Coming soon, the greatest Favorit project ever! (Probably)

[fabdavrav]

I'd say that's a bit of a saving.....for just a bit of elbow grease!!!!!!

Edited 18 May, 2011 by fabdavrav

[OctyNik]

My dad and I just re-read the whole thread and we're both really impressed with the work so far and the plans (especially on the dashboard, it's really nice and clean, and you can't tell it from OE) I really do think it's like a 'factory' special rather than a project!

Motor is looking nice and clean as well!

Would really like to see this and get some good photos of it! Where abouts are you based? Shame you can't make GTI International - having an EV on the stand would be brilliant!

[favguy]

Hi all,

Just realised post No. 66 was still showing my first (crappy!) effort for the battery cell monitor display, so I've re-written it with the new pics. of the re-worked effort, a vast improvement me thinks...

As for the motor, well, it gets finished tomorrow, so I'll have the during restoration and finished pics. up here within the next couple of days, you simply aren't going to believe the contrast with how it started out!

[fabdavrav]

Just realised post No. 66 was still showing my first (crappy!) effort for the battery cell monitor display, so I've re-written it with the new pics. of the re-worked effort, a vast improvement me thinks...

That looks sooooooo much better!!!! Bet the first thing people say when they see it (not switched on) is, "is that the satnav?" With all these hightech displays.....could you resist the urge to do a K.I.T.T. red chasing led strip and the wooo...woooo sound?????

Edited 24 May, 2011 by fabdavrav

[favguy]

Well... Although my motor isn't a Warfield, they do a motor that looks just like the finished version of mine (see more below!) and it's called the Warp9 lol!! Apparantly owners of these motors are often heard quoting Captain Pickard and shouting "Engage..Warp 9" as they set off...

Edited 25 May, 2011 by favguy

[favguy]

OK, So we'd got to having the motor taken apart, cleaned, old paint stripped and etch primed. So each section of the motor was now worked over as necessary, the main casing had the field coils removed and cleaned, then re-varnished using 1200v high temperature impact proof insulating varnish! The casing inside wall was then insulated with Nomex Polyester Laminate again rated at 1200v, high temperature to avoid any possibility of a ground short in the future.

Whilst the casing was stripped out, I also re-drilled and tapped it to allow the head assembly to be rotated 12 degrees anti-clockwise for brush advancement. This turned out to be fun, as 3 holes drilled out just fine then the 3mm pilot hole drill bit decided it would be fun to snap off in the 4th hole at 20mm depth 3mm below the surface of the hole!!

Anyway, 6 hours later.... after a combination of drilling down onto the top of the broken bit with a 5mm combination masonary/metal bit on hammer action! (usually useless but better than HSS bits for this task!)then disintegrating it with a narrow pin punch about 1mm at a time, then drilling down another 1mm, etc.., the ba***rd thing was finally out!

Unfortunately, after completing drilling the hole, it was now far too "slack" to tap succesfully, so it was drilled out oversize and tapped for a helicoil, with this fitted the job was done at last, the remaining 3 holes took all of about 20 minutes to tap out perfectly!

The pole shoes were re-painted and the casing re-assembled:

Following on from this, the end housings were top coated metallic silver along with the fan. The brush assembly was then washed with phosphoric acid to remove the build up of carbon and re-assembled to the head.

The fan was re-attached to the armature, after first blowing out about 30 years of compacted dust from the armature windings and inspecting it. Here we are so far:

Edited 25 May, 2011 by favguy

[favguy]

Whilst apart, the front end cap needed some work also. The lifting tag was removed as it will be of no use now that the motor is going to be face mounted to the transmission bell housing via an alloy plate. The face was then drilled and tapped for 4 x 3/8 UNC mounting bolts. (personally I prefer metric, but the rest of the motor is UNC, so it seemed bad practice to "mix and match" on the motor itself)

Then moved on to build up the brush assembly and bus bars in the head:

OK, next job was to press the new bearing into the front end cap:

[favguy]

OK, now the exiting bit starts, we get to build it all back up...

