# dyno testing EV set ups



## 2cycle (Jul 2, 2009)

With my background in IC engines it seems strange to me that it so hard to find good dyno test data. Why is that? Are there no dyno facilities that can set up an EV motor on their test stand and flog it for a while to get things dialed in. The snowmobile industry has a dyno shop from New York that does just this same thing for snowmobile enthusiasts, they just test what you bring them but you can make all the adjustments you want while it's hooked up to try and better the performance to suit your riding style.

I guess my real question is SHOULD there be one. Is there enough DIYer's to make the investment in a 2000 lb/ft dyno for electric motors? If so, I have no problems pulling the trigger on that project, It would likely cost about $500,000 to get set up properly. I was a dyno operator for 10 years so getting into that again wouldn't bother me at all and I have a fair bit of knowledge on how to properly set one up it's just the controls that become different with electric vs ICE. 
I realize the big cost would be to have on hand many components like controllers, inverters, motors and all associated wiring, but the real focus would be on providing a place for the DIYer to send his/her motor and controller to get it "tuned" for their set up. The more threads I read the more I realize that some components don't produce what's advertised or someone gets there DIY EV going only to find out after a 100 hours of gettings things fit that it either doesn't have enough power for them or somethings just not right in the controller settings. 

My biggest questions are about performance, I know I read someone elses thread where someone mentions not having the power curve graphed out like some other company did. If the motor can take 800 volts even if just for a drag race, I wanna know. The manufacturers just advertise what they want you to know (sounds familiar) but to be honest I don't think even they know half the time just how much it can take for short periods because it wasn't made for that it was made to last for years.

I think of this as an independant testing facility that provides a subscrition based web site to archive it's testings and maybe a daily blog about the goings on. The snowmobile test facility that I mentioned even has a web cam in the control room and one in the test cell so for a $20/yr subscription fee you can view and listen to the testing going on daily. It's also a place where small aftermarkets that make a product they want the world to know about can test there. I have seen a company with a great product become instantly famous because they tested there and the whole world watched in while it performed flawlessly on the web cam and the next day the manufacturers phone wouldn't stop ringing and the cash register didn't stop filling with money. The value of that kind of advertising is priceless.

So if anyone has any info I'd like to hear it. Maybe someone already has this angle covered, if so I'd like to know for my own knowledge. Maybe you have an idea to help this thing happen for real - I'm all ears.


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## AmpEater (Mar 10, 2008)

I was just thinking about this exact concept.

Beyond tuning I can see it being invaluable for thermal data....what does the temperature/time graph look like for a controller running at 100% output? How long can you run at X amps before the duty cycle gets cut back? Etc, etc.

Even to simply be able to observe brush arcing under full load conditions safely would be huge.

Considering the amount of money many of us have into our setups a few minutes of operation in a controlled environment could provide hugely valuable information. Plus the ability to test and re-test in a reproducible fashion after upgrades and changes....with printouts to compare side-by-side....it would really take the art of EV building to the next level.


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## 2cycle (Jul 2, 2009)

AmpEater said:


> I was just thinking about this exact concept.
> 
> Beyond tuning I can see it being invaluable for thermal data....what does the temperature/time graph look like for a controller running at 100% output? How long can you run at X amps before the duty cycle gets cut back? Etc, etc.
> 
> ...


I'm glad to see someone else is on the same page as me. The data loggers we now use for ICE can easily be used for collecting data on an electric motor. The ones we use are highly configurable and they have 2GB of memory.


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## Dalardan (Jul 4, 2008)

Tesseract has publicly stated that he mounted a Warp 9" on a dyno to testbench his controller. The data he showed us are more oriented on his controller, but maybe he could test some motors with his controller if a deal is made with him. But I do think it's now better for the DIYers that he finishes his controller before doing such stuff.

There are already a lot of dyno shops ready for people like you and me. I'm living in an area 5 hours north of Montreal, Canada, really far away from any real racing world, and we've got a compagny with a Dyno specialised in ICE car turbo installations. Also, a local high school has recently gotten a $350,000 dyno to teach future mechanics how to do government pollution testing and stuff like that. At my university, we've got a 7" water brake dyno that can handle up to 60hp, witch should be enough to have fun with electric karts and motorcycle motors, and our Formula SAE team has a car sized inertia dyno that is getting instrumented at the time we're writing. Maybe ask a local university with engineering students? This database could be an awesome project...

