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Cute Wee Gem's Dyno build


cute wee gem

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2 hours ago, cute wee gem said:

I uploaded a video of my cat who loves to hang out with me in the shed, even when I'm making loads of noise. The video also shows my redneck contraption in action

Tortron, I think about 100kg of steel wool was made lolIMG_7754.thumb.JPG.a028f6879cb7d4367973c0a934c51e1c.JPG

That is farking epic! Great work.

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  • 2 weeks later...

@cute wee gem - this is wild. I'm super impressed at how deep you've delved into the project. 

Will you need to calculate the inertia of the roller so it can be factored into the power readings? If so, any idea how you'll do it? 

I've been following this dude's stuff for a few years now. He has an inertia-only dyno made from an old electric motor that gets used for motorbikes. It doesn't have any sort of retarder. He was lucky that the motor manufacturer had the rotor inertia specs available for him to base his figures off. He's also created some DIY dyno software called Ardyno that's available fairly cheaply (you have to get your own chips printed, but that's not the end of the world). 

 

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Cheers Markku, yes I will need to calculate the moment of inertia of all of the rotating assembly. The YourDyno site has some very good design stuff for both brake and inertia dynos, which include calculators for MOI - however this isn't always 100% accurate.

The best thing about an eddy current dyno is you can easily figure out the moment of inertia by doing a run up to X rpm and then back down again with the engine at full load (retarder overpowering the engine to bring it back down), which will give you a graph displaying the difference in HP it takes to accelerate and decelerate the roll/rotating assembly.

This video explains the process (maybe skip to 1:45)

2 stroke stuffing is excellent btw! Love his videos

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Cheers dude.

There's not a huge amount of force on the load cell in relation to the hardware capacity, keep in mind it's 450mm from the center so it has a huge torque advantage.

But better safe than sorry, so I've planned to add a stop to the opposite side of the retarder as it will be spun backwards for FWD applications, and for RWD if anything were to break, the bracket will actually hit the lower mount/frame.

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On 23/12/2020 at 09:36, cute wee gem said:

While I waited a few weeks for the concrete, I built a frame for the dyno.

 

Speed sensor bracket

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Load cell bracket. This is what measures the torque.

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Electric drum brake to lock the roller when mounting a car.

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Frame painted. The part sitting next to it bolts into the top to support the floor coverings (steel checker plate)

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Epic build man! I'm picking there will be no sideways load on the roller? Ya just running a standard p series housing i see.

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Cheers man, yup just standard bearings. From the photo's I've seen of other dyno this seems to be fairly common? Unless I'm missing something critical, feel free to chime in.

I would assume there would be bugger all axial load? Once again I'm no engineer so if there's anything I've overlooked feel free to set me straight. I'd much rather change some stuff than have it fly to bits!

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