First the front end cap onto the armature:

You'll notice the top bearing has also been pressed onto the armature prior to the build up.

Then the main casing is lowered into place (having first been painted Skoda Sportline Red to match the car ):

Then the head assembly is carefully added to make the motor whole once more:

In the end I put the original brushes back in as having inspected them, they were in really good order, along with new brush tension springs, the end result is quite neat:

Edited 26 May, 2011 by favguy

[favguy]

So, exactly 2 weeks from picking the motor up in it's original sorry state, everything was double checked and it was powered up from a large 12 volt battery for testing and run for an hour to help re-seat the brushes and observe it for proper function. As it had no load and the brushes were advanced, even at 12v it purred up to around 1500rpm as smooth as silk

A few finished piccies:

And just to remind you of the contrast with how it started lol!! :

So there we have it, next job is to strip out the existing engine and transmission from the car and start working on the mounting plate to the transmission and the coupling.

Back soon...

Edited 26 May, 2011 by favguy

[fabdavrav]

I love it when you can take something that has not been looked after so to speak and clean it up and rebuild it so it looks sooooooo much better.....well OEM new out the box++++++ spec....... bloody brill!!!

Advancing the motor ??????? How does that work????? I thought that would have no effect on an electric motor???? :S

[favguy]

Advancing it...well, first you need to fully understand DC motor theory, and in particular, series wound DC motor theory, I won't pretend I do, I had a look at the formlae for it the other day and got a serious headache after 10 minutes! I just do what I'm told by a very well renowned and trusted DC motor Guru I know of in the US!

But here's the jist of it:

Advance for a motor is shifting the brushes towards the direction of rotation slightly. The best position for the brushes to contact the commutator is midway between the north and south poles, or neutral. However when the motor is under load, the magnetic field of the armature distorts the main field (from the stator) and shifts it so the "magnetic neutral" is no longer aligned with the mechanical neutral. This shift causes induced voltage in the armature coils as they exit the brush and cause arcing. This isn't a problem at forklift running voltages of 36/48v, but becomes much more of an issue as voltage increases to much higher levels.

One can compensate by shifting the mechanical position of the brushes to align with a "best guess" to where the magnetic neutral will be and reduce the amount of arcing under load. This arcing increases with voltage, current and speed, or any two, or any one of the three. That is why I say "best guess", because the EV traction motor is always changing voltage, speed and current as it accelerates. So, rules of thumb, and advice from experienced motor specialists are what most rely on.

If the arcing at the commutator gets too severe, you can end up with it "zorching" a ball of plasma running around it similar to what you get from an arc welder, needless to say, if this happens the motor becomes a very heavy doorstop

The rule of thumb for running at 144v is an advancement of between 10 & 12 degrees. So I've gone with 12 as I'd rather be safe than risk killing the motor!

Edited 30 May, 2011 by favguy

[fabdavrav]

OK my head now really hurts!!!!!! :S .....The most obvious way to look at it is you are changing the postion of the bushes in relation to the "shoes" which are fixed to the outer casing.....as these items inc the bushes allways remain fixed as they are all bolted to the casing! I suppose it's like trying to get a smooth overlap on crossover networks for speakers. :S

Edited 26 May, 2011 by fabdavrav

[favguy]

Yes,

That's exactly it, the physical work is to just rotate the brush assembly (in the head of the motor)in relation to the pole shoe position. In this case anticlockwise, as it runs clockwise looking from the head assembly.

As for the stuff you said about speakers :S I'll take your word for it lol!! I know less than nothing about ICE!

Regards, Paul

[fabdavrav]

ICE....hhhhmmmmmmm I have forgotten some of what I knew.......designed my own set of 2nd order two way cross overs with impedance and attenuation compensation!! And I hand wound my own air cored chokes!!! What fun!!! Also done car installs for friends....if I had time I would like to make my own amps....and bigger speakers!!!!

