356 Engine Dynometer

[Jbrooks]

Still awaiting parts, but I have been looking a commercial units and their specifications. Doing some math

I am building this based on a Telma retarder used on a F450 or MB Sprinter application. This Telma unit uses 6 coils in three stages , their coils are turned on in pairs, Mine has 16 coils in 8 stages, but I can change that after I get it together. The math says I may have over built it as usual. The numbers look good. All you need to insure is that you pair up the coils 180 degrees across the rotor, and stage them next to each other so the fields and interact. The below curves are adjustable by adding or re-configuring the coil packs at full voltage. I should also be able to adjust the torque curves and changing the voltage to vary the current, changing the magnetic fields, changing the loads. .

After it done I should be able to program the retarder control unit for each type engine. Say for a 616/xx I should be able to dial in the load specifically for the engine configuration. I may not be able to do a 930 turbo but who cares, this is good enough for what I expect to see.

[Phil Planck]

Impressive John. Hope it works as planned.

[Jbrooks]

Phil
The house next door will be for sale this summer. Tom Olsen is a couple miles south of here, come on up.

Well slow day today waiting on parts so I started to layout the coil pack. Looks like 16 coils 22.5 degrees apart. The need to be arranged North - South, North - South and wired in pairs 180 degrees apart across the rotor. I am sure the wiring is going to drive me crazy. The will be turned on in pairs or maybe 4 at a time. Not only can I control the load with the voltage/current applied, I can turn individual pairs on or off. The theory works we will see how it works in practice. The loads should increase as you add coils, and if you and the next to each other they make more drag.

The math theory SEZ... ie; See photo Coils A&B and will produce stronger eddies currents and say A&C or A&E . Say coil pair A alone makes 10 pounds of load, A&B should creates 30 pounds since they can react together. , A&C might be 25 and A&E the normal 20. But ABC together should make 50-60, So sequencing the coils will produce predictable loads. Also the load increases with RPM. Higher the speed stronger the loading. I hope to be able to vary the voltage and the number and location of the activated coil packs and hold a stable torque load.


The coils are pretty small 2 x 3' with 5-600 turns each. Going to make a winder setup and do them on the old trusty southbend. Need to get each one as close as possible and wound tight.putting them in the center gives me twice the Magnetic flux per coil, since there is a rotor on both poles. I will make the center of cast iron rod put a focus pad on the ends ( looks like a small brake pad). they need to have about 1 mm clearance on the rotor. Getting that all aligned will be fun. also getting it solid and fixed will be a challenge. also balancing the rotor assembly and shaft will be interesting.

Enough for today

Thanks for following

[Phil Planck]

Wish you were my next door neighbor

[Jbrooks]

Ok guys, measurements are done, ordered some parts today. The main shaft is 0.875 diameter and a little over 2 feet long. I ordered 5 pillow blocks and the load cell. I have some 3/8" plate in the pile so it looks like the bottom will be supported by a plate, I will weld up a L bracket that the bell housing is bolted to with a bulkhead bearing block attached to the plate. That will carry the load at the flywheel end. I will make the shaft tapered and splined and extend into the gland nut bearing. Then there will be at least another bearing block on each side of the rotating iron mass. The center-line of the crank will allow about 3-1/2" bottom clearance on the disc rotors.

That clearance is good and will allow me to bring the wiring in to the coil pack from the bottom. I will mount the coil pack on the left side with two pivot points and a 6 -12" arm on the right side center of the coil, that will tie into the top of the load cell. This arm will put the load cell into compression and allow me to measure the rotational drag as a torque value.



My goal was to be into this DYNO for a couple hundred bucks, I am into this for a total of $227.85 so far. I have bought the bell housing, 7/8" drill rod for the main shaft, 5 bearings, 200Kg S type load cell. I have the steel in the pile so I think all the big out of pocket expense is done. The goal on this is to use to to break in new engines with 20-50 ft-lb of load and to vary the loading like climbing a hill when the engine is new. It will also allow me to do Hp and torque curves, but that will come after I get it built. The drag from the Eddie Current Adsorber is variable by both voltage and current. I believe this will have eight (8 coils, I will do some experimenting with them turned on in pairs and different sequences to figure out the loads.

