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harlequin2 03-21-2011 11:41 PM

Two Motors - are better than one!
 
5 Attachment(s)
I did mention that I used two motors in my car because I couldn't fit one big one in and someone suggested I start a new thread and put the details in, so I'll give it a go.
My original plan was to use a single, big motor such as a Warp9 or the equivalent from Advanced, but when I stripped the car down, I found I would have to mount it right up where the ic engine was and extend the drive shaft to reach, leaving a whole lot of waste space (where the transmission was) and putting the weight quite a long way forward. I had planned to put most of the batteries up where the radiator used to be and I thought the weight distribution would be front heavy that way.
I looked at the motor specs and decided that two Advanced L91s would give me more power and torque than an FB1 (9") and right up there with a Warp11. And for somewhat less money too. I thought also that perhaps one could have an "economy" mode with one motor and a "power" mode with two!
So I sat down and designed a frame to hold the two motors, longitudinally ie one behind the other, with suitable couplings.
That was the first problem, as a coupling that could connect the two motors together was difficult to find, very expensive and extremely bulky.
The BMW E30 uses a rubber "doughnut" to couple the gearbox output shaft to the first, short, drive shaft section and this can obviously handle the ic engine's power and torque, so I thought to adapt this to make a coupler for my two motors. A trip to the local wrecker provided two couplers from which I could modify the 3-legged "spiders" that hold it all together. A bit of lathe work and some welding produced the first picture, shown loosely assembled on a motor shaft mounted in my customwood frame. The next shot shows the thing mounted in the real Al frame and connecting the two motors together. Number 3 is the actual Al frame made out of 10mm Al plate bent, curved, cut and welded, then a couple of shots of the drive shaft coupling off the rear motor.
The frame is designed to mount on the original rubber engine and gearbox mounts in the BMW, so the whole thing is free of any vibration or harshness.
Anyway, that's the mechanics of it.

Ryland 03-22-2011 12:18 AM

This idea is not common but it has been done before with good results, Zap electric bicycle kits used two motors, solectra chevy S-10 pickup trucks used two motors side by side, another company that converted geo metro gliders I think used two motors end to end and the drag race car White Zombie used two motors that ended up being grafted together to share a single drive shaft after a bit of time passed.
I think using two motors is a great idea and there is more then one way to do it, it doesn't seem that common for the home conversion but it does open up alot of options and I look forward to learning more.

Ranger4Free 03-22-2011 04:09 AM

multiple motor madness
 
That looks good.decent welds and nice fabrication. thanks for starting this thread..maybe finally ill get some sensible advice and answers(still think u shoulda called it multiple motor madness...(-:..LOL.) Iv also heard about the white zombie car mod and man does that thing shift...on a quarter mile strip it was caning porches,ferraris and anything else that looked its way!!best of all it is electric.The owner originally had lead acid batts in there but has since forked out on new lithium ion packs so now its even lighter and as we all know less weight=more speed!but me thinks the design is geared towards the quart mile runs,not a balanced medium of torque and speed with a good mileage.However I'm looking forward to getting into this thread now,and will start putting down different designs for twinning up the 2 motors-im inclined towards having them side by side if I go for a single seat design,with the 2 motors behind the driver above the rear axle,and the gearbox UNDERNEATH!!!!!!!!using CV joints somewhere in there...do I sound loopy yet??this project of mine will get done.but seeing as its gone 8am here and your reading what an extremely tired man is writing I wouldn't worry!!haha!its tomorrow when I'm not sleep deprived and I still sound bonkers that you should worry......once again thankyou 4 starting this thread.I can and will start making some input when I return from ZZZZZZ land.

harlequin2 03-22-2011 04:22 PM

Sounds like some interesting ideas!
I did want a car without a gearbox or clutch, just direct drive and enough torque to go from 0 to whatever in a reasonable time - and that is what I have.
The longitudinal arrangement was dictated by the available space, but side by side would be good. I think "Killacycle", the drag bike, uses two L91 motors in a side by side configuration and it does the standing 1/4 in about 7 or 8 secs!
Initially, I had the motors in parallel with a LogiSystems 1000A controller, but that one went the way of all LogiSystems controllers and emitted clouds of magic smoke. While it was still running, I had good starting torque (it would actually break the wheels loose if you floored it!) and the car reached 130 kph. Since it blew up, I built the Cougar controller which has performed well, if a trifle docile, but to get adequate starting torque I rewired the motors n series and that dropped the top speed to 110 kph. I have repaired the LogiSystems lump, but I'm not using it because its initial take-off is too abrupt, no matter what you do. I am thinking of building another Cougar control board and driving the LS power stage with it to give 1000A capability again, but with smooth control - and proper current limiting! But I am also looking at Paul's new 1000A design and have put my name down for some boards when they are available, so I will make one of those too.
By the way, how do you embed photos in this? So far I can only add "thumbnails" at the end of the text!