I do think a dyno isn't something really rare these days, unless you do wanna harness a montruous drag machine, and it could be possible to make a deal with a local shop.


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## 2cycle (Jul 2, 2009)

There are a few problems with testing EV motors at an ICE dyno facility, 1- they don't have the dyno to handle the low rpm torque electric motors make mostly because any lower cost dynos are water brakes and water brakes need rpm to build enough brake pressure, I know because I ran water brake dynos for many years. My next door neighbor has a Superflow 901 dyno just like the 2 I use to run and they can handle a 2000 hp car engine but when you get even 900 hp it can't hold the rpm below 4500 rpm because it doesn't have enough pressure built up yet. 
2- there test stands are not made to hold EV motors.


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## Tesseract (Sep 27, 2008)

2cycle said:


> ....
> 2- there test stands are not made to hold EV motors.


We have a 250hp marine dyno that uses a gear pump which bolts right onto the propshaft to force hydraulic fluid through a variable restrictor nozzle. It's very elegant and seems to be accurate just going by the electrical power to the motor (factoring in it's published efficiency) versus the pressure/rpm measured by the dyno.

The test stand we use? A block of aluminum bolted onto the rear bearing plate of the motor so along with the gear pump up front it can rest level on the ground 

Granted, this isn't a *vehicle* dyno, but Dalardan's characterization is correct: we got the dyno to test controllers, not vehicles. Still, we have already tested a number of other controllers (usually causing us to  hysterically) and have three different motors that can be bolted on to the dyno (WarP 9, Kostov 144V 9" and Kostov 192V 11") so once we wrap up the beta testing of the controller we want do a little motor comparison of all three for the EV community.


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## 2cycle (Jul 2, 2009)

Tesseract said:


> We have a 250hp marine dyno that uses a gear pump which bolts right onto the propshaft to force hydraulic fluid through a variable restrictor nozzle. It's very elegant and seems to be accurate just going by the electrical power to the motor (factoring in it's published efficiency) versus the pressure/rpm measured by the dyno.
> 
> The test stand we use? A block of aluminum bolted onto the rear bearing plate of the motor so along with the gear pump up front it can rest level on the ground
> 
> Granted, this isn't a *vehicle* dyno, but Dalardan's characterization is correct: we got the dyno to test controllers, not vehicles. Still, we have already tested a number of other controllers (usually causing us to  hysterically) and have three different motors that can be bolted on to the dyno (WarP 9, Kostov 144V 9" and Kostov 192V 11") so once we wrap up the beta testing of the controller we want do a little motor comparison of all three for the EV community.


My point was auto engine dynos are not friendly to anything but ICE power curves and the mounts are very limited. What you have works great for you and that's what really matters. But for a true testing facility open to public and all their different schemes one needs to have a very universal type mounting system that can have a motor bolted on and ready for testing within minutes. My neighbor with the SuperFlow dyno can take an engine from the back of his pickup to running on the dyno in 15 minutes. You can't spend time fabricating new mounts every time you have a new engine that's why their set up is geared so they can mount any auto engine within minutes, I just wanted the same for motors.

I have thought about the chassis dynos, but there are tons of them everywhere and there's no modifications needed just drive the car on and strap her down. Plus at that point the fitting work is all complete in the car and it's too late to make changes without spending lots of extra time now. I'm more concerned about getting the components matched up ahead of time and maybe testing other combinations with components I have in the test cell ready to go. 

The best dyno that I can think of is the eddy current dyno, very controllable and super accurate. We use this type of dyno for any and all certifications such as emissions on ICE. The downfall is their cost, or should I say the controllers cost. I just got a quote today for a refurbed unit with all new controls at $70K. The up side to them is I could test any EV motor out today and most that haven't come out yet. It has the ability to hold a WarP 9 or 11 or 13 at 500 rpm at full tilt amperage. There isn't a water brake dyno built that can do that. 

