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Luigi goes electric. Fiat 500 R + Agni 95-R

63K views 127 replies 16 participants last post by  tylerwatts 
#1 ·
Hi all,

Just wanted to share my latest project. I'm converting a 1973 fiat 500 R to electricity. I've created a blog that could help other do the same.

Please see luigi500.blogspot.com for more information.

Best regards

Rikard
 
#36 ·
Hi!

Yes I'm surprised myself! I'm going to do some more testing after the wheel alignment. A friend of mine has a small "race" computer that messures acceleration and so on

I'll post as soon as i get it done.

Best regards

Rikard
 
#38 ·
Thank you!

I noticed that the Agni gets hot when under load. The termistor used in the agni is not compatible with the kelly controller and i dont know if I can change it.

One thing that I might do is to modify the paktrakr. It has a temp reader in the remote. I'm going to se if I can remove that from the remote and extend it to the motor.

Whats the "max" running temp of an electric motor anyways?

Best regards

Rikard
 
#42 ·
Yes indeed, 90C is around the top temp you want to see on an Agni.

We have a little MCU overtemp device on the way to production that could be used to limit throttle or turn on a fan/pump at overheat - hopefully we'll have it up for sale in a month or two..

We've had great results with water spray cooling the Agni's - just inject a spray of water onto the outside circumference of the rotor through the vent holes on the endplate once temp reaches 80C or so, it evaporates off and sheds a lot of heat pretty quickly..

Well done on the car, very nice job - and perfect little getaround car!
 
#43 ·
Thank you Jozzer,

Do you have any pictures showing the spray mechanism? A pump, a nozzle, a water container, and a temp controlled relay that triggers the pump.

Found this on the web, it's actually from Cedric Lync himself:
http://ideas.egrandprix.com/viewtopic.php?p=85

"and you need about 40 millilitres per minute which you get from a 1mm jet fed by gravity with a 250mm head"

Not sure what it really means.
 
#45 ·
Thanks for the link to that question and answer thread Rikard. As usual Cedric's comments make a lot of good sense. His suggestion for water-cooling is very simple, as most of his solutions are. "Gravity feed" means he doesn't use a pump, just a container of water connected to a tube with a one-millimetre-diameter nozzle at the other end, to spray water on to the rotor.

The " 250mm head" is the height of the water in the tank above the nozzle (dvs vattenpelare).

The water container will naturally need a small hole in the lid.
 
#46 ·
Thank you for the explanation!
Would a small tank of water located 250mm above the nozzle give the same result?

Im thinking a small circuit that reads the agni thermistor value and triggers a solinoid when the preset temp is rearched. The solinoid opens the waterflow and when the temperature is back to "normal" the flow is stoped.

Best regards

Rikard
 
#48 ·
I'll try and post a pic of our pressurised system later in the week - all we have is currently installed on vehicles in hard to reach places!

Cedric has indeed experimented with a drip fed system sucessfully.
I prefer the pressurised system for a couple of reasons, firstly Cedric's method envolves drilling a hole near the bearing housing to let the water into the centre of the motor, and secondly the flow cannot be easily controlled (which is OK in a race setting where you are sure you will need the water, but not so good when you need it occassionally and don't want the water to be flinging out of a cold motor - as in this case).

I found when tuning the setup on the dyno that a high pressure atomised spray drops temps the fastest and with the least water being flung out, and was able to sustain over 20KW continuously with this method (even greater with the new 111RDR motors).
I use a 12v pump and nozzle setup from AquaMist in the UK (just down the road from me - specialising in watercooling race turbo assemblies).

Steve
 
#49 · (Edited)
For those interested, here is the temp and current graph of a 111 motor during a race with a water spray setup (pressurised) fitted.
You can see the motor heats up fairly rapidly (less than 5 mins from 50C to 100C), but as soon as the pump turns on at 90C the temps stabilise..

This data log was recorded with the same device I mentioned before that we use to control the pump.
 

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#53 ·
Hi Rikard,

It's better to have the nozzle aiming into the hole on the endplate (sidecase) towards the armature, the motor already draws air in through these holes and expells it around the circumference (stainless band).

The finer you can get the spray the more effective it will be - but that depends a lot on the pressure your pump can maintain. 1mm might be a good place to start..

Cheers,
Steve
 
#64 ·
Rikard,

Do you have any performance data? Things like weight, acceleration, top speed, range, whr/mile. It looks like it would be an ideal commuter vehicle.
Hi,

I haven't got exact figures yet but the top speed is about 110Km/h. Cruising speed about 90Kmh on highway.

I've borrowed a gtec from a friend so acceleration, 0-100kmh, and horsepower will be measured soon.
 
#66 ·
Thank you all,

I'm back from my vacation and I thought I would take the little race car for a drive. I ended up FRYING my brush holder and brushes pretty bad! A word of advice, if you are going 100Km/h+ and it smells like you grandmas old radio in your EV - find an exit :)


Does anyone know where to get a replacement holder and brushes? I heard about some aftermarket brush holders that would handle the heat better that the original.