Ranger4Free 03-22-2011 07:08 PM

multiple motor madness
 
Your pictures were fine!!they appeared as thumbnails but when i clicked on them they enlarged and i could zoom right in close...so whatever you done it worked!!Anyway,when i originally starting asking these questions about multiple motors it was three-fold motivated...one:-i wanted to run two 72 volt motors from milk floats(dont know if you have them in your neck of the woods-but here in the U.K. there is an abundance of them...used to deliver milk,hence MILK floats.LOL...therefore an abundance of good 72volt DC motors to be had/salvaged/repaired),and in fact some of the newer floats have 90 odd(not sure of the voltages)volt motors...all good there then!Second:-I wanted to run two 48volt motors and Thirdly:-I can get absolutely extremely stupid quantities of 24volt motors...however i need to find out what type they are...which i will be doing in the next hour,well at least i'll go get one and strip it 'naked'..(ooo...if only i could find an abundance of sun kissed nubile females to do the same with!!!!woops...stop it Warren!!)in the next hour...ill post some pics of it as im doing it.These motors were used to pump hydraulic liquid for lifting!!but from first look they appeared to be series wound.soon find out though won't we!i am also going to post some pics of two milk floats that were souped up for a race against each other...one had an arrangement where 2 smaller dc motors started the float off then a larger dc motor kicked in for more top end speed...so i assume that the 2 smaller motors were for torque-y acceleration and the larger motor as i say was for top end speed!The other float(which won)didn't let anyone take pics of what they had under 'the bonnet'??!!maybe they had a very very quiet ICE in there....THE CHEATS..lol!!But you mentioned the killacycle...well,ive got some ideas about something similar...!actually...DING...just had an idea!i was thinking of using a Yamaha 535 virago drive shaft(they have a prop shaft that goes from the engine/gearbox that drives the rear wheel)so what if i used two of those,tinkered with the rear wheel to make it more car like(basically for looks cos it looks like a bike wheel and is too big)then i have a rear drive system that could be fed from 2...hmmm..maybe 4...hmm..maybe 6 of the 24 volt motors(if they cut the mustard)linked together by sprockets and chains...not just normal motorbike chains but heavy duty chains that come of the same junk that the motors are from...loads of torque might snap them if there not strong enough...they could drive the prop shafts!!!arrrghh...need coffee,pencil and paper!!my head is full of ideas for this!!i am also going to post pics of some sketchy designs of the EV's im gonna build...ie:-the chassis frame(s) and also pics of the shape etc...im going to use fibreglass for the bodywork.Im excited about getting these going....!!also,what do you reckon on using a 750cc BMW(also prop shaft driven drive)for its gearbox,marrying the motors to the gearing system????all these thoughts and ideas....!im going for those 24v motors soon and then im gonna strip it down and post some pics of it(them) ok.

MPaulHolmes 03-22-2011 08:11 PM

Quote:

Originally Posted by Ranger4Free (Post 227092)
(ooo...if only i could find an abundance of sun kissed nubile females to do the same with!!!!woops...stop it Warren!!)

hahahaha. That was hilarious. I'm at school, and the class is taking a final, and you just caused me to be very disruptive during their test (busted out laughing)! No more reading Warren's stuff at school.

Hey, harlequin2, is it the australian version of the power board and control board or the other one? I should know this. haha.

harlequin2 03-22-2011 09:32 PM

Quote:

Originally Posted by MPaulHolmes (Post 227103)
hahahaha. That was hilarious. I'm at school, and the class is taking a final, and you just caused me to be very disruptive during their test (busted out laughing)! No more reading Warren's stuff at school.

Hey, harlequin2, is it the australian version of the power board and control board or the other one? I should know this. haha.

Yeah, I had a bit of a chuckle too especially about MILK floats, I always thought it sank!

I bought the power board from you and the control board from Ian Bartie, the Australian one. I think you didn't have any at the time.

Also Warren, take no notice of the voltage rating of the motors. Just keep winding the amps and the volts up until your motor melts, then back it off a bit.

Ranger4Free 03-23-2011 12:28 AM

strip that motor down to its underwear....!!
 