Like someone pointed out before it's about learning the limits of your given set up. When things are going to start going bad according to what temp etc. . We could do what we call in the dyno world as life cycles. We could program a complete real world scenario of hills and fast areas and stop and go for as long as needed to satisfy your curiosity. http://www.youtube.com/watch?v=8DYl4mD_620 this is a Honda F1 engine running a life cycle test that is programmed into the computer to simulate an entire race so they know before it ever hits the race track that it can at least survive a race. I think putting an EV motor through it's paces on a dyno will show a few things that we may otherwise miss.

This is taken from another thread to use as an example of the questions that could be answered, this was from Bowser330, 

...When looking at the motor graphs, Amps decrease with RPM, so with a locked ratio this means, the faster you go (mph) the less Amps you can pull from the pack...So can you please help me understand how the dragsters like S10-smokescreen and the White Zombie can extract max amps for 11 seconds?

I guess i was under the impression that they could only extract max amps up to a certain rpm...

If it is because those two example dragsters have high voltage setups which push up the overall rpm curve, then I guess i understand...

Also i am assuming that the motors still have a structural maximum rpm of about 6000 before they break apart...Is there a way to increase that? END OF QUOTE

I would love to say, that's a great question. Lets bolt up a motor like theirs and controller like theirs and see what happens. And while were at it let the whole world watch along on a web cam. I used to love watching real time dyno testing online. It keeps you informed and lets others watch along and maybe help out as I did with the dyno web cam I speak of. I was listening in during a test session and heard them trying to figure out what fuel line to use on a high pressure 250 psi fuel line so I picked up the phone and dialed the dyno shop and gave them the part number of the stuff they were wondering if it existed.


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## Bowser330 (Jun 15, 2008)

tesseract said:


> ....we have already tested a number of other controllers (usually causing us to :d hysterically) and have three different motors that can be bolted on to the dyno (warp 9, kostov 144v 9" and *kostov 192v 11"*) so once we wrap up the beta testing of the controller *we want do a little motor comparison of all three for the ev community*.



I really am interested in seeing that data!


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## 2cycle (Jul 2, 2009)

No kiddn, show us some numbers Tesseract. We want to see some graphs and hear about those hilarious trials and tribulations of trying other controllers. I would really like to know what components to stay away from and which ones are worth their salt.


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## Tesseract (Sep 27, 2008)

2cycle said:


> ...But for a true testing facility open to public and all their different schemes one needs to have a very universal type mounting system that can have a motor bolted on and ready for testing within minutes....


Well, that's where you have it made with electric motors: the same bolt circle and shaft size is used on all 3 of the motors we have, and my understanding is most everyone in the EV motor biz just copied what ADC decided on (even though the shaft size is a bit small given the amount of torque a WarP 11 at 1000A+ can deliver).

As for an adapter, we did CNC a block of aluminum to join the bolt circle of the marine dyno to that of the motor, but to mate the shafts we just used an off-the-shelf Lovejoy coupler from McMaster-Carr. Later today when I am at the shop I'll take some pics. 




2cycle said:


> The best dyno that I can think of is the eddy current dyno, very controllable and super accurate. ...


Eddy current is easier to control and has a lower RPM limit but still converts all of the input power to heat and has a minimum RPM requirement just like the water brake. Instead, take a look at the motor/generator setup that the Belktronix guy uses for a dyno:

http://www.belktronix.com/dyno.html

_That _is the smart way to build a dyno for testing electric motors. The battery pack (or AC line, even!) only has to supply the power lost to inefficiencies.




2cycle said:


> ...We could do what we call in the dyno world as life cycles. ... a Honda F1 engine running a life cycle test that is programmed into the computer to simulate an entire race so they know before it ever hits the race track that it can at least survive a race.


They're called "load cycles" in industrial engineering, but I agree that this sort of testing is the most useful. Our marine dyno is not such a good candidate because it uses a manually operated valve to adjust loading. A dyno in which the load is electrically adjustable, like the eddy current and motor/generator types, is much easier to program load cycles into.




2cycle said:


> This is taken from another thread to use as an example of the questions that could be answered, this was from Bowser330, ...


It's like deja vu all over again... Except for the one about how to make the motors withstand higher RPMs, I already answered those questions for Bowser330 in the same thread...


