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Tony Coiro
21 September 2010, 1438
So, I have been in the design stages for awhile now for the next bike and today I found something that might be the next bike. It's a 1997 Suzuki Katana 600, blown motor, bad tires, bad brakes, which coincidentally, is exactly what I am looking for for the next conversion. ($300) I'm not going to let all the cats out of the bag just yet for what I am planning to do but, I can assure you, one of the things I'll be doing has never been done before and is very, very not traditional. :D More details as the project advances, which might be slow.....freakin' college.

electriKAT
21 September 2010, 1447
Nice Tony. The '89-'97 Katanas are basically all the same. I've got a '91. I'm not sure why you're *looking for* bad tires and brakes, but hey, whatever. So how soon can you throw us a (ahem) kat or two? I'm curious since we've got the same bike. BTW, Nuts&Volts has one also.

ZoomSmith
21 September 2010, 1456
You guys are gonna need your own sub-forum if this keeps up.

EVcycle
21 September 2010, 1548
"never been done before and is very, very not traditional"

Um. yes this is both the same but true and the same thing...... TED!!!!!

Sounds like a cool project! ..... what ever it is. :):)

teddillard
21 September 2010, 1600
TED!!!!!

wut d'i do?

(ducks, covers)

EVcycle
21 September 2010, 1617
LOL!!!!

Nuffin, it just looks like something you would type! :):)

teddillard
21 September 2010, 1633
oh wait'll you see the book, makes no sense whatsoever :D

EVcycle
21 September 2010, 1659
I hope it has pictures...or at least crayon drawings!!! :)

teddillard
21 September 2010, 1702
oh crap, you've been peeking.
http://evmc2.files.wordpress.com/2009/11/1.png?w=640&h=625

EVcycle
21 September 2010, 1713
Very Nice!!!!! and everything is spelt correctly.

:)

GUFF
21 September 2010, 1832
Ted, nice picture.

Is that 10W or 10V listed under the precharge resistor? At 72VDC you would have just over 5 watts of power (briefly) so I am assuming its 10 watts and not 10V.

Tony Coiro
21 September 2010, 1942
I'm not sure why you're *looking for* bad tires and brakes, but hey, whatever.


Haha, you'll see but seriously, I was looking for bad tires and bad brakes. It will make more sense later. :D Also, what are the chances of 40 60Ah Sky Energy fitting in a Katana 600?

BaldBruce
21 September 2010, 2017
Haha, you'll see but seriously, I was looking for bad tires and bad brakes. It will make more sense later. :D Also, what are the chances of 40 60Ah Sky Energy fitting in a Katana 600?

Anything is possible. Well almost anything:). You will need a shoe horn, but I fit 24 100 ah into a 900 size sport bike. More casing material than mine but same capacity pack should give you hope.

teddillard
22 September 2010, 0322
it's 10 watts, yep. Fixed, thanks!

...oh and I know what TDC is BUILDING hahahahaha

Only2Jakes
22 September 2010, 0423
This sounds awesome Tony... Can't wait. I can have a guess why you dont want the original brakes and tires. Maybe your trying some regen type thing or something.. ANyways I wanna see it progress... :)

seanece
22 September 2010, 0425
Haha, you'll see but seriously, I was looking for bad tires and bad brakes. It will make more sense later. :D Also, what are the chances of 40 60Ah Sky Energy fitting in a Katana 600?

Very likely that 40 60Ah could fit. Slamming that many batteries into the bike is going to be fun to fabricate the fixtures, but it should be able to be done. Especially if you do a single or dual hub motor (http://electricmotorcycleforum.com/boards/index.php?topic=175.0) setup.

electriKAT
22 September 2010, 0743
I agree with the others. Fitting that many batteries will depend on how much ground clearance you're willing to live with, whether you've got a motor inside the frame, whether you retain the lower subframe or go without. It could be done, but not easily.

frodus
22 September 2010, 0807
40 cells? jesus, what are you putting in there?

teddillard
22 September 2010, 0820
it's gonna be DANGERous
:D

EVcycle
22 September 2010, 0840
it's gonna be DANGERous
:D

A Donut Machine? (See eariler posts.) :)

Tony Coiro
22 September 2010, 1314
Alright, I can't help it anymore. The plan is for dual hubs, probably Enertracs. I'll need two BLDC controllers, probably be the Kelly 120V 400A. I'll be using approx. 40 Sky Energy 60Ah cells. The devil is in the details and I've got some pretty devilish details planned. :D

EVcycle
22 September 2010, 1318
Matching the output of the motors for one....


