My channel is about building homemade alternate energy equipment, electric cars, CNC machines, machine shop work, solar energy, metal casting, wood gas, generators, glass blowing, electronics, preparedness, and whatever I'm working on at the moment.
The load motor is being driven mechanically by the engine or motor under test. In video, the motor on the left is standing in for the engine that will be tested in the future, and the brake motor on the right is trying to keep it from turning by acting as a brake. By measuring the braking torque and the RPM, we can easily calculate the horsepower. If you want to go deeper into the relationship between Torque, RPM, and Horsepower, take a look at my Torque/Horsepower video. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-MpVTCJ0NyMw.htmlsi=C9wsSTQ7W3hAA-I4
I think you misunderstood my question. I meant what are you driving the motor on the right side with electrically? Are you backdriving it with a vfd or simply adding dc stator current to provide braking? What is connected to the load motor terminals. Sorry if I was unclear. Mark
@@markmarkell9209 Oh no worries! I realized "driving the load motor" could be interpreted in a couple different ways, I just picked the wrong one. Anyway, I'm simply feeding DC to the stator of the load motor and varying the voltage/current with the variac. The variac feeds AC to the rewound microwave oven transformer, then the lower voltage AC from the secondary of the microwave oven transformer is fed to a big bridge rectifier. The DC from the bridge rectifier is then fed to the stator windings on the load motor. It's all very cheap, simple, and low tech, and I happened to have all these parts lying about in my junk heap! Of course there are many different ways to accomplish the same goal, but this was the easiest path with what I had on hand.
Actually met Chris in Amarillo due to a failure of our Alternator on our truck. He bailed us out and we discovered that he is near genius. What an inspiring talented fella..
Keep in mind that the electromagnets in the brake motor do not care if they are running on AC or DC, but you must be able to control the amperage and keep it low enough to not damage the windings. That is where the Variac running through the bridge rectifier comes in. It allows me to control the DC amperage easily. Initially, I did not modify the brake motor at all, and it worked quite well in that configuration. After tinkering with it for a while I decided to remove the centrifugal switch on the start winding because it causes drag on the rotor until the rotor is spinning fast enough for the flyweight mechanism to retract away from the start winding switch. The mechanical drag was not a big deal since I was testing the swamp cooler motor at a high enough RPM that the flyweight was always retracted anyway, but my intention is to test my organic working fluid steam engine using this dyno at much lower RPMs. Cheers!
@@thetransformatorium7980Great to know, so since I only plan to test el.motors at regular RPMs then I shouldn't have to remove the centrifugal switch. And this also makes it easier to repurpose the brake motor to a regular motor again if one wants to.
Great construction. So is the 1 ft lever connected to the body of the brake motor, which is freely rotating? It would be good to see how the lever is mounted to the motor as well. And how do you make the brake motor, which is an AC motor, act as a brake off of DC? Thank you.
You are correct. The brake motor is mounted in ball bearings and is free to rotate. The 1 ft lever attached to the load cell of the kitchen scale is the only thing that keeps it from rotating and allows me to measure the torque. The beauty of using this technique is that the AC motor functions as a ready-made dyno brake just by feeding DC to the windings. The windings are not modified in any way. Powering the windings with DC sets up a stationary magnetic field that the rotor spins in. This sets up opposing magnetic fields in the rotor that try to prevent it from spinning, thus creating the braking effect. I hope that helps! Cheers!
This guy is amazing! I’ve contracted with him on numerous one off machining projects that I’m building. He’s never told me it can’t be done! His work is always top shelf!
Hello, I stumbled upon this account purely by accident. I was researching motors because I wanted to see how to take one apart and now I am deeply interested in your creations and learning from your creations. Thanks for making it. :)
Hi there, thanks for the kind words. I will be uploading a lot more content as I get projects done, and as I get better at making videos. If you want to take things apart, just go for it! I started off by taking anything and everything apart. Broken toys, old record players, broken lawn mowers, old wind-up clocks, you get the idea. There is little risk except for the occasional skinned knuckle. Just be aware that some stuff like refrigerators or air conditioners can be dangerous if they still have their refrigerant in them. What kind of motor are you wanting to take apart? Let the adventures begin! Cheers
I was not able to find OEM bearings for this motor, but since I had a lathe, I did not look really hard for them either! I would not have bothered with machining the end bells if OEM bearings were readily available though. Keep in mind, your motor could made by a different manufacturer, so bearings might be readily available. You really won't know until you take it apart and measure the shaft and bore diameters. Most newer cooler motors use ball bearings, and changing those is fairly easy and rarely necessary. This motor is made by A.O. Smith Corp which morphed into Century Corp. It uses what I suspect is a deliberately wacky size of a 3/4 inch O.D. with a metric 16 millimeter I.D. (.6299 inch) The bearings I used are 20 mm O.D. x 16mm I.D. 20mm is .787 inch, so I had to bore end bells from .750 inch to .787 inch. www.mcmaster.com/6658K33 Could this motor be fixed without a lathe? Absolutely! The approach would be different though. I would start with a very common 3/4 inch O.D. x 5/8 inch I.D. bearing like this one www.mcmaster.com/6391K247. Then Ream it to 16mm on the I.D. after pressing the bearings into the end bells. If you assemble the motor housing with the end bells while leaving out the rotor, you can use bearing you are Not reaming as a center guide for the bearing you Are reaming ensuring you get the reamer nearly perfectly straight, even by hand and without a lathe.
It actually took about 2 minutes to make fire using a broken automotive headlight, so I sped up the beginning to make it a short! I hope you all found it interesting. Cheers!