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## Tesseract (Sep 27, 2008)

2cycle said:


> No kiddn, show us some numbers Tesseract. We want to see some graphs and hear about those hilarious trials and tribulations of trying other controllers. I would really like to know what components to stay away from and which ones are worth their salt.


Uh-huh... and you all would believe me when I posted results that called into serious question the claims made for some other company's controller? What if the 1kA controller that is just about to exit beta testing ends up smoking the Zilla Z1K in every aspect and even gives the Z2K serious competition in every parameter except peak current? You think the Zilla lovers (of which I am one, oddly enough - nothing but admiration for that design!) won't come down on me like a ton of bricks? Hell, even the Kelly lovers (hard to believe there are any?!) got all riled up when I opened up a smoked KDH12600 and exposed its guts for all to see. 

Soooo... we'll publish dyno data for different _motors_, but I don't think it is in our best interest to do so for different _controllers_.


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## 2cycle (Jul 2, 2009)

Well you have a point with the controllers. You are making your own so your competition. It's just like reading the GM ads on how much more power they make than the Toyota, and then Toyota gets mad about it so they highlight a advantage they have over GM and it keeps going round and round. The snowmobile dyno I mentioned went through exactly that 20 something years ago when most companies said "we'll make this and nobody will be smart enough to figure out that it isn't making the power we claim how could they possibly know." Then came along this shop that would test anything you brought to them and they even published it as a monthly news letter of sorts that quickly became the gospel of all gear heads in the industry. He even had a famous Cycle World Magazine technical writer writing tech articles as filler material and I must say that writer was very good and still to this day writes some of the best tech articles.
I don't think of it as bashing a company, it's more like forced accountability. If they know that the world is going to see the results with their own eyes they will make damn sure they advertise achievable results. When they say their controller is a 1000A controller it should be achievable. This type of advertising from the suspect controller makers sounds just like the BS engine builders years ago. It showed a spike of 155 hp one day during testing so it gets advertised as a 155 hp engine when in reality it's a 140 hp engine as it's sold to the public without ever a chance of making 155 hp.

And yes, if you showed proper test procedure and systematically eliminated all adjustment errors that could change the end result I would have to say the educated EV community would likely believe you. So does this mean you will carry out any tests we want for a fee? I couldn't care less whos feelings get hurt. I've been in development long enough to know you ALWAYS have a few stumbles in the road during development and to get to the top one sometimes must back track to find the best route to the top. I'd be lying if I said I haven't blown up $50k in engines during testing, but in the end it was worth it.


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## 2cycle (Jul 2, 2009)

Tesseract said:


> Well, that's where you have it made with electric motors: the same bolt circle and shaft size is used on all 3 of the motors we have, and my understanding is most everyone in the EV motor biz just copied what ADC decided on (even though the shaft size is a bit small given the amount of torque a WarP 11 at 1000A+ can deliver).
> 
> As for an adapter, we did CNC a block of aluminum to join the bolt circle of the marine dyno to that of the motor, but to mate the shafts we just used an off-the-shelf Lovejoy coupler from McMaster-Carr. Later today when I am at the shop I'll take some pics.
> 
> ...


I'm use to the SuperFlow console were it says "life cycle" next to the selector knob. 

I looked at the dyno in the link. Yes AC dyno's are the very best, just very expensive controls. I ran a $750K dyno for an OEM that was custom built for chassis testing a 4 wheel drive ATV. It had 3 seperate AC motors in it and had a control unit the size of some small countries. AC dynos are nice where you can motor the test subject to measure parasitic losses. 
I have run most every type of dyno (AC, eddy current, hydraulic drum, water brake, friction brake) and my choice would be eddy current for it's price and control and simplicity. If I were doing durability testing then a water brake like SuperFlow is best bang for the buck. If money was no object then AC all the way for all testing. The eddy current dynos I'm looking at can hold 1000 lb/ft as low as 200 rpm which there is no reason to test below that anyway.


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## Tesseract (Sep 27, 2008)

2cycle said:


> ...
> I don't think of it as bashing a company, it's more like forced accountability.