Best regards

Rikard
 
#68 ·
Thank you all,

I'm back from my vacation and I thought I would take the little race car for a drive. I ended up FRYING my brush holder and brushes pretty bad! A word of advice, if you are going 100Km/h+ and it smells like you grandmas old radio in your EV - find an exit :)


Does anyone know where to get a replacement holder and brushes? I heard about some aftermarket brush holders that would handle the heat better that the original.

Best regards

Rikard
Hi riwe,

This looks pretty typical of the failures I have seen in the past. It is very likely, almost certain, that you have damaged the armature and I doubt it can be repaired. There is an outfit that sells hop-up parts for these Agnii including large heat sinks for the brush assembly. If I think of it, I'll post it. Jozzer would know.

I take a lot of crap because I recommend against these (and other brushed PM) motors. So I just kept quiet seeing you go down this path. I said to myself it is a small car and he will drive easy. Look what happened. Point is............you may be better off getting a proper wound field motor instead of repairing the Agni, especially if you're going to drive hard.

Sorry for your loss,

major
 
#67 · (Edited)
Oh dear - at least you'll know that smell in future!
We stock these parts - jozztek.com. Looks like 4 brushes may still be good, save those for future use (or buy only 4 brushes and a new holder and reuse these 4 - keeping them all on the same polarity so the resistances match).

Steve

PS, there are aftermarket holders avaialable for LMC motors that may fit, but the brushes are a different size (so you won't be able to reuse the 4 good ones), and I couldn't actually see much of an improvement when I tried one on the dyno. Ventilation around the motor is more important IMO..
 
#79 ·
Aye, that will clean up nicely - just clean it till the grooves are gone.
It's certainly not been burnt or overheated, though as Major points out some arcing did occur. The area near the centre/shaft doesn't make full contact with the brushes usually, in fact we usually remove a little meat from the inside edge of new brushes for racing. This area, where the copper sweeps in too the centre can effectivly contact before/after (depending on direction of rotation) the rest of the surface, causing some arcing. This can occur even without the brush damage that this motor has suffered.

Find a soft sanding stick the same size as the brushes, rotate the motor and push the stick against the copper until it runs clean and smooth.
To power the motor whilst you achieve this, either turn it with a drill/lathe, or modify your burnt brush holder to power only 2 brushes and allow space to insert the stick. To do this, try to cut the holder in half and refit only 2 opposite brushes, then connect to a power supply to spin the motor up (12v should do). If this isn't clear let me know and I'll post pics..

Unfortionatly, I don't have sanding sticks in stock and am having trouble locating a good source for them - Major, do you know of a company that might sell commutator sticks to order?
 
#86 ·
Unfortionatly, I don't have sanding sticks in stock and am having trouble locating a good source for them - Major, do you know of a company that might sell commutator sticks to order?
A google turned up these:

http://www.goodmart.com/products/pencil-type-resurfacers.htm

http://www.manvillemotor.com/cat/Commutator-Stones-C10912.aspx

But I thought there was an easy place. You have Grainger over on that side of the pond?

http://www.grainger.com/Grainger/ww...essing+stone&N=0&GlobalSearch=true&sst=subset
 
#80 ·
Hey!

Thanks guys!

Sanding sticks... My soon to be wife uses something like that for her nails but I'm guessing she won't let me use them in the garage :)
I'm thinking about my timing settings. Since the Agni is only working in one direction I altered the timing as described in the workshop manual. I thought that I would rev more than I do when on the high way. Typically I would like to do about 80Km/h when on the high way. The ratio in the gearbox gives me two choices, third gear and close to max rpm or forth gear and lower rpm. My guess is that in forth gear I would push more Amp's through the motor at a lower RPM and this would be bad for the "natural" cooling coming from the motor spinning. Would it be better for the Agni, from a heating perspective, to leave the timing at neutral position?


 
#81 ·
I'd go for about 1mm of advance, maybe a fraction more considering the vehicle weight and resulting current. Agni's need advance in response to more current rather than more speed..

Here's a pic of a cutaway holder and the sanding sticks we use. The square end of the stick is pushed against the armature - this ones getting a bit short, which puts fingers at risk!
 

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#83 · (Edited)
That sounds right - assuming the timing mark is actually at neutral:rolleyes:
With a new holder fitted you should verify this, the marks may no longer be correct..
To do this, connect to a low voltage power source, either one with a dial for "current" or in addition to a DC clamp meter. Spin the motor up and adjust the holder until the lowest possible current is being drawn. Mark this as neutral.
Then, turn the holder AGAINST/INTO the direction of rotation until the marks are 1mm apart. I usually allow 1mm of advance up to around 300A peak, up to 2mm if the motor is to be abused at 400A+ for short periods..

Steve
 
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