[pieman[vrs]]

Awsome thread favguy :yes:

All this DC motor theory reminds me of college days (am a sparks), wow 8 hrs a day of trigonometry. Am glad thats behind me!

Really great job ur doing here, am really enjoying reading it & cant wait to see more!

keep it up!

[st3f4n]

Great read, Some seriously amazing engineering skills, must be said. Your head must be massive to store all that info... Im also from Grimsby, Would be good to see it one day in the flesh

[favguy]

Hi st3f4n,

Would love to show you the car some time

Ok, making slow progress, got lots of materials on route at present, until they all turn up, I can't do a great deal.

I did pick up a spare transmission cheaply, this will allow me to prototype and build the adapter plate and coupling and mount and test the motor without risking damage to the cars original box, also means I can drill big holes in it to check alignment and run out at speed in the bell housing, wouldn't want to do that to the oringinal

I have a blog on an electric car site and one of the motor guys on there asked if I'd re-fitted the "wavy washer" on re-assembly of the motor! Turns out this was missing, presumably left out from prior maintenance, it pre-loads the bearings and takes up end float, so is quite important, it sits behind the bearing in the control end of the motor. So I whipped this off again and inserted the right washer, got to love the internet, I'd never even heard of these before, and 10 minutes later had sourced the right size and ordered one!, here it is:

Meet the new brushes, same as the old brushes I decided to order a new set of brushes after all, although the old ones were in good nick, as they did look a bit low with wear. Well, turns out the new ones were virtually the same length!!! doh!!! Apparantly they are meant to sit that low in the holder when new, anyway, I'll console myself with the suppliers comment that they are a new graphite compound that minimises commutator wear!

I did also give the motor a quick circumcision!! Compare with an earlier picture of the output shaft and you'll see what I mean This is in readyness for the coupling mounting, which will now be locked in place with a grubscrew, all will become clear soon..

And finally, although I didn't bother photographing it, I've changed the 8 bolts holding the end caps to the steel casing to high tensile grade 8 bolts and set them to a higher torque setting than before. I did this after noticing the originals had no head markings, meaning they were ordinary softer steel (probably grade 2). Makes sense I think as the motor is now going to be running at much higher voltage, current & speed than before.

OK, thats it for now, for what it's worth, back soon...

Paul

Edited 7 June, 2011 by favguy

[Phil-E]

Coming along great!

Like you say... where would we be without the internet and it's vast many users!

Phil

[Phil-E]

Also. Just been thinking. Have you worked out how much electricy this will require to charge from empty and therefore how much that will cost?

I noticed in a recent news article about electric vehicle charging points that, for example, a tesla roadster pulls up to 70A to charge itself!!! Obviously you have to have a proper special charging point installed for this. Not sure it would work through an extension lead from the garage! lol

Phil

[favguy]

Well if I use 160Ah cells (largest I will use, might go with 100Ah's yet) they will need about 170Ah's in allowing for losses, so assuming an 8 hour charge, charger output needs to be at 21.25A, with an output voltage at about 156v to charge the pack.

Voltage and current is inversely proportional, so with 230v in, charger will pull 14.41A, in reality at 90% efficiency, it will pull about 16A. Perfect for standard blue 16A socket and lead

As for cost this equates to 3.68Kw, so x 8 hours equals 29.44KwHrs @ 12.902p per unit (BGas Day), at standard tariff so, thats £3.79, although the night rate is only 4.497p and thats when most charging will be done, so that's only £1.32 for about 80 miles But then we need to add the cost of a battery cycle, assuming battery cost of £7,000 (that's why I might be using the 100Ah's @ £4,500) and cycle life of 2000, that's another £3.50, so total cost of £4.82.

For comparison, a diesel doing an average of 55mpg would cost you about £9.25 to do the same trip. this of course ignores wear & tear and servicing costs. (No exhausts, oil, filters etc. with the electric option)!

