess is that they might be less common there than here.

This image of Johannes's engine bay roughly sums up what I'm aiming for. It can be seen that space is tight in terms of the size of the motor. http://johanneshuebner.com/quickcms/files/DSCF4013.jpg?t=1501541381435 so I don't want to get this wrong.
Although this car illustrates the challenge with engine size it also demonstrates that the problem is manageable: it is VW Polo Mk2... a car so small that VW never sold it in North America.

One issue with the longitudinal engine and rear drive layout is that the driveshaft breaks up potential battery locations; it's easier to wrap a fuel tank around a shaft than to package fixed-size cells around one. On the other hand, front wheel drive EVs tend to end up with a pile of battery in the back, and so are bizarrely rear-heavy for a front-drive vehicle.

I realize that none of that provides any answers, but I hope it provides some food for thought.
 

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Discussion Starter · #3 ·
Thanks for the pointers. Trucks are indeed not very popular here. Almost all vehicles (particularly low cost ones) are compact FF hatchbacks. Those that aren't are far too heavy to be suitable for a moderately low power conversion.

I measured up the engine bay of a VW Golf today and it looks like the motor *may* fit in this vehicle (it will be very very close taking into account the need for an adapter plate). In the interests of getting on, getting my hands dirty and learning something, I'm going to go ahead and get a cheap Golf, pull the engine out and see what happens.

I am thinking that if there is sufficient space between the gearbox and the end of the engine bay, great, I will go ahead and install the motor directly to the bell housing, utilizing the existing gearbox, flywheel and clutch.

If it does not fit, I see 2 options:

1) Buy a slightly smaller motor (160M 132L housing instead of 160L). Johannes's motor is a 132, but I can't find anything with a decent power output in this form factor.

2) Remove the gearbox and install something else, perhaps a chain driven diff, allowing more control over placement of the motor and switching to direct drive.

Neither of these options are ideal and I am mostly regretting my decision to buy a large motor without considering space, but I am learning :)
 

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Neither of these options are ideal and I am mostly regretting my decision to buy a large motor without considering space, but I am learning :)
Hey cat,

I wouldn't let a early part purchase ruin or encumber your whole project. Cut your losses so to speak. 2-pole motors are rarely used, if ever, for EVs. Look for a 4-po!e. Also try a 15kw model planing to run twice frequency and reconnect winding nodes for half voltage. You'll get same power and more torque for a lot smaller motor.

major
 

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Discussion Starter · #6 ·
Hey cat,

I wouldn't let a early part purchase ruin or encumber your whole project. Cut your losses so to speak. 2-pole motors are rarely used, if ever, for EVs. Look for a 4-po!e. Also try a 15kw model planing to run twice frequency and reconnect winding nodes for half voltage. You'll get same power and more torque for a lot smaller motor.

major
Thanks for the encouragement!

This is exactly what I am thinking now. 132L 4-pole 11kW should be easily available, and I hope to be able to rewire windings in parallel for half voltage (sill 200V bit better than 400).
 

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fwiw, for example the ac24ls was (still is) a 4kw motor (@1760 rpm), they rewound it for a lower voltage (so you can run it at higher than 60hz) and are listing a peak power of 47kw, and 20kw continuous.

http://www.mp3car.com/filedata/fetch?id=2276747&d=1261144928

not just any induction motor can do that though, if it is rated for inverter duty that might help as well as having a higher efficiency rating. but generally the rated power of a motor on the data-plate is very conservative. but they don't typically take a break either in an industrial setting.

edit, so rated it makes 15 foot pounds @ 1760 rpm, and can probably do that for years on end, but in the above link you can see they are getting 68 foot pounds all the way up to ~4600 rpm for brief periods, with plenty of power available after 4600 rpm.

 

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Discussion Starter · #8 ·
fwiw, for example the ac24ls was (still is) a 4kw motor (@1760 rpm), they rewound it for a lower voltage (so you can run it at higher than 60hz) and are listing a peak power of 47kw, and 20kw continuous.
That's impressive. I've definitely overspec'd with my motor then!

I've also since realised that despite being rated at 30kW, it's really only a 15kW continuous motor, rated 30kW at 60% duty cycle, so going down to 11kW is really not much of a loss. Perhaps I could consider going even smaller to begin with, particularly if I go with an even smaller vehicle, which was my original plan.

I think I came into this with no idea just how under-rated these industrial motors were.

Thanks again!
 

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Thanks for the encouragement!

This is exactly what I am thinking now. 132L 4-pole 11kW should be easily available, and I hope to be able to rewire windings in parallel for half voltage (sill 200V bit better than 400).
I was trying to make sense " rewire windings in parallel"
Basic rules for a three phase motor. Alternating Current
Each phase is in series 4 coil sets (4 pole motor)
Each phase needs to be labeled start-finish

1st phase:
Each coil set has to be next to each other (slot) (that is the pole N-S)

Each phase has an offset of 120 degrees (3 phases = 360 degrees)

When done you will have six leads 3-start leads and 3-finish leads

You got two choices on hooking up the leads Delta or Wye IMPORANT With a wye connection you LOOSE 20% of your torque

http://ivanbennett.com/forum/index.php?topic=26.msg63#msg63






There is a lot more reading on my forum.


