Argh!

Technical Motors
1

This is for those teams that are using the drives and mounts provided by FIRST (using the drills).

Has anyone else tested these, because for us they dont seem to make it over the ramp very well without popping breakers. We have some serious problems now.

ARGH!

2

We are, using a slightly modified version, and have had no problems.

First check your gearing- you may be geared to high. Also make sure that the drills are in low gear

Also check the alignment of your gears and wheels. Disconnect the drill from your gears and wheels, spin the wheel and see how long it spins. If you have a lot of rolling friction you may need to realign your wheels and grease the bearings and gears. If you are using the helical gears make sure they are well greased.

3

i think the problem that you are having is due to being geared too high. still check out alignments and what speed the drill is in, if its in high then change to low and if its in low check gearing.

4

We are using the drill motors on 40 Amp breakers in low gear with cool tracks. We didn’t have any breaker popping.

http://www.chiefdelphi.com/forums/showthread.php?s=&threadid=18145

5

we litterally have the basic drive train, we hooked up to the big 9*2 wheels, which may have somehting to do with it since they are different from your team’s, but if first was so concerned with the one hour robot, why did they give us a drive train that can’t make it over the hill with an underwieght (80lbs roughly) robot?

lubing it up may be all it needs, but we really can’t do that now.

6

could you clarifiy if your using just a direct drive(no gear reduction) or using something to reduce the gear ratio. If your not then the drill motors going to have a hard time with those wheels.

7

Errr can someone tell me which position is low gear for the drill motors???

8

Low position is when the collar on the transmission is pushed forward toward the output shaft.

You shouldn’t have a problem getting over the ramp with the one hour transmission set to low. We can do it with our 130 lb bot, even with a small caster on the front (which is very inefficient on the mesh). We are using 9x2 wheels.

Eric.
Team 481
De Anza High School

9

Be sure the gears are lubricated with a sticky grease.

Turn the drivetrain by hand; sequentially removing items from the system. You may find one think mis-aligned that is causing the lion’s share of binding

ALWAYS ALWAYS ALWAYS use a fresh, fully charged battery. V=IR, low volts and these new motors become “amp hounds”.

When you hit the pits at your first regional, be prepared with a game plan to quickly and methodically approach this problem.

Good Luck

10

Low position is when the collar on the transmission is pushed forward toward the output shaft.

Thanks:)

11

could you clarifiy if your using just a direct drive(no gear reduction) or using something to reduce the gear ratio. If your not then the drill motors going to have a hard time with those wheels.

We use the helical gearset in the black box first provided

12

In your other thread that you posted in where you said you were capping the max power to the motors at 2/3. try giving full power to the motor and see if that helps.

13

In your other thread that you posted in where you said you were capping the max power to the motors at 2/3. try giving full power to the motor and see if that helps.

Oh, yeah, that may help.:rolleyes: If i remember correctly, though, we finnally set the speed max to the joystick wheel, but it’s to late now.

14

*Originally posted by Duke 13370 *
**We use the helical gearset in the black box first provided **

Are you sure that your transmissions are locked in low gear? As the earlier message said, the white collar should be pushed forward toward the front of the transmission (where the drive shaft comes out).

It might be a good idea to find yourself some smaller wheels, but be sure that you will still have enough clearance on the ramp.

Also what do you have on your other wheels? We were popping breakers in high gear (using the black motors) when we turned and found that we had to reduce side friction on two of the wheels by adding cable ties. (We have 4 wheel drive.) Basically we couldn’t turn in place in high gear until we added the cable ties. Even then, we can’t just sit there and spin in place for any length of time. The breakers start to pop.

15

Are you sure that your transmissions are locked in low gear? As the earlier message said, the white collar should be pushed forward toward the front of the transmission (where the drive shaft comes out).

Yeah, we’re sure, it may just have been a drained battery or something completly different that caused it, but i know the motors were locked in low. One of the other students (scuba_sm) found out how to lock the drives from the inside so they would never slip into high (or low, depending on how it’s done), and it works very well.

16

*Originally posted by Duke 13370 *
**One of the other students (scuba_sm) found out how to lock the drives from the inside so they would never slip into high (or low, depending on how it’s done), and it works very well. **

I am curious as to how he did that. I hope that it isn’t causing extra friction somehow. We also use a drill motor to rotate a big telescoping arm, and we just use a cable tie (“premium” with metal tabs from Home Depot) to hold the shifter in low gear. Works great.

We have experienced what happens with low battery and I doubt that it would cause the breakers to pop. When the breakers pop, you get a clicking noise, and the robot shakes as the breakers go on and off. With low battery, you just stall when you draw a lot of current, and you get a yellow light on your operator control board.

As I said earlier, I would be looking for some smaller wheels. Good luck.

17

scuba_sm put a ring on some of the inside gearing. i don’t know exactlyu what, but he was going to throw together a whitepaper sometime later.

18

*Originally posted by Duke 13370 *
**This is for those teams that are using the drives and mounts provided by FIRST (using the drills).

Has anyone else tested these, because for us they dont seem to make it over the ramp very well without popping breakers. We have some serious problems now.

ARGH! **

The FIRST supplied drive train is a big improvement to the supplied parts this year. It should be used with good mechanical practices in order to perform.

  1. There can be no binding in the shafts and the bearings have to be installed in a such a way that the bearings take all of the weight of the robot.
  2. The bearing pairs have to be aligned so that they are on the same centerline and parallel to each other. The shaft passing through both bearing must be perpendicular to the face of the bearing.
  3. The helical gears must be mounted at right angles to each other in order to minimize loading. If you can’t turn the drive shafts by hand (easily by hand) then you can’t expect the drill to be able to do it.
  4. If you are tripping or drawing lot’s of current climbing the ramp, you may need to switch to the lower gear ratio on the drill or use smaller wheels or both.
    If you are not able to machine the drive train mounting holes accurately, then you have to use slots in the chassis to be able to move the components into alignment before tightening the mounting hardware. You may have to mount the bearings in movable plates as well, depending on your design. Don’t despair because you have shipped already, you can accomplish these tasks as needed at regional events with simple tools. Ask for help, other teams are your resource. We will be glad to help anyone who needs assistance.