You and I are on the same page, but you'd be amazed how many other people aren't! I totally agree that the EV world is in the same need of standardized testing as the audio amplifier world needed back in the 70's (and speaker manufacturers are in need of to this day).




2cycle said:


> And yes, if you showed proper test procedure and systematically eliminated all adjustment errors that could change the end result I would have to say the educated EV community would likely believe you.


Maybe, though I still think that an independent testing facility, as you proposed, would be much more palatable to the community rather than a controller manufacturer dyno testing controllers (or a motor manufacturer dyno testing motors).

Seriously - no matter how rigorous, say, NetGain was testing their WarP motors against Kostov equivalents, not a single person here (me included) would 100% believe their test results (unless they showed the Kostov's to be superior in every way...  ).

As a nascent controller manufacturer, we would have the same credibility problem testing other controllers. I imagine no one would doubt it if our 1kA controller beat the snot out of a 500A Kelly/Curtis/Alltrax/Logisystems, but what if it was still delivering the ol' smackdown to, say, a 1000A Logisystems? Or, even worse, the holy grail of controllers: a Zilla Z1K? That'll start a foodfight, alright.




2cycle said:


> So does this mean you will carry out any tests we want for a fee?


The dyno is owned by Rebirth Auto, not evnetics, and while they might be willing to do specific tests for people for a fee, we will be using the dyno to do some tests that may be interesting to the community for *free*... Might as well see what you can get for nothing, first, right?

EDIT: oops - apparently evnetics owns the dyno; rebirth auto owns the motors. Well, it's refreshing to see I am staying on top of where all this money is going to...


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## Dalardan (Jul 4, 2008)

Hum... I was just thinking about the thermal challenge of dyno testing motors. For the motor in itself, it's not of a concern as the purpose of this dyno testing is to find the design limitations of the product. I was more wondering about the batteries and controller setup.

About the controller, for DC setups, you'll need to find one heck of a controller to take over several minutes of full power. I do think it's worth waiting for Tesseract's and Qer's product for those continuous duty testing. So, by this time, we should be able to see what informations they'll share with us, especially about thermal management and power output. Up to now, they showed us that their unit would be overkill for most motors, therefore not beeing the power bottleneck, and beeing perfect for this task. Wait and see.

For AC setups, unless Esticher's VFD drive is ready, you'll need to use the motor/controller combo on the dyno. I do naively think they are rated to output the most of each two, but if those testings are for ultimate power output, maybe the controller will be too conservative. 

Have you thought about the power supply? At least, it should be able to deliver continuously 1kA, as it's the highest rating I've seen on a controller (and it was peak rating, thus for extensive testing, the battery pack needs to be overkill). This would allow it not to be the power bottleneck, therefore the motor would be the only powerlimiting factor in the line. I have absolutly no idea as what should be the voltage of the battery pack. Maybe a 300ish pack that could be separated in two and put in parallel to give a 150ish pack?

About the dyno, I still do think that $500,000 is a quite big investment if you're only testing those electric motors... If you already plan on openning a dyno shop, well, it's up to you. I do think it would be far more cost efficient to simply rent dyno time with a compagny that have such a dyno you spoke about. Money could be spent on getting spare motors of each type, those which could be sent to DIYers if still in good shape after the testings. Well, it's just an idea, I don't know at all what are the business opportunities in your area.

Finally, I do agree that there is a need of independant testing in this quasi-monopole controlled be NetGain, Kostov, ADC and some smaller ones I don't remember. But, as Tesseract pointed it, a motor manufacturer can't be the reference for motor testings. Continue to evaluate the different possibilities, it would be a great project for the DIY community.

Dalardan


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## Drew (Jul 26, 2009)

It sounds like you guys are after something which doesn't really exist, there aren't any dynos that I'm aware of that deal with stalling torque etc.

If you wanted to develop something like this though it would be quite easy to do something in a bit of a back yarder vein. There are a number of torque sensing devices available for use on cars for testing that use a calibrated drive shaft which is then measured for end to end misalignment to measure torque. If you combined this with a tachometer then you can easily put together a dyno that can measure torque and power very effectively.

