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Setting up HUB dyno

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(@edgars)
Posts: 28
Member
Topic starter
 

Hi!

I am setting up my HUB dyno with 2 Telma 1600nm retarders. Using 2 Semikron skpc200 controller. Anybody can look at my settings and tell if all is fine? I got problem that brakes are not working when trying to measure power and car behaves strange. It is 2011 BMW 3.0D with open diff. Tried to measure car with welded diff (100%) and all was fine, brake were working, power output was realistic. Here is video with BMW test: https://photos.app.goo.gl/cqxGT21DpxfFakux7

Car is trying to brake one wheel because it sees difference, even with switch off DSC. 

 Attached screenshot from brake setup. 

 
Posted : 15/04/2019 8:05 pm
(@edgars)
Posts: 28
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Topic starter
 

Here is picture from my power sweep setup.

 
Posted : 15/04/2019 8:06 pm
(@edgars)
Posts: 28
Member
Topic starter
 

When calibrating rpm and finding gear ratio there is button: force both brakes to keep same rpm. But nothing happens. When I manually test brakes I can hear that they are working and I fell that it starts to brake. 

 
Posted : 15/04/2019 8:21 pm
(@admin)
Posts: 1457
Member Admin
 

Hi, I see from the video that both brakes are off during the whole run. You are easing on the throttle, and the RPM rises slower than the ramp you defined, so the brakes remain off. 

Also I see you control the Semikron using a PWM, but they need an analog signal. Set it to use an analog signal from 0V to 5V, and swap the jumpers inside the box. Using a PWM does probably sort of work since the switching frequency is so high, but analog is the way to go. You also defined 10% minimum PWM, which would mean the brakes are always on a bit. So in the video, even if the gauges showed 0%, the brakes were on somewhat, which is not a good setup. 

 
Posted : 16/04/2019 12:37 am
(@edgars)
Posts: 28
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Topic starter
 

Thats why 0-5V option wasn't working for me. I thought that this jumper is needed only on older version like v3. Found somewhere here on forum, but misunderstood something then. Thanks! Will test it soon. 

 
Posted : 16/04/2019 9:23 am
(@walter)
Posts: 245
Member
 

Hi Edgar, regarding your pm, you can see my setup here:

https://yourdyno.com/community/questions-and-answers-questions-and-answers/pid-settings-post-retarder-type-and-settings/

After to see your video, DSC is still active. had similar problem with one BMW 325 E46. in my case, brake light was yellow and was impossible to test it, until i dissable 100% and brake light was red. 

 
Posted : 16/04/2019 9:52 am
(@edgars)
Posts: 28
Member
Topic starter
 

Thanks, Walter. You better mention in that post that you are using hubs. 🙂 Will test this on my setup today. 

 
Posted : 16/04/2019 10:10 am
(@edgars)
Posts: 28
Member
Topic starter
 

Changed jumper, tested manually with slider 0V-5V. Brake is working, but still when I slide slider to 0V brake is still active and braking a little bit. When I switch off AC and plug it back brake is off. Again touch slider and brake don't come loose. What could be problem now? I am using yourdyno OutB and 0V. Measured with multimeter and it works correct 0 - 5V like in software with "slider". 

 
Posted : 16/04/2019 1:57 pm
(@walter)
Posts: 245
Member
 

Maybe problem is with your current suppliers? anyway remember when Eddy brake is zero rpm if it's at 100% it wont block it. check your brake map of your Eddy brake. more rpm, more torque.

how do you have wire up Eddy brakes? any phots or your setup?

 
Posted : 16/04/2019 2:51 pm
(@edgars)
Posts: 28
Member
Topic starter
 

Like in this picture:

https://photos.app.goo.gl/ahS7fvTWLGstV1x26 - here is picture from actual wiring.

 
Posted : 16/04/2019 3:06 pm
(@edgars)
Posts: 28
Member
Topic starter
 

Using these thyristors: https://www.tme.eu/en/details/skbh28_06/single-phase-diode-thyristor-br-rectif/semikron/skbh-28-06/

 
Posted : 16/04/2019 3:15 pm
(@walter)
Posts: 245
Member
 

Ok, i dont know much really using that power suppliers, i think the best way to test it is with some rpms.. if i understand what you means, problems is about your power suppliers, like it keep still current when brake is off. normally thats a big problema using Eddy brakes, i dont remember right now how it's called, hysteresis? so sometimes it's needed something that when you get off brakes, there is a consumption current that definitely brake is off of current, otherwise when you get off brake, brake Will keep a bit of current for some short time. 

 
Posted : 16/04/2019 3:16 pm
(@edgars)
Posts: 28
Member
Topic starter
 

But in my case it isn't short time. They were standing maybe 10-15min and then I switched off AC.

 
Posted : 16/04/2019 3:31 pm
(@walter)
Posts: 245
Member
 

measure output from your power supplier to your brakes when yourdyno is 0v. even try to disconnect yourdyno then measure output from your power supplier you brakes.

 
Posted : 16/04/2019 3:55 pm
(@edgars)
Posts: 28
Member
Topic starter
 

That gave me some information. Measured 5V output from yourdyno - Retarder - 192V. 

If I move slider faster to 0V, then at retarder still stays 60V. I can plug off yourdyno, still 60V. Only when I plug of AC power source, then it goves to 0V.

If I move it slowly percent by percent at the end, then I can get retarder to 0V. I can move slider fast till 0,5V output and then I need to move it slowly. If I configure 0% - 0,45V and 100% - 5V, then I can move it fast how much time I ever wanted. Output to retarder goes from 1-3V to 192V and back. but still it has always aplied 1-3V on one side, other retarder even ~10V. 

I made video for better explanation: https://photos.app.goo.gl/CFv38DCNsQCvwLZM6

not so good quality. If needed, I can upload on youtube HD quality.

 
Posted : 16/04/2019 4:42 pm
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