Q&A Forum
Greetings tuners!
I have a portable eddy current dyno mounted on a trailer. Setup is: Frenelsa 4500Nm retarder, SKPC 440, SKCH 40, with Yourdyno and a expensive 5m USB cable.This setup has run for several years now, But a issue keeps comming up.
When running a dyno measurement i often has connection issue. Connection between yourdyno and laptop comes and goes several times within seconds under a dynorun. This result in engine stall as retarder brakes 100% for a small period when reconnecting yourdyno to laptop. This problem has been worse than now. But it seems impossible to completely remove. I believe its some kind of electrical noise. What i has done so far to keep this issue away is:
Grounding everything on dynotrailer
Put filter+SKPC+SKCH in steelbox and gounded
Moved yourdyno controller as far away from powersupply as possible (aprox 1,5m)
Mounted yourdyno in grounded steelbox.
Replaced all cables to shielded cables and connected only 1 end to ground
Tried several USB cables. its not possible with shorter cable than 5m. (does there exist wireless connection to yourdyno, or better solutions?)
All this has helped on the issue. But i still have connection dropouts often. What i noticed is that when brakeload increase or decrease very fast it seems more often to have connection issues. So when using rpm sweep dyno regulated fast from 0 to 40% as this is the point where brakeforce from retarder is starting. Often connection dropouts is happening here because of fast regulation. If i use brakesweep and apply 40% startbrakeload and sweeps at maybe 10rpm/s then change in brakeload is slow and i often dont have connection dropouts.
Does any of you have ANY idea on how to remove this problem? i am open to all kinds of solutions and tests to get this dyno connection more stable.
Cheers
Hi there,
On the grounding you are using, make sure not to create any loops. You can try this sequence:
Ground coming from grid -> Electric box -> YourDyno box -> Power supply -> Retarder -> Chassis. You can also try disconnecting from grid ground and connect directly to a physical ground stake.
You can also try to add ferrite beads over high current/noisy cables.
Another thing is the filter before and the power supply.
Here is a line filter you can try: https://www.elfadistrelec.no/en/mains-filter-30-250-vac-schaffner-fn2020-30-08/p/16963452?origPos=233&q=%2A&pos=1&no-cache=true&origPageSize=10&track=true
On the SCR gates you should have snubber filters.
Hello
You have a big retarder with a lot of inductive current.
SKCH have built-in flyback diode but perhaps dead....
You can try an external flyback diode. A big one, over 100 Amp fitted on a little heatsink.
Best regards
Thank you for feedback. I will try to add ferite beads on the wiring.
The filter i have mounted is this type: https://dk.rs-online.com/web/p/emi-filtre-og-tilbehor/7821009/ . Would the other be a better choise?
Adhoc-racing: i will try to investigate this.
Thank you for answers! - I will report back after testing.
I have tried munting(A LOT) of ferite beads on all wires on dyno. I have tested aprox 15 tractors since. This have not helped in any way. i still have connection issues when retarder is changing load quickly.
adhoc-racing - do you have any link for a flyback diode that could work?
If anyone has a solution or knowledge to get this working without connection issue then dont hestitate to contact me on mwp1985@gmail.com . I will pay for guidance or solution!
Cheers
Another issue, that might be relative to the other, is that when brake sweep run is done (and youdyno says done/end) then brake will keep being loaded up to 10 seconds after end of run. has this something in common with power supply issue?i need to turn off "power take out" on tractor so engine will not stall.
@madswp, do you do very long runs or have a very slow computer? After a run is complete, the run is stored, filtering is applied, engine power calculated, etc, which typically take a second or so (connection indication will go red briefly). I think the brake is turned off after this happens (yes, an improvement point!).
Is the connection indication going red during these 10 seconds?
If your PC is slow then the connection may also come and go a bit, since it will be struggling to keep up with the data.