Sounds cool!

electriKAT
22 September 2010, 1414
A front wheel drive moto, cool. And using hub motors means more room for batteries.

frodus
22 September 2010, 1601
Dual controllers, dual contactors, dual motors, dual fuses and you'll have to look into matching power output....

I seriously doubt you can fit that many 60Ah cells in a bike that small, but there's always saddlebags :)

Tony Coiro
22 September 2010, 1617
Dual controllers, dual contactors, dual motors, dual fuses and you'll have to look into matching power output....

I seriously doubt you can fit that many 60Ah cells in a bike that small, but there's always saddlebags :)

I think I've got a way to solve all those issues. More on that later. And so as not to get anyone's hopes up, time frame for completion is before next summer.

Tony Coiro
06 October 2010, 1740
Bringin' the noise. 1997 Suzuki Katana 600 ($400 7,500 miles) with a engine from hell. I've got a pretty crazy plan to make it work again and it doesn't involve fixing the carburetors. :D

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs601.snc4/58123_1500832118543_1166370261_31241388_7759031_n. jpg

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs264.snc4/39530_1500832238546_1166370261_31241389_907807_n.j pg

GUFF
06 October 2010, 1745
Hmm, good deal on the bike man! We look forward to hearing more about it!

magicsmoke
06 October 2010, 1811
... with a engine from hell. I've got a pretty crazy plan to make it work again and it doesn't involve fixing the carburetors. :D

Please don't let it be so crazy that it's a magnetic piston and a coil wound barrel!

Rob

Tony Coiro
06 October 2010, 1822
Please don't let it be so crazy that it's a magnetic piston and a coil wound barrel!

Rob

Crap, that was my idea. Well, since I can't do that, I guess I'll convert it to electric instead......... ;)

EVcycle
06 October 2010, 2242
Crap, that was my idea. Well, since I can't do that, I guess I'll convert it to electric instead......... ;)

Excellent decision!!!!

looks like a great project.....

Tony Coiro
06 October 2010, 2340
Should be sweet, I mean, it already has lighting bolts on the side, what more could you want? :D

cycleguy
07 October 2010, 0804
I'll need two BLDC controllers, probably be the Kelly 120V 400A. I'll be using approx. 40 Sky Energy 60Ah cells.Tony, sounds like a great project, looking forward to seeing it come together.

I do see a major issue though with your plan so far, and one that you may not have thought about yet. Since you are going to use two motors and two controllers, I'm assuming these will be run in parallel so that both motors will see the 128V from the 40 cells, which is fine. However, your batteries will have to supply enough amperage for both 400 amp controllers, which is 800 amps total. If we assume a 5C discharge rate which is pushing your SE 60Ah cells, you only have 300 amps available to drive two motors, which is only 150amps per motor. Even if we assume a 10C discharge rate which will kill your cells pretty quick, you are looking at only 300amps per motor, which is far below your 400amp target.
In my humble opinion, these cells are not going to cut it for your project. You need to look into some Headway cells at minimum, and at least 80Ah's worth, otherwise you would have to limit the controller amperage so low that it would defeat the purpose of using two motors to begin with.
Just a little food for thought.

