SINGLE flywheel help!

The speed of my team’s flywheel is inconsistent. It runs perfectly for like 10 minutes of testing, then slows down and eventually won’t spin up. I am putting the 2 V5 motors at 87 rpm, 1:25 gear ratio. (we also have a heat sink on one of the motors)
UPDATE: It now overheats about level one after about 30 seconds of running.

Make sure you check all joints for friction. Also remember, that each match is only 2 minutes and you will never need to spin your flywheel for 10 minutes.

It only spins for ~30 seconds before overheating above level 1

Can you post a picture? This sounds like a friction problem.

Again, like everyone else has said, it is friction. Our B team was able to run a 1 motor 200rpm 1:35 double flywheel without many issues.


How could I decrease the friction? (picture shown below)

You should first check every axle and see if it requires basically no force to turn it. Everything should be super smooth and liquid. If it isn’t smooth, you need to check your bearing blocks and make sure the gear box is square (everything is straight with everything else). You also want to make sure that your axles are perfectly straight. Even a slightly bent axle can cause serious problems.

Next, make sure that the axle with your flywheel on it is short. If the exposed part is too long, it may be bending at that high speed and will cause problems.

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I would also make sure that the structure is square - if the support is non-parallel in any dimensions, it will cause the shafts to rub against bearing flats/blocks more…

Also, only one of the motors is overheating (the bottom one). Should I replace the motor or replace the bearing blocks?

You’ll want to check the bearing block first. If spinning an axle inside of it is smooth already, the motor may be bad. But if the bearing block is rough, you could either drill it (this is the better option, we drill all of our bearing blocks), or replace it.

Looks like you notched the c-channels to connect the vertical structure - is it lined up with the holes correctly?

A good test is to put the V5 motor on coast and then try to spin the flywheel manually. If there is little friction, the flywheel should spin for 20-30 seconds depending on weight. If it only spins for for 5-10 seconds before stopping, it is definitely a friction problem.

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it spins for about 4 seconds

friction problem then. take out the shafts and make sure they’re all nice and straight, try drilling out the bearing holes and the metal holes the shafts go through just a tad larger to reduce contact, make sure the structure is all 90 degree angles or else shafts will be pressing against bearings, adding grease helps, I like to sand down my shafts a bit to smooth them out, make sure no shaft collars are directly contacting metal, make sure the gears aren’t being pressed into the metal and nothing is being forced into places they don’t entirely fit.

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I see that your flywheel shaft is going through 4 bearings. This is not a good thing, since it is nearly impossible to line up more than two bearings perfectly. Any more than two and you are likely to get massive amounts of friction on the single most important axle of the system. Take off the bearings on the ends so that the gears on the ends of the flywheel axle are cantilevered.

Also, what is the internal gearing of the V5 motors? 100RPM or 200RPM (Red or Green)? If the former, your ratio is indeed 25:1, but if the latter, it is more like 50:1, leading to a flywheel velocity of 5000RPM, which is completely unnecessary.

Make sure that your spacers aren’t too big for the space. You should be able to freely rotate them on the axle independently. If they are too big they are pushing against the gear and prohibiting the motors from turning the flywheel.

You said the motors were at 87 rpm. Might I reccomend you put them at their max power? That might help.

The motors are the green ones. (200 rpm)


Also, I noticed that one of the c channels is completely bent. Could that be the problem?