[2cycle]

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.

[AmpEater]

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.

[2cycle]

Originally Posted by AmpEater

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.

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.

[Dalardan]

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.

[2cycle]

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.

[Tesseract]

Originally Posted by 2cycle

....
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.

[2cycle]

Originally Posted by Tesseract

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.

[Bowser330]

Originally Posted by tesseract

....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!

[2cycle]

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.

[Tesseract]

Originally Posted by 2cycle

...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.

Originally Posted by 2cycle

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.

Originally Posted by 2cycle

...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.

Originally Posted by 2cycle

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...