By the way, I haven't forgotten you all, done a lot behind the scenes, mounting plate is at the machine shop, the coupler was designed and tested, a big fail! So 2nd prototype has been designed and tested and is now great, needs to go into the machine shop for a finishing tweak in the lathe that can't happen until I get the new clutch plate, so I can strip out the torque damper

All will become clear soon...

Paul

Edited 17 June, 2011 by favguy

[Jonny5ive]

Epic project.

That is all.

[Phil-E]

Cool. Nice run through of the figures there.

Just looked back through the thread and can't see that you have said anywhere about how much power/torque that motor has. Apologies if you have.

Phil

[favguy]

Hi Phil,

Well as for performance figures... it's a bit of a lucky dip to be honest as the motor I'm using was never designed for it's new application and didn't come with any performance data, however... below is a performance graph for a Warfield Impulse9 motor, this is of very similar electrical construction, build and weight:

Bear in mind I'm running 144v and not 72v as per the graph. (I hope the graph means something to you, as I can't make head or tail of it !!)

Also, you can't directly compare HP for a petrol/diesel engine to an DC series wound electric motor, this is because you start with 2.5 times max. torque at zero rpm, and it drops away with increase in rpm's, then you change up and get the torque back, kind of exactly the opposite to an internal combustion engine!

Edited 19 June, 2011 by favguy

[Phil-E]

Think I can make some sense of the graph and yes I understand that it is completely different to a conbustion engine. Was just curious as to what the power is roughly equivelant to.

It should be a pretty nippy little car anyway. I doubt you will see the use of first gear much! Hehe.

[favguy]

Hi all, I'm back ...

Well I've been doing a little bit behind the scenes, but mainly waiting for parts to get machined and turn up etc. but now I've a bit of an update for you all.

The motor to gearbox coupler and mounting plate are finished, yeah!!, this is one of the most important parts of the project and has to be exactly right, and on that note I'll give you all a laugh by showing you my tragic first attempt at a coupler followed by the correct way to do it

Although I neglected to take a photo of it prior to cutting it up, my motor came with a useful female attachment (no giggedy's or other comments please! ) that had big lugs on it to attach it to the original drive shaft or whatever in its previous life, having cut these off leaving the hub, I now needed to end up with this on something that in turn would go onto the gearbox input shaft. Due to the very high starting torque from the motor, I also wanted some form of dampening to "cushion" the power transfer, the ideal thing being a torque damper from an original clutch disc. So after not really enough thought I concluded that using an existing damper back to front got me the right distance onto the gearbox input shaft and that I could weld directly onto this! So I went ahead and welded the hub to one of the damper plates:

(I can already hear those of you with engineering backgrounds tutting about why this is so bad!!)

I then realised that the springs in the damper come on one set at a time in a staged way, and only do this in one direction, so using it backwards meant they wouldn't work properly, so to continue polishing the turd I was now committed to, I altered the spring carrier to suit:

And here it is finished:

And the re-assembled finished job in all its glory:

I ran it up on the motor, got a cup of tea, stared at it for 5 minutes and thought about it, then promptly took it off, ground the hub off it and threw the remains in the scrap bin swearing about the amount of time I'd just wasted!! :wonder:

For the following reasons:

1, The heavy cast steel hub was welded directly to the 1.5mm thick damper plate, which is made of very, very, hard (and a bit brittle) alloy steel (it destroys HSS drill bits when you try to drill out the pressed holes!), I'm pretty sure it would crack in short order at the weld edge due to this.

2, The torque would be transferred from the centre out to the springs, the damper was designed to do exactly the opposite of this... asking for failure.

3, It was impossible to get the spring action progressive when running it backwards, after the welding mod, all the springs would work together, at least to a degree, defeating the point of having the damper in the first place!

4, As if that wasn't bad enough, it didn't run true anyway due to distortion caused by welding to the thinner steel.

5, And finally, you know when something just looks like a crappy design and you just know it's not going to work right.. well it smacked of that (even before i'd completed it to be honest!)

So there you have it, one great big crappy failure. So shall we start again?...

Edited 4 July, 2011 by favguy