Major problem with chipphua motors

We are having a major problem with our chipphua motors. When we try to drive the robot, if you go any faster than just barely moving, the speed controllers controlling the motors begin randomly turning on and off. This happens with even greater frequency when we try to run the motors in opposite directions to turn. We had the same problem last year, due to a short so we checked every single connection on the robot, replaced the speed controllers, and even the control board. Then we thought that the problem could be due to not enough reduction on the motor, since we used the reduction from the motor gear and the gear that came in the kit, and then atached that gear to a shaft driving a 23 tooth sprocket connected by chain to another 23 tooth sproket, which drove the 4 inch diameter pulley for our 2 inch wide treads. We thought this might have been the cause since the robot ran fine when it was up on blocks, no trouble turning or going full speed. To test this out, we removed our top section containing the bulk of our weight, about 90 pounds. With the 40 pound base, the motors still gave us touble when driving the robot, but worked fine when all load was removed from the tread drive. Has anyone else had a similiar problem or have a solution?

“Randomly turning on and off” sounds like breakers tripping(listen closely to the machine, you can hear them click)…if that’s the case, double-check your side load on the motor as well as for any flexing of your gearbox/drivetrain when it’s sitting on the ground. A system that runs fine up on blocks may flex when weight is put on it, causing binding and other problems.

We had a problem where our drive would stop on the ground and run fine on the table. It turned out that the set screws were unscrewing themselves so that the friction between the floor and the wheels was enough to cause the coupling to release the shaft from the motor and allow it to spin seperately. When up on a box or the table there was no friction (or significantly less at least) so that the set screws were still biting enough to turn the wheels. We also have had trouble due to loose chains and misaligned or tilted sprokets. If none of that works try changing the pwm cables, they may be bad or very loose.

You guys are using the same belts we our using. Nice Breco Flexs

You guy are very under power for those tracks. you will blow those breakers every time.

Our tracks are 28 in from center to center. and 2 in wide. We put 220 lbs on top of robot and can spin very easly. or pull.

We have had 8 year on these type of track and now if you have to much traction for your motors you will never get out of the blocks.

try 4 motors with those tracks and you will not have a problem. plus there are other thing you have to do to your tracks to make them work.

*Originally posted by aka Scott White *
**We are having a major problem with our chipphua motors. When we try to drive the robot, if you go any faster than just barely moving, the speed controllers controlling the motors begin randomly turning on and off. **

It sounds like the 30A breakers are tripping, meaning that either you are geared too “tall” or there is too much friction in your drive train. If you can do so easily, you might try gearing lower and see how things work.

This is our third year using tracks. Remove the chain from both motors with the robot on blocks. Spin the tracks by hand, they should move real easy. If that passes the test, set the machine on the floor with full weight and push the bot against the friction in the tracks. If this passes muster, then the problem is located in your gear reduction or motor mount. Use a DC ammeter to check current when the robot is on the blocks, that will tell you alot about excess friction or binding. Our bot for 2001 used two bosch motors and two FP motors, one of each directly driving the track (two inch timing belt with 3" pulleys). We found that you could still drive the bot even with 2 dead FP motors still coupled to the tracks. That is a lot of extra load. The bosch motors were in low gear with a 1 to 1 ratio to the 3" pulleys, roughly 5fps with no load. If you are geared for real high speed, that could be your problem as well. Speed is good, but not if you can’t do anything when you get there.

http://www.chiefdelphi.com/forums/pictures.php?s=&action=single&picid=2036&direction=DESC&sort=date&perrow=4&trows=3

This show how we set up the two motors for our track drive and

http://www.chiefdelphi.com/forums/pictures.php?s=&action=single&picid=2176&direction=DESC&sort=date&perrow=4&trows=3

this is the track drive. We been doing this for 8 years.

you might have everything to tight. loosen up the tracks.

Spin the tracks by hand, they should move real easy.

you should be able to do this.

the tracks if pushed on the floor should glide without the motors on them.

Okay man you are binding up the drive system my guess is that you are using the reduction gears in the kit pressed onto the motor output shaft. Those gears and any gears are made to have some play in the teeth when they mesh so lighen up the pressure on them a little bit. This is just a guess and it happened to us when i first built the transmission but I fixed it easily. If this is not it then feel free to call me and I will try to figure it out step by step. Number is 276-686-5142 ask for Jonathan

We had almost the exact same problem this weekend. Glen from team 60 offered a suggestion that this years battery charger wasnt giving the batterys enough amps. So he switched one of his teams