Thanks for looking we progress
,

[JTR70]

Love the inventiveness of all of this. Looking forward to seeing how all of it all comes together.

[Jbrooks]

Being sequestered sucks, and salvage yards are not essential functions here. So I have not found a telma retarder for a sprinter for F450 here in the states.

So I have started building the dyno from scrap stuff in the shop. From the basic drawing below, here is a photo of the stack up. The bell housing will be attached to a tubing frame, holding a main shaft via a couple pillow blocks. The coil package will be fixed to the frame so it can move just a little, held in place with an short arm to the S type load cell. These 14" brake rotors on the bottom will attached to the main shaft and spins via a flywheel adapter. This adapter is splines disc that bolts to the flywheel like the pressure plate. The main shaft will fit just like the trans.

I will mock it up on an engine case get some good measurements tomorrow. Get the clearance distance for the starter, center high with an engine, etc. Then I need to figure out how to balance the rotational mass, source some bearings. The disc brake rotors should be close but they are too large to spin up like a crank shaft.

Here is the Horizontal layout. It look like the starter is the driver on length, but still under 24 inches long. The concept is to mount these rotors to a shaft supported by a pair of bearing blocks on the center shaft. Then fix the coils in the center of the disc, mount them on three points. Two on the left side and allow the engine rotation to pull the coils into the third point, the load cell to measure the torque. So far its measures out and will be very compact and probably not all that Heavy. .




I may go look for different rotors with a smaller center and larger disc surface but this is what I have on hand.





The rusty part shown is the rotating mass, steel brake rotor with a fixed coil pack in the center,. On top is the 616/901 engine adapter. . It progresses, thanks for looking

[Jbrooks]

Found a commercial device called a " Telma Retarder" used on trucks and buses for electric brakes, It goes into the drive shaft to slow the truck. I was looking at building one from some 14" disc rotors and winding my own coils, turns out the junk yards have these for the copper scrap weight. Yahoo ........ They are pretty simple, the discs spins and the coil is fixed. The magnetic field is induced into the rotors and created the drag. The magnetic field is controlled by the current through the coils, the faster the disc spins the more drag. So at higher RPM it actually needs less current.


The smaller ones for sprinters or small trucks will almost bolt up to the VW T-2 bus bell housing. The sage continues, off to scrounge through the truck junk yards.

thanks for looking.

[Jbrooks]

Phil

Thanks for the video, that is what I am looking at. I am trying to design the load about the diameter of the flywheel, Or something I can attach like the pressure plate to the flywheel and keep it inside the bell housing volume. I had pretty good luck making a magnetic vise, i believe 6-8 of them may create enough drag to eat 205 Hp. Still doing the math, but hope to have it done in a couple months since I have to stay home anyway,

the drag theory https://upload.wikimedia.org/wikiped...bers_Work.webm

The one here is a 800Hp Mine will be similar just scaled down.
https://www.youtube.com/watch?v=pwPP...M#action=share

[Phil Planck]

John

I know a guy who raced formula V years ago but cant find his phone # using internet. He is on linkedin but have to join to contact. Let me know if you want his name. He built a dyno for the vw engines.

Also, this youtube may help:

https://youtu.be/ncjaVhwhKFg

[Jbrooks]

i am thinking about a small engine dyno to run 356/911 engines. Anyone out there that has one or done any research into making one. I am looking at using an Electric Eddie Current load or electric brake. Should probably be about the same size as my 616/40 test stand, or maybe a replacement for it

looking for anyone that has a engine dyno or any ideas on the construction or design.

Planning on a VW T-2 bus trans bell housing , bolting an adapter to the flywheel into the Eddie current load. Your thoughts please