1972 Continuously Variable Transmission For Use In Wind Turbines (CVT)

foreign so there was a time when transmission meant very little more than a bar if you think about it the horse is the engine and it goes here where its presses come from this to the horse this linkage can be seen as the transmission which transmits the horsepower to move the carriage this would be another example it's obviously a fire truck and you've got 13 men each with half a horsepower pulling on these wooden bars that connects through here to the axle working the pumps you can see this as the engine this is a transmission because animal and human power were the predominant forms of power for a very long time and simple Transmissions like that well they were more than adequate there were direct power transmission but then of course this thing came along as a very early example and so if we look at the steam engine which the cylinders right here there's the rod there's the linkage to the wheel it's still an extremely simple transmission basically a linkage transmission nothing wrong with linkages as a transmission when there's a match between the speed and the amount of effort you want to put into something like with the firemen pumping up the pump engine the horse as long as you don't want to do 100 miles an hour and a steam engine that's just Towing 40 tonnes of coal or so the problem arises when the mismatch arises and that's more likely when you're doing heavy loads or your engines improve Improvement means a decrease in size and increase in power and increase in speed and then these things come along creating a whole host of problems with transmission that is getting the power from the engine to where you use it and that's the wheels where they meet the road and of course in a car there's a huge variety of conditions that a car has to cope with and just about the only solution his gears gears are a solution to a problem but just like every solution it brings its own set of new problems with it there's a surprising loss of power when it comes to changing gears a lot of the energy of the motor is lost of course the answer to that is a variable transmission where you don't have to change gears gearboxes change gear ratios by stepping through a set of gears and that's whether it's manual or an automatic gearbox a variable transmission provides gear ratios and a constant without actually changing and that allows the engine to run at a constant RPM its most efficient RPM while the road speed of the tire varies now you might think something like a variable transmission was pretty modern but the first variable transmission was 1879 by Milton Reeves and he used it in Sawmills in 1911 the Zenith Granada motorcycle was pulley based a year later the Raj Whitworth multi-gear was released and that was put into cars as early as 1913 right through to 1923 small three-wheeled cycle cars built in Spain in the 1920s were also using it in the 1923 the clino built in the UK 1926 the Constantine Esco Saloon also built in the UK used variable transmission now this split into different types and perhaps the most popular type is the friction type of which the most popular of them is the pulley version the pulley version is essentially two conical pulleys satisfa side by side and as you push and pull those tonical pulleys in they change their effective diameter two sets of those with a V belt in between them can create a variable transmission as the v-belt goes up and down between the two pulleys the pulley's being pushed in and out at the same time these can be belt driven or Trend driven and they are about 88 percent efficient Which is less than a manual gear but they do make up for that lack of efficiency in that the motor is running at its Optimum RPM all of the time because of that there's again of efficiency there perhaps the next most popular would be the con type the simplest contact is one cone with this pulley wheel that slides up and down the cone of course as the diameter changes then so does the Gear relationship between the two perhaps the most well known of those is the Evans variable speed countershaft which produced in the 1920s the simplest form of friction drive is quite possibly the friction disc can you see examples of this in things like lawn mowers it's just a disc that rotates instead of a cone and a pulley wheel Moves In and Out of the center of the disc again changing that speed relationship a more modern development is quite possibly the toroidal static variable transmission and this was used on the Nissan Cedric it is essentially two two cones a curve with the points of the currents hitting each other and a couple of discs that are able to move in and out of those columns set inside a toroid and that movement of the discs against the cone shapes creates the variable transmission one of the toroidal cones is obviously the input and the other one is the output and advantage of a toroidal cone is that it can transfer for higher talk loads and in some designs can move in Reverse another type is the hydrostatic or hydraulic type it essentially uses a variable displacement pump and hydraulic motor so the transmission converts hydraulic pressure to the rotation of the output shaft quite possibly my favorite is the ratcheting type it uses a system of levers to transfer the motion from one point to another and then a set of ratchets that can only forward Direction now there's some people who said that this isn't a true variable transmission and perhaps in construction it's not but in its output it certainly is principle dates back to the 1930s there was a patent in 1994 using the ratcheting system in a scotch yoke mechanism another really great type more modern is the epicycle or planetary gear type where the gear ratio is shifted by the tilting axis of spherical rollers to provide different contact radiuses which in turn Drive input and output disks is similar actually to the toroidal CVT and the final one I want to mention is the magnetic variable transmission this is really quite exciting and very much in development at the moment with a couple of companies claiming that they've developed them but enough products on the market and yet the idea is instead of using frictional geared coupling using magnetic coupling to achieve a constant variable transmission Okay so it's fascinating stuff but of course why be fascinated with it well cvts not only can take a constant input from a motor and apply it for variable conditions the reverse is also true if conditions vary it can change that into constant output and of course that's exactly what you want for a wind turbine because then a wind turban the wind is basically all over the place but what you want is a constant RPM out so you get a reliable production from your generator attached to the wind turbine and they're a huge source of research into wind turbines and how to improve the output of wind turbines so if you want to improve the output of your wind turbine a variable transmission is something you really should be looking at and of course if you're getting over speed it'll help prevent over speed as well so it's got a good safety idea about that as well no I'm fascinated by generation and wind turbines as you know so of course I'm interested in variable transmissions and it's only give it a go and what I've chosen is the Evans model it's two conical rollers and of course I've done a tinkercad file and the tinkercad file link is in the description if you want it it's pretty simple to print off those two conical rollers and I've stuck some long bolts through it and some bearings in their taxes and the axle and the bearings of the axle now I printed this in pla which is a bit too smooth so I've coated the outside with a bit of sheet rubber this I got from one of those exercise bands and I just glued it onto there now traditionally what you use is a roller like this and the roller have you seen goes in between the turn handle the roller changes its position as the roller changes position then the output changes but that roller moving it is a bit of a drag no pun intended because of course it won't want to go that way so I was thinking of a simple improvement with the end of this it's a golf ball and then tinkercad you'll find this clip it's in the same file the clip is so the golf ball can go in it now that golf ball can rotate in that direction but it can freely rotate in that direction as well so we pop the golf ball on and we give that handle a turn we'll get one speed here there we go and if we move the golf ball up we'll get a much slower speed despite me turning the handle at the same rate which of course is what a CVT does so the golf ball Improvement allows me to move that while these are rotating so that we can get a constant variation in the speed of the input and the output by the movement of the golf ball now the next thing to think about is how to automatically move that golf ball depending on wind conditions but had a look at it shared it with you improved it and it's all in the video so I hope you enjoyed the video hope it does inspire you to have a look at variable Transmissions because they are frightfully interesting things for wind turbines thank you very much for watching please do remember to like And subscribe

Channel: Robert Murray-Smith

Views: 191,820

Keywords: constant, variable, transmission, wind, turbine, robert, fwg, tnt

Id: Yqer2Nazm64

Length: 10min 0sec (600 seconds)

Published: Thu Jun 29 2023