I'd recommend car front brake discs as the load if you want to be able to measure torque at 0 RPM onward, if you used a brake setup or two bolted onto machined hubs and then actuated the hydraulic circuit either with a solenoid for computer control or simply with a lever for hand control you could easily measure the power and torque from 0RPM to no load speed. 

As an additional benefit if you used components from a large and relatively cheap car then consumables would be extremely cheap as well, and if you can't achieve the right load then you simply add more brake discs to the circuit.


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## Tesseract (Sep 27, 2008)

Dalardan said:


> ...I was just thinking about the thermal challenge of dyno testing...
> ...
> About the controller, for DC setups, you'll need to find one heck of a controller to take over several minutes of full power.


I think I know where to find one... 

Okay, seriously... most of the latest runs posted in the "New controller prototype" thread were done with my "test unit", which got the job because its enclosure/heatsink was damaged by a tool path error during machining. It doesn't have the water cooling loops drilled out, among other things, so it's only good for testing worst-case natural and forced convection cooling runs. That said, even with just fan cooling alone it is more than capable of exceeding the amps vs. time limits of the WarP motors (e.g. - 450A for 5 minutes). Once again, we have no desire to destroy any of our motors at this time (for the obvious reason of it costing us lots of money... ).




> Have you thought about the power supply? At least, it should be able to deliver continuously 1kA, as it's the highest rating I've seen on a controller (and it was peak rating, thus for extensive testing, the battery pack needs to be overkill).


Ahem... 




> Maybe a 300ish pack that could be separated in two and put in parallel to give a 150ish pack?


Yep - I finally got around to cobbling together a simple variac based charger which should be able to charge and equalize packs all the way up to 25 batteries with up to 25A of current. So, 300V nominal tests are coming up. 




> About the dyno, I still do think that $500,000 is a quite big investment if you're only testing those electric motors...


It is, to put it bluntly, completely unaffordable. We paid $1500 for our slightly used marine dyno and it seems to get the job done. There just isn't a big enough market (now anyway) for EVs to justify investing $500k in a single piece of capital. We'd like to actually make money selling controllers, not simply service an overwhelming debt burden (and believe me, we have enough of that to service already just from developing the thing).




> If you already plan on openning a dyno shop, well, it's up to you. I do think it would be far more cost efficient to simply rent dyno time with a compagny that have such a dyno you spoke about. Money could be spent on getting spare motors of each type, those which could be sent to DIYers if still in good shape after the testings.


This makes perfect sense to me. A bunch of interested persons could get together to buy the motors and controllers (knowing they will likely be tested to destruction) then send them to an independent dyno lab.

Anyway, the EV community is definitely lacking in hard data on the motors and controllers it uses so the more we can all do to rectify that situation the better off everyone will be. If nothing else, it will stop people from making such monumental mistakes like thinking a 48V pack, a 200A Kelly and a 6.7" motor will have enough power to do a 20 mile commute with 2 miles of that uphill, every day (and not be required to stay in the bike lane....  )

Yeah, that's a lot of time and money invested in a conversion that has absolutely no chance of success and which only serves to prove to the public that EVs are pathetic, slow-ass vehicles that are absolutely no fun whatsoever to drive... Not helpful IMO. Okay, rant over. Carry on!


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## 2cycle (Jul 2, 2009)

I didn't mean the $500K was for just a dyno, I think for $25K I can buy and then modify a nice used unit with all the good controls and data collection. I think $500K is what an entire outfit would cost. That includes a shop in the part of town with 3 phase power (that doesn't happen everywhere and around here it $3000/mnth lease), all the popular motors currently at a couple thousand a piece and some future ones with good DIY potential, all the common controllers, tons of batteries and cabling, all needed elctrical testing equipment,etc etc. 

For that matter it may all be had for $150K, I don't know for sure, but from the sounds of it just the battery packs alone will cost 10's of thousands for 2 complete huge packs. Remember I don't really need to supply this stuff it would just be nice to have it on hand in case the customer has problems with his equipment then we have a spare right there and it doesn't waste a day, at first it would be a run what you brung set up and if your pack fails or controller fails or motor fails it costs you dyno time still the same. Remember I've run a dyno shop before and things aren't cheap. The data aquisition software alone is $10K new. I can find a lot of used stuff to build what I want, and no I wouldn't turn away ICE customers unless the EV testing was consuming all of my time, which I don't see happening. 
As for testing to a stall, I don't see why anyone would really need that info, 200 rpm is low enough and that's more for testing the controller settings. Only motor guys care about that stall torque number for equipment start ups. If the motor is stalled it means your not going anywhere, 0 hp, what fun is that.