Tony Coiro
07 October 2010, 1239
I know I will come to regret saying this and this post will be quoted by everyone saying "I told you so" but I think I have all the major technical issues addressed on this projects and have some really interesting ways around some of the issues that arise. One important thing to remember is that controller input current does not equal output current. For example, my 400A Alltrax peaks out 250A input. The power curve output side will look something like a bell curve, low at the start due to low (mean) voltage from the pulse width modulation and low at the end due to the back voltage approaching applied voltage (Lenz's Law), these two constraints cause the local maximum to happen dead center and gives the bell curve shape. So, in this case with my Alltrax, input current * 0.625 = output current at max. I don't expect to see anything over 500A battery side even with two 400A controllers. Also, based upon your rate of accelerations with any motorcycle outputting 500A @ +120V, your duty cycle is limited by physics. On a unrelated side note, Duty Cycle would be a great name for the next electric drag motorcycle.

Skeezmour
07 October 2010, 1309
That would be an awesome drag bike name!

cycleguy
07 October 2010, 1648
One important thing to remember is that controller input current does not equal output current.

I agree Tony, you'll have less current draw on the battery side but I believe you'll have more than 5/8 as much at peak.
I have no concrete facts to dispute what you've observed, but I think you may be underestimating what you out of the battery.

A quick search showed that a Curtis 80V, 550 Amp controller has a maximum output of 41.04 Kw. 41400/80= 517.5 Amps
So 41Kw of power at 80V will require 517.5 amps from the battery, less than the claimed 550 Amps but certainly not .625 of 550. I'm not trying to challenge you on this point, but just want to see you finish the project successfully.
This is an interesting subject, I'm wondering if anyone out there can share their actual experience of current draw on the battery side vs. motor current. Perhaps we can can arrive at a consensus.

Nuts & Volts
07 October 2010, 1715
Take out the lower subframe, raise the heighth of the tank and you can get 40 60ah batteries in there. Trust me there is room.

If you put the terminals facing the front of the bike. with 3 side by side (horizontal) I think you can get 8 rows vertically. Then you can fit the rest in the 2X8 behind this first grouping. I think you will be having some fun with this build. Good Luck

Nuts & Volts
07 October 2010, 1719
467468469

Fill 'er up!

magicsmoke
07 October 2010, 1721
The power curve output side will look something like a bell curve, low at the start due to low (mean) voltage from the pulse width modulation and low at the end due to the back voltage approaching applied voltage

I think in reality, because of the current limit imposed by the controller, effectively clamping the max torque, the power curve will actually be a linear rise from zero before tapering off at the end due to the back emf vs max available volts.
For a race bike, I would suggest a pack voltage capable of 'over revving' the motor so that the max torque could be maintained up to the mechanical max rpm, and then 'brick wall' rev limit it.

Rob

larryrose11
07 October 2010, 1905
Tony,
SE cells? you could cut the weight in half by using the Panasonic cells you have.
I know, I know, welding cells and such, but it would make packaging a bit easier. and someone on this site could help ya, I'm pretty sure. What about c rate on the Panasonic? What about volumetric density?

Tony Coiro
07 October 2010, 1952
Yea, magicsmoke, it should actually be linear, I was underestimating the "taper off". Larry, those Panasonic are going in my friends motorcycle and the rest either going to replace the 144V lead pack in the Porsche or going to a go kart. I will prob start up a cell welding thread soon.

larryrose11
09 October 2010, 1846
power is power
If the batteries, given their c limits and operational voltage can deliver the same power at the output power as the controller+efficiency loss, the things would be fine. This does suggest that you should get the pack voltage as high as you can.

Tony Coiro
11 October 2010, 2241
Well, design constraints in mind, I stripped down the motorcycle over the past two days, power washed the crap off of it and it's ready to go back down to Purdue with me. I am optimistic about the available space.

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs276.snc4/40144_1506603702829_1166370261_31255500_377789_n.j pg
Yea, I used the engine hoist for the frame and left the engine on the ground. That's what you call "innovation."

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs759.snc4/65993_1506719065713_1166370261_31255705_499334_n.j pg
First gas free ride

Tony Coiro
04 November 2010, 0119
I'm not dead, school is just in league with demons. Updates soon.

