V5 Motors Slowing Down After a Minute of Use

Hello,

I am making a tray bot this year and have searched everywhere for an explanation. During driver control, our robot runs fairly well and shows no problems. About a minute or so in though, it starts slowing down. My coach and I suspect that the motors are overheating. Could anybody tell me why this is happening or redirect me to a topic that talks about the same problem?

Here are some specifics:

  • cortex said that “motors had passed heat level three”
  • robot weighs about ten pounds
  • is direct drive with gears in a 1:1 gear ratio connecting the two sets of wheels

If you need any more info, please let me know.

Thanks!

What internal gears are you using on your motors? You shouldn’t be using anything more than 200RPM for that heavy of a bot.
You are right, the temp. levels prove it is overheating, but there are a variety of reasons for this. I’d make sure there’s nothing causing excess friction or if something is in the way.

Do you mean Brain?

The motors are too hot. Where is the motor that this refers to?

@Deicer, I’m not sure what internal gears we have as we haven’t “dissected” a V5 motor yet as we just got them this fall. Could you explain the 200RPM thing a little more?

@RoboKnight, Yes. I mean brain. Everyone at my school has always used “cortex”, so sorry for the confusion. The brain referred to both of the V5 motors that control the wheels. they are relatively exposed, with nothing over them, but a solid metal plate under them.

By default the motors have the green 200RPM cartridge in them. You can see the color right above the shaft hole in the motor. If you have the faster one (600 RPM) odds are the motor is burning out trying to get your bot to move that fast.

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What color are the little color on top of the hole the axial goes in?

100 RPM = RED
200 RPM = Green
500 (i think) RMP = Blue

Green. from what i understand, I have the 200RPM V5 motors. Correct?

yes. Do you have an external gear ratio? pic’s of the robot may be helpful

yes. Next step is to see if there is anything making the wheels harder to turn. If you want to upload a video we can help, but I imagine it is just too many shaft-structure connections gone without bearings.

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@RoboKnight No, like I said earlier, I have a 1:1 gear ratio.

@Deicer I have bearings on all shaft/axle structures. would a picture be fine? that’s all iv’e got right now.

Sure, a picture is fine. We’ll have trouble since we can’t feel the torque going in to rotate the wheel, but it’s worth a shot.

600 RPM in case you didn’t see my eariler post

IMG_20191211_074646 IMG_20191211_074547 !

you can see one of the motors in the back corner and you can also see that I used some of the bearings that came with the V5 kit on the inside of the wheel structures. sorry that it is blurry as i took the pics with my chromebook since it was the only thing I had at the time. I can get some better pics tomorrow.

I can’t quite see how the wheel pairs are connected, but I see numerous shafts sticking out of the c-channel there. More connections = more friction. (also… no bearings on them.) Unless something big is holding you up this might turn into a long search for ways to reduce friction. You might just be having issues since you only have a two motor drive.

Add barrings, and do you only have 1 motor? You may want to make it 100 RPM, or if you need speed, put 2

no, look again. there are definitely bearings. they look like this and are hidden by the c-channel:
image image
they are literally right next to the wheels.
also, the gear ratio looks like this:
image image image image image
sorry. this is the best iv’e got for you.

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It could be from mounting your 5 wide c channels inside each other. This would cause your bearings to not be aligned as some are a little high and some are a little low. This might be causing your friction problem.

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and yes. there is one motor for two wheels.

the axels do not touch the 2nd c-channel. they stop shortly after the first one.