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## 2cycle (Jul 2, 2009)

Well I've aquired a water brake dyno that can test up to 300 hp @ over 10,000 rpm, so over driving the dyno input should keep torque within range. I still have a few more items to gather up before building the test stand. I will have the whole thing built for less than $10K and it can be used for our small and mid sized 2 cycle race engines as well. 
Once I get it finished I will need some test motors which I can get down the road at the forklift sales and service shop.


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## Dalardan (Jul 4, 2008)

Good job, 2cycle. Keep us feeded with pics of how you install your setup, I'm curious.

I've also just bought a water brake rated for 300hp (Land and Sea 9" water brake) for our Formula SAE team. Which brand is your's?

We'll begin the construction of the bench unit in a week or two so, if you're interested, I will show pics of the installation. Do you plan a mobile unit or a fixed one?

Dalardan


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## 2cycle (Jul 2, 2009)

Dalardan said:


> Good job, 2cycle. Keep us feeded with pics of how you install your setup, I'm curious.
> 
> I've also just bought a water brake rated for 300hp (Land and Sea 9" water brake) for our Formula SAE team. Which brand is your's?
> 
> ...


Same brake, Land and Sea. It's not new but it's not very old either. We plan to do a fixed unit in the shop. The test stand itself will weigh close to 600 lbs because it will have an inertia wheel built into the bottom half of it for testing through the CVT transmissions and chain drive. Tuning the CVT is the toughest part of snowmobile testing and at least getting started in the shop before taking it to the race track is a huge help.
When it's built I'll snap some photos. I would like to see your set up as well.


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## Dalardan (Jul 4, 2008)

Dyno is in mail, should receive it this week. I've got my motor guy drawing the bench at this time, should by able to post the drawings this evening or tomorow.

Dalardan


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## Dennis (Feb 25, 2008)

If you need a power source for the DC motors then just simply use an industrial DC speed drive, that way you avoid needing batteries. What will be your final decision though is cost. An industrial DC drive of for 300 CONTINUOUS HP will be $15,000 to $20,000 range where as the EV controllers will be cheaper, although not continuous rated to deliver that much power.

Also any industrial motor manufacture that is a member of NEMA cannot fudge HP figures or they get into hot water with NEMA and they will be put out of business.

EV motor manufacturers though are not NEMA members it seems so they probably do some HP fudging I suppose, but so do car companies. A 400 HP corvette cannot deliver 400 HP for too long without the engine throwing out its internals, but it does not have too since it is only being asked to do this for acceleration.

Now if the EV motor manufacturers gave a duty cycle versus HP rating then we have some very valuable information that will help us know how long the motor can provide various HP figures for acceleration without smoking off the varnish.

So with this said, why not have thermal couples you can place at various points in inside the motor? Then have some various programmed loads that the dyno can put on the motor. Have the motor run till the temperature of the windings get to 180 C if class H rated. This should be tested in a temperature controlled environment of known temperature so that the temp rise data is accurate. You would then note the time it took at X load of the motor for the windings to get to 180C and graph this information as time motor can take X load until temperature limit is reached. Then repeat the procedures for other load points. This information will be very valuable to the EV community!


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## WSJ (Sep 18, 2008)

My Dyno measures motor torque, voltage, current and RPM. The load consists of two 400 A aircraft generators, which pivot on bearings to apply force to a load cell. The generator field voltage is adjusted to very the load. A remote pot is connected my EV controller and the EV battery pack powers the motor under test. Two centrifugal blowers are used to move cooling air through the generators.


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## 2cycle (Jul 2, 2009)

nice set up. I have been bombarded with work recently so my project is at a standstill. I have changed my direction on style of brake to a water brake with a seperate load cell not like the Land and Sea integrated strain gauge. I was just about to pull the trigger on the Land and Sea when I got too busy to deal with it at the moment.


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