Tony Coiro
26 December 2010, 1903
http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs069.snc4/34813_1609487634863_1166370261_31443113_5530983_n. jpg

I've been busy, full CAD of the Katana coming soon. Holding off on dual hubs for now for a variety of reasons, plan for now it twin (so I can have a right foot) sepex, lithium polymer and a Curtis 1244-6 (80v, 600A) if I can find a place that sells them. More in the next couple days.

Nuts & Volts
27 December 2010, 1214
Tony nice work man! Anyway I can buy that CAD model off of you, it looks amazing?
Also do you need the manual for the bike? I have an electronic version I can send your way (has wiring diagrams on it)

Kyle

PS i think I have an extra left mirror laying around some where if ya need it

Tony Coiro
27 December 2010, 1234
Yeah, I'll sell it to you for free dollars/trade for the manual. Did the 89' and 97' use the same frame? I guess that wouldn't be too surprising. Also, I can't promise it's better than an 1/8" in the places where it does strange 3D stuff, especially on that top rib, so measure the actual frame if it's coming down to microns. PM me your email and the file type you'd want the frame in. (Also, offer open to anyone else with a Katana.)

EDIT: When I said free, I meant the only currency I am accepting is left mirrors for Katanas. Seriously. Cuz I need one.

jpanichella
27 December 2010, 2138
Nice Tony, any reason for doing a dual sepex instead of dual PM?

Tony Coiro
27 December 2010, 2152
Nice Tony, any reason for doing a dual sepex instead of dual PM?

Cost and ability to change the field strength.

jpanichella
27 December 2010, 2156
I see. Do you plan on doing any sort of series/parallel switching? What kind of capacity/voltage LiPo pack are you planning on?

Tony Coiro
27 December 2010, 2210
I'd really like to do series/parallel switching to test it's impact on performance. It reminds me of the transmission thread, it could argue with myself all day on whether or not it would help and get no where, so I do really want to try it. Voltage depends on if I can find that Curtis controller anywhere, it's 80V nominal. Capacity(and the whole project) depends on my budget, which will vary based almost entirely on if I keep my full ride, which I'll find out later this week.

Tony Coiro
29 December 2010, 1146
http://sphotos.ak.fbcdn.net/hphotos-ak-ash1/hs742.ash1/163410_1613118845641_1166370261_31450279_1036121_n .jpg

Just screwing around until I can get back down to school/machine shop.

Tony Coiro
31 December 2010, 1528
Well, I have started on the slippery slope of rash financial decisions. Just ordered two D&D 170-512-0005 motors. (http://www.evdrives.com/dd_motors_170-512-0005.html) It was hard to argue with the price, I like the flexibility sepex gives and using two short motors instead of one long one gives me 76 pounds of thermal mass and lets me keep a right foot. (Might try parallel/series switching.) I am CAD-ing out the LiPO modules right now, things are looking good in the model and the preemptive estimate based on the model is 419 pounds, all things included. 24s6p (approx 80-90V, 30Ah, although I will the batteries in the 30-90% SOC at all times for safety.) Going to start with one Sevcon PowerpaK 425A controller with room for a second later on. Lastly, I am going to be doing a lot with DAQ and on board computing, thanks to National Instruments and LabVIEW.

DaveAK
31 December 2010, 1642
Looks like those motors come with speed and temperature sensors, right? Pretty cool. I'm using the larger ES-10E-33 which doesn't have that stuff. I'm going to put a hall sensor on the output somewhere though. I'm also going all out with DAQ and on board computing, but no NI or LabVIEW. If you come up with anything good as far as CAN protocol for the Sevcon then let me know! That's my on going project. I've already hooked mine up and got some data from it, but it's useless until I know what it means. :)

RichL
03 January 2011, 0900
Tony, very cool project.
What is the make/model for the lipo batteries?

Tony Coiro
03 January 2011, 1029
The current plan is to assemble modules of 6s6p (24V 30Ah per module) 30C Turnigy Lipo from Hobby City with room for an additional, identical pack for longer trips or the times I was to draw 1800A continuous. ;)

teddillard
03 January 2011, 1037
surely you can't be serious!

