joeqsmith49

https://www.youtube.com/watch?v=X5uIXf0YuaU https://www.youtube.com/watch?v=E2lkUI1Vtl0 I ran into a snag with Google and lost my videos. Uploaded the two videos I had saved of my toy dyno. Here is the last larger home made one. Not doing closed loop controls with it yet but getting some real good numbers off it.

Brushes were fine. Looks about 0.025" dia wire and 26 turns. Had some 0.030 and was able to get 13 turns on it. Made a couple of pulls with it and the new winding really changed the performance. Motor will now make 45 Watts at 10,000 RPM. At 20,000 RPM it will make 62 Watts. Not an electric motor guru but seems less turns pushed the power range up and lost torque. Sounds pretty poor at 25,000 RPM with the out of balance and bushings going on it.

Appears one winding may have been weak after heating and broke. Showing the brake. There are cracks in the copper.

Who makes a good motor? Something with ball bearings and 100 - 200 Watts continious output power. I can use up to 1.9" diameter on the motor mount.

This next video shows me making one last pull with the Green Machine Pro. This motor has made several pulls and the it's brass plain bearings are starting to fail. You can hear it in the video. You can watch how the arm moves as the load is applied. The little 66 Watt motor is no match for my dyno as it ends it's life in a total meltdown. http://www.youtube.com/watch?v=ip2BtaHqnFw

This short video shows how to calibrate the dyno. Basically remove the linear pot and start putting the weights on. The software walks you through the procedure. You can use as many weights as you want. http://www.youtube.com/watch?v=Fm8MrdZ8cUQ

Showing the entire toy dyno with calibration standards and test motors.

Made some progess with the linear pot. I wrote some software for it and tried it out. It's about as good as you would expect for the price. I need to get a better test motor that can make about 100 Watts of continious power. The little Green Machine has been over heated a few times now.

I have a few different springs that I can use to set the torque range. The small VCR motor will be a good test to see how sensitive it is. My plan is to benchmark it against the balance. The new software can run the dyno in speed, torque and voltage control modes. There are seperate tuning parameters for each mode. There are various ways to display the data now as well as some simple post processing.

The assembled unit. It's not going to be near as good as the balance for accuracy but it does not cost much and can be read much faster. I plan to use the weights to do a 4 point curve fit. The spring should be fairly linear over the short range.

Custom clevis, base, spring, sensor and calibration weights.

Using high grade scale to make up some calibration weights for the new torque sensor.

Thanks. This is just a little home project. A few years back I helped a friend with a small water brake he was building. This was a 75KW or so, direct drive setup, mostly used for small car motor break in. Places I have worked at have always used direct drive systems. Mainly these have been eddy current types and most could do some basic controls. Some were motoring type. These were rated for much higher power levels. I have been thinking about building my own large dyno for some time. I would like to do more with the model dyno but I don't like risking the balance. My plan is to replace it with an LVDT or linear pot. Below is my very low cost torque sensor. Linear pot with a spring. 100 grams is about half travel. So 200 grams on a 6" arm. Absorber won't handle that sort of power. I have not had time to try it out yet.

Added small compartment to hold a few tools at the ground shaft used to align the unit.

A second video showing the response time while modulating the absorbers output power. http://www.youtube.com/watch?v=muZUoeE88jw&feature=related