-----------
 

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Discussion Starter · #10 ·
I was trying to make sense " rewire windings in parallel"
Each phase is in series 4 coil sets (4 pole motor)
I understand you're the expert on this! My hope is that I can take the 4 coil sets and wire then in 2S2P instead of 4S, thus halving the total voltage required, but keeping the current in each coil the same. I believe may people do this, avoiding the need for a full re-wind. Does this make sense?

Of course this requires that the motor is wound with 2 separate windings per phase instead of one continuous winding, but I understand many are. Again, you're the expert here :)

There's a long thread about this process here: http://forums.aeva.asn.au/viewtopic.php?t=1237 and several people have recommended this as the best way to run a 400V 4-pole motor.
 

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Discussion Starter · #11 ·
My car has arrived. http://imgur.com/a/S7zvv

The space in the engine bay measures 520mm. This is enough for a 132L, almost certainly not for the 160L. I will source a replacement motor and upgrade to 4-pole. I will try to find a 11kW 132L with 6 windings, otherwise will have to find someone to do me a low voltage rewind.
 

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Discussion Starter · #13 ·

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I am coming at this project from a slightly different starting point to many others. My skills are primarily in software and electronics. Consequently, I have started my project at the electrical end rather than the mechanical end.

I will follow the guide on how to write this post.

Your skill level with auto mechanics and fabrication

Essentially none (yet). I can replace parts if they attach with bolts, I can measure and drill holes accurately, I have some experience with CAD and 3D printing. I have no skills in welding. I understand a lot of learning is going to be required in this area and very much hope I can acquire these skills as I need them.

The range you are hoping to get what level of performance you are hoping to get

I am largely unconcerned with this. If I can get a range of a couple of miles for testing I will be happy. My goal right now is not necessarily a useful vehicle, but an exercise in learning the process and testing my electronics.

How much money you are willing to put into your project

An absolute minimum. As above, I have very low expectations for my initial build and consequently intend to spend very little. I intend to take my time and buy things as and when I need them.

What parts you've already considered, if any.

I have recently acquired a 30kW 3-phase 2-pole motor in a 160L aluminium frame. I hope to use this with my DIY inverter (already built) running at 288V. This will produce 15kW, but could potentially be upgraded to 30kW+ in the future by either rewinding or adding a voltage converter to my inverter.

What else?

I believe that I will likely use the existing flywheel, clutch and gearbox setup from the donor vehicle.

I am comfortable with the electrical requirements including my DIY inverter, fuses, circuit breakers, contactors, precharging, DC to DC 12v battery charging, and now just about got my head around high voltage battery charging and balancing.

First question

The biggest issue I have at this stage is that I have not chosen a vehicle. I need something with an engine bay large enough to accommodate the fairly large 160L motor frame, but still light enough to be viable as a low power electric vehicle. It seems that a vehicle with a reasonably large longitudinal engine and a rear wheel drive is going to be the answer, but many of these are large heavy cars. I'd appreciate any specific suggestions, or general advice on the types of vehicle to consider.

For quick reference, the motor is approx 13 inch diameter, and 18 inches long (excluding shafts, 4 inch front, 2 inch rear).

I am hoping for a little hand-holding with the mechanical aspects, particularly getting the motor mounted in the engine bay correctly, which is currently the biggest gap in my understanding of the process. This image of Johannes's engine bay roughly sums up what I'm aiming for. It can be seen that space is tight in terms of the size of the motor. http://johanneshuebner.com/quickcms/files/DSCF4013.jpg?t=1501541381435 so I don't want to get this wrong.

Thanks all for the excellent pointers from folks here so far!

Edit: sprocketman has kindly sent me a picture of a BMW 3-series bay which has plenty of place and a longitudinal mount, so this seems like the type of vehicle I may want to start looking at.
My project car is a e36 3 series BMW and its a very good choice for this type of conversion. I dont agree with that other guy who is anti BMW. I have had BMW's for years and you just need to do plenty of research with what are the things to watch for. With a European car sold world wide you get the benefit of a huge variety of parts suppliers and it really drives down the prices on things. E36 you dont have a can bus to give you extra stress. My project is currently paused due to serperating from my wife but I can give you a lot of advice if you choose this car.
 

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My project car is a e36 3 series BMW and its a very good choice for this type of conversion. I dont agree with that other guy who is anti BMW.
I said that rear-drive BMWs were suitable for conversion with a large motor like this (due to their use of inline six-cylinder engines), which hardly sounds anti-BMW. I also noted the fact that they are expensive here, which is true; this may not be a problem for catphish... and I noted that.

... I can give you a lot of advice if you choose this car.
mons2b, if you read past the reference to BMWs which apparently set you off, you might have noticed that in post #11 - three months ago - catphish reported the arrival of the car which he chose... which is a Golf. It's good to know that you'll be helpful if he changes his mind. :rolleyes:
 
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