:p

Remotecontact
03 January 2011, 1105
Just go 8p so you can use my modules.

Tony Coiro
03 January 2011, 1133
Remote, what's the size, weight of your modules? Will they have balance wires? Size of the output wires? I'll see if they will fit in my model.

Tony Coiro
10 January 2011, 1959
http://sphotos.ak.fbcdn.net/hphotos-ak-snc6/hs076.snc6/168614_1636550071407_1166370261_31488570_2928162_n .jpg

The twins have arrived. I gotta hurry up and get these mounted, I hate losing to Ted. :D

Tony Coiro
12 January 2011, 2027
(Shameless bump)

http://sphotos.ak.fbcdn.net/hphotos-ak-snc6/hs064.snc6/167408_1638978612119_1166370261_31492723_4156123_n .jpg

Motors positioned (with cardboard and plywood.) For $250 each, these motors seem ideal. No fairing chopping or motors sticking out the side. Just need to get metal stock tomorrow from the machine shop and I'll have these mounted soon. Have a much simpler solution in mind for it which really utilized the stock motor mount. I'll reply to myself again in a couple days with more.

DaveAK
12 January 2011, 2031
I'll keep pretending I'm you then. :D

(Oh, and I updated my Sevcon CAN controller thread, in case you want to pretend to be me. :p)

Nuts & Volts
12 January 2011, 2055
For $250 each that is a steal, no wonder you're going LiPo. I am jealous. My next build wont be for a while I think. I need to save up to play with the big boys!
Aluminum machined motor mount?

Tony Coiro
12 January 2011, 2131
Yup, I'm picking up stock tomorrow, hopefully I'll be able to mill them before this weekend, shop is only open weekdays. Also *spoiler alert* it looks like I'll be going LiPo/TS/CALB/GBS now. I got this project classified as "research" so I'll be using my motorcycle as a test bed for some of the EV stuff Purdue is doing. :D

Nuts & Volts
12 January 2011, 2158
You lucky dog! Let us know what you discover during this research. I think LiPo is definitely the way to go, just because the bike will be a dog with large prismatic cells and you might not be able to fit that many either. But LiPo is no easy way to go...

Tony Coiro
12 January 2011, 2224
But LiPo is no easy way to go...

It's OK, I have a beard. I can handle anything.

DaveAK
12 January 2011, 2247
FU TC. FU and your "research" :mad:

(Do like your choice of motors though. Cute little buggers. ;))

Square Wave
13 January 2011, 0402
I've been considering making a pack from a bunch of cheap little LiPo's, too. Keeping in mind that I'm new to the electrickery part, I am a little worried about finding a charger that will do the job without busting the bank. So Tony (and anyone else), how are you going to charge your high power LiPo pack?

Nuts & Volts
13 January 2011, 0926
I've been considering making a pack from a bunch of cheap little LiPo's, too. Keeping in mind that I'm new to the electrickery part, I am a little worried about finding a charger that will do the job without busting the bank. So Tony (and anyone else), how are you going to charge your high power LiPo pack?

Search on Endless-Sphere. They do it all the time. Some chargers can evern do 14s which is like 58.8V fully charged. Take 2 of those (http://endless-sphere.com/forums/viewtopic.php?f=14&t=23362) and charge a 20s pack in 2 10s bricks. Not sure how fast you can charge them maybe at like 5-10 amps with a 10s pack. You will also need a big power supply (10.5-29V).

You can also you use a a regular charger and have a BMS balance the series strings.
Other options may exist. LiPo charging is more involved but is probably not that much more expensive then some options (charger, BMS kit).

My 2 cents
Kyle

EVcycle
13 January 2011, 0948
I have a matched pair of 20 tooth #40 motor sprockets if you want them for your tie together chain.


Ed

Remotecontact
13 January 2011, 0955
Remote, what's the size, weight of your modules? Will they have balance wires? Size of the output wires? I'll see if they will fit in my model.

