356 Engine Dynometer

[Jbrooks]

John

Not too much science, just some magnetism and a couple physics laws. The magnetic field just tries to stop the disc rotation.

Fixed the wobble, larger hinge pin with a shim between the hinges. Welder works super for a power supply although it starts at about 20 amps on the lowest setting. But so far its working, when I spin the disc up to about 2000 rpm with an electric motor, it takes about 2 minutes for the disc to slow to a stop. Spin them back up, turn on the welder stops in 10-15 seconds. still trying to get the instruments to read properly but it seems to be working as planned. Have not had much time to work on it in the past couple weeks but its is progressing .

[Jbrooks]

DYNO UPATE

My shop made Engine Dyno works but it was not operating up to my original calculations. after a couple years of messing with power supplies, input current flows etc I almost gave up. I can live with it for setting new engine rings settings carbs and some tuning. It works OK.

Last week I was talking to a friend who is restoring an 912. I talked him into electroplating and cad coating his hardware and shiny parts himself at home. They were splendid and while talking to him he explained how he had calculated the surface area for the timing and current flow. the zinc is a little tricky to get it to shine right out of the bath. He took a photo of the part lying next to a graduated scale. the using an Ai APP, he sent the photo to the Ai and ask it for the surface area . The Ai would come back with the answer including the tread faces and the calculate the exact number of Milli-amps setting for each component. I had never use and Ai so I was completely amazed. even the brake calipers looked new.

So last week I decided to ask Ai about my Dyno , I was amazed again by this new technology. I described the device to the chat bot. Coil size number of wraps the disc size, hexagon locations etc. The Ai kept asking logical questions an after about an hour. after 10-15 questions it came back an told me I was making an eddy current brake. It started doing the math sending me the formulas an asking for data on voltages current flows. power and disc thermal heating. I ask it to plot the data an it did the charts. It computed this as a solid disc, and recommended ventilated disc. When I loaded that they were ventilated it completely recalculated the entire device. It was very interesting the comments were intelligent and to the point. The math was correct

I sent the Ai chat bot two photos, one of the electromagnet locations and another of the entire unit with a 616/ case installed. The Ai then identified the hinge on the hexagon and the load cell and the Ai identified it as a Porsche engine Dyno, ( probably found this web site). Then it came back with some specific on the build, it saw some hand written resistance so a couple coils an identified the mounting material as a galvanized steel sheet metal. Ask a couple questions on the resistance marking an verify the steel mounting brackets.

Then to my amazement the Ai calculated the magnetic field induced drag as torque at the load cell and was very close to the 60 foot pounds, I was seeing. Then the Ai explained that my mounts were steel and not focusing the magnetic field into the rotating disc in the optimum locations, losing efficiency. It suggested plastic or stainless steel mounts. I ask it for a design and it can back with a trapezoid mount. I ask for a drawing and it came back with a pizza shaped wedge with a 1mm space between the mounts electrically isolated from the hexagon mount. It suggested using .090 stainless for the brackets instead of the .063 I was using. Then I ask it to recalculate the drag coefficient with this update installed, A SIXTY SEVEN PERCENT IMPROVEMENT! A 67% improvement and at a lower voltage with less current flow and less rotating disc heating.

Now I know why everyone is raving about using Ai chat bots, I was using a Google search Ai ,mode. Its very good from what I can see. The ability to analyze a complicated device by asking you questions and looking at a couple photos is flat amazing. you should give it a try

I will do these suggested updates to the mounting coils and keep you up dated on the outcome.