Well,took me a little longer than i thought....!Ive posted the pictures on here...as you can see it was being used as a hydraulic pump,and getting all that off was a real pain...the bottom housing was full of old hydraulic fluid.There not bad little motors actually...really clean on the inside,but saying that this was one of the better ones that,unlike some of them,had been partially protected from the elements by corrugated sheeting!!and when i say there are a few of them i mean a good few...possibly 16-17 good ones in good condition,maybe about another 21 that are just completely rusted away,literally crumbles away as you goto pick them up...!i may post a pic on here of where they are(just one of my regular salvage sites).These people are crazy to be chucking these...and don't worry...they definitely have been chucked as i know someone who works where they come from!im not going into it on here but the word insurance has relevance!!Aaaanyway...back to the matter at hand!im thinking of maybe connecting these longitudinally in two rows-6 in each row!!!!!told you to worry when im not sleep deprived but still sound loony!!!maybe it can't be done...maybe it can!but before i start thinking about machining,hmmm,what would it be...5 connections for each row.Im thinking of then running the 'turning bit'(sheesh...im useless aint i?)straight onto and into the bottom end of the 750bmw motorbike engine...that is to say attaching /connecting it to the crank shaft...obviously there'll be no cylinder head to the engine as what do i need with the pistons!nada!or i may just run it straight into the gearbox...i really dont know yet.ill have to have a look at the Bimmer engine,which is in bits anyway.My dad had split that engine. Unfortunately my dad passed away last June...boy,i could sure use his help now.He was good with electronics as well!o well,ill figure it out.My dad originally wanted to use the bmw engine for a trike.Hmmmm...maybe thats still on but without fossil fuels.
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Harlequin....how have you got your motors running....straight to the diff???You say you have no clutch or gearbox.See,i always thought that would cause problems....!!For me i have 3 embryonic projects.Think i explained in another post what they were....but im just wondering what can be done with these particular motors...it would be a shame to waste them!THEY MUST BE USED...*warren hears a brass band fanfare playing as he types that*....
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i'm sure the bimmer 750 gearbox would handle this...i mean motorbikes are (all) torque (and no trousers) handlers anyway arent they....!even if i put just 6 motors longitudinally(how you harlequin put your 2 together)thats 144volts...ahhh...now heres a question...and please everyone just bear with me cos this is all a learning curve for me(sometimes it scares me and i hug my welder for comfort)...is it important how many watts each motor is??and also the part that has the 24v-80a label on looks to me very similar to a starter motor(solenoid)????...what is it anyone???you get 2 stars if you get it right and a thumbs up!!also there are 200amp fuses with all this lot(Paul...any good for you??)....but my favourite bit on all this is the little red L.E.D...simple things please simple minds!!lol!
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if my pics arent here then someone needs to help me learn how to....ta!

harlequin2 03-23-2011 12:53 AM

Oh dear, what a long rambling post, just like the ones I do when I've had a glass (or two) of red wine.
Firstly, your pictures didn't appear. Don't ask me, I can barely get mine up there, let alone put them where I want.
Second/Third?fourth - whatever, if your motors are rated at 24 V and 80A, that's only just under 2 kw which is pretty useless. Now, that will be a continuous rating (I'm sure) and you can overdrive them by heaps as long as it isn't for too long. For example, my L91 motors have a continuous rating of about 14 kw each (x2 for 28 kw) but they can do a peak of about 47 kw (94 kw for 2). gliding along the road at about 55 kph takes about 16 kw or so - maybe a bit more - and that's only 8 kw per motor, so they only get a bit warm Acceleration is where the big power demand is, but that's only for a short time, so no prob. Seems like 110 kph needs about 26 kw or 13 kw per motor and that's getting close to their max rating, so driving for an hour at that speed will warm them up and it does, they get up to about 75 deg C.
Now, you have your pissy little 24V motors that can do 2 kw continuous, you can probably overdrive them by a factor of 5 in the short term, for acceleration say, so you can get 10 kw. But you need a continuous power capability of ??? depends on the size, weight, aero drag and such. A motor cycle will need about 6 kw continuous to go 100 kph (Jeez, that's a rough guess!) and a car about 25 to 30 kw, so your bike will need 3 motors and a car will need 15!
These figures all just ball-park estimates, but based on my experience with both bikes and a car.
The mechanical coupling of all those motors will be the biggest nightmare. Two motors in parallel, easy, just a couple of sprockets and a chain - how do you take the drive off? In series , also easy as long as they are double ended motors.
You go figure out the mechanics and the electronics is a piece of cake!

Ranger4Free 03-23-2011 01:00 AM

i know i do ramble and going to make a point of NOT doing it...!The motors are not rated at 24 volts 80 amps...no no!that is the little starter motor solenoid thing...sure thats what it is!!i cant get the pics up cos of there size so im going to retake and post again or fiddle with a picture editor.Hold tight and youll see what i mean about the motor!!the main motor is not a tiny affair...they would work well.let me post the pix....
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The motors are double ended so the coupling of them i cant see being a problem for me...i am pretty good mechanically.I'll lathe coupling blocks...the ends are splined as well...thats no probs at all!the motors arent pissy either...(how dare you call them names...LOL)


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