They're 5 x 7.5 x 9.25. 6s8p with a 7pin 30a powerpole balance port, 2awg discharge leads in wire grasps with 180amp Powerpoles. I run 25C cells. I'll email you the CAD. If anybody else is interested in "plug and play" lipo modules let me know.

jpanichella
13 January 2011, 1016
They're 5 x 7.5 x 9.25. 6s8p with a 7pin 30a powerpole balance port, 2awg discharge leads in wire grasps with 180amp Powerpoles. I run 25C cells. I'll email you the CAD. If anybody else is interested in "plug and play" lipo modules let me know.

I think something like that would even warrant it's own thread. It seems like lipo is generating a ton of interest.

Tony Coiro
14 January 2011, 1423
All the hard work on the virtual design paid off in a huge way this afternoon. Both motors are mounted and there are SEVERAL locations with a 1/8 inch of clearance (or less!!!) I really couldn't be much more excited. I'll post some pictures later this evening.

Tony Coiro
15 January 2011, 0923
http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs069.snc4/34822_1641289229883_1166370261_31497109_1158802_n. jpg

http://sphotos.ak.fbcdn.net/hphotos-ak-ash1/hs750.ash1/164104_1642048368861_1166370261_31498220_1648528_n .jpg

http://l7.sphotos.l3.fbcdn.net/hphotos-l3-snc6/hs043.snc6/167339_1642048688869_1166370261_31498221_1027385_n .jpg

3 locations on the frame with an 1/8th of an inch clearance or less and the bolts for the field windings are actually tangent. :D

harlan
15 January 2011, 0934
Nice! Its coming together!

EVcycle
15 January 2011, 1726
Very Cool.

Tony Coiro
24 January 2011, 2142
While waiting for my results of my attempt to genetically engineer a tree to grow money, I started working on this:

http://sphotos.ak.fbcdn.net/hphotos-ak-ash1/hs788.ash1/167827_1654466839315_1166370261_31523220_3306043_n .jpg

Just ignore the readings on the gauges, they're dummy values. What other parameters would you guys consider useful?

Nuts & Volts
24 January 2011, 2212
Lookin good. I got three things. Make the HP gauge toggle between kW and HP maybe, add a numerical kWH value so you can tell more accurately than the bar, and add a odometer to the system. Maybe a clock, or timer. Sometimes its nice to see how long you have been riding.

Skeezmour
24 January 2011, 2348
I'm a fan for low voltage cell displayed or even an indicator light. Like your motor temp one.....keep it up...and let me know how that money tree works out.

DaveAK
04 February 2011, 1409
Hey Tony. Does EVDrives offer the speed sensor as shown in one of the pictures and the PDF drawing? Did you get them or not?

Tony Coiro
04 February 2011, 1837
Mine did not come with speed sensor wire output.

Tony Coiro
17 February 2011, 1312
https://s-hphotos-ash1.fbcdn.net/182234_1685414772994_1166370261_31578868_5340761_n .jpg

Front plate for the dual controllers and DC-DC converter installed and motors chained together. I think I'll git er done by spring. :D

frodus
17 February 2011, 1401
did you check to see if the front forks clear the front plate under full compression? Allow some flex, because under hard stopping, they will flex towards the frame.

Tony Coiro
17 February 2011, 1422
did you check to see if the front forks clear the front plate under full compression? Allow some flex, because under hard stopping, they will flex towards the frame.

Helll yeah, you must have mistaken this for "amateur hour." :D It doesn't look like it in the picture but the plate is flush with the inside of the front ribs, the picture makes it look further forward than it is.

teddillard
17 February 2011, 1444
Helll yeah, you must have mistaken this for "amateur hour."

nah, THAT'll be when you get on this thing for your first ride! LMAO (PLEASE tell me it ain't gonna be in a hall... :O)

Skeezmour
17 February 2011, 1546
shhh....don't give away his testing grounds.

Tony Coiro
17 February 2011, 1714
Actually, officially, I am not allow to test in the physics building anymore, something about finding tire skid marks on a wall.......... :D

Tony Coiro
02 March 2011, 2120
https://s-hphotos-snc6.fbcdn.net/181896_1705015943011_1166370261_31609272_131475_n. jpg

Little update. The terminals on the Sevcon are soo freakin close to each other.

DaveAK
02 March 2011, 2126
Little update. The terminals on the Sevcon are soo freakin close to each other.
Yup. I can atest to that. :) Still, it seems to be a pretty good controller. I'll be ordering a couple in the next week or so.

Tony Coiro
02 March 2011, 2135
You know the Sevcon can control two motors at the same time independently right?

DaveAK
02 March 2011, 2139
You know the Sevcon can control two motors at the same time independently right?
No, I didn't know that. I've not noticed anything about it in the manual. Tell me more. :) Do you have info on that, such as a page number that I've not paid enough attention to?

DaveAK
02 March 2011, 2141
How can it drive them independently if you need them going at different speeds or directions?

Tony Coiro
02 March 2011, 2149
*frantically begins searching*

A friend of mine told me it could and I was under the impression that's what the terminal in the bottom right corner labeled "S" did.

DaveAK
02 March 2011, 2152
A and S go to the armature, F1 and F2 go to the field. There is an unsued R terminal that is jumpered to the B+. Maybe this could be used to feed another armature independantly from S, but you still wouldn't be able to independently adjust the field.

Tony Coiro
02 March 2011, 2205
Sounds like what you're saying is tomorrow is the day where I am gonna finally have to get around to reading that 60 page manual..........

DaveAK
02 March 2011, 2207
'fraid so. And slap that friend of yours around the head. :D

DaveAK
02 March 2011, 2211
It does have a dual traction setup, but you still need two controllers.

Nuts & Volts
02 March 2011, 2216
My guess is the Sevcon is set up to run two motors on different axles. So you keep the field the same on both motors which keeps the motor constants (RPM/V) the same. This keeps both axles (front and rear) at the same speed which is desirable in a vehicle. But having two different armature outputs would allow you to send different amounts of current to each motor and generate different torque. This works because the motors will have to be at the same voltage due to one controller (one PWM circuit) being present so they will remain (or want to remain) at the same speed.

But Motor A may be loaded more (ie more traction). This slows Motor A down and the back bemf of Motor A drops. Now that allows Motor A to draw more current which produces more torque and speeds up Motor A. This continues until Motor A's speed and bemf matches that of Motor B which is the less loaded motor.

If Motor A is on the front axle and Motor B is on the rear and you have a weight distribution of 54% front and 46% rear. On level ground the front axle will have 8% more traction than the rear axle. This puts 8% more load on Motor A which will end of drawing 8% more current than Motor B. If you want the motors to age the same you should run 8% more cooling through motor A :)

Wow I kinda pulled that out of a hat but I think I pieced it together right

DaveAK
02 March 2011, 2223
Everything I've seen in the manual points to two controllers, with CAN communication between a master/slave. That's my story and I'm sticking to it. :)

Nuts & Volts
03 March 2011, 0920
Anybody want to second my explaination?? I really curious if it works out correctly.

DaveAK
03 March 2011, 0942
Anybody want to second my explaination?? I really curious if it works out correctly.
It sounds plausible to me, but I have no where near the expertise to comment, other than to say you'd have to make sure the field resistance was identical, (within tolerances), for each motor, as that's a critical setup component of SepEx motors.

Nuts & Volts
03 March 2011, 1053
It sounds plausible to me, but I have no where near the expertise to comment, other than to say you'd have to make sure the field resistance was identical, (within tolerances), for each motor, as that's a critical setup component of SepEx motors.

Im in agreement there. As I have seen travis mention on other threads, it is important to understand the different in resistances when running multiple motors on a single controller. But all the dual agni's setups should show that it is definitely possible

DaveAK
31 March 2011, 1038
Tony, any update? I've just ordered two 48V Sevcon controllers for my next project and was wondering how you were getting on with this? I'm going to have mine both controlled by a microcontroller with a closed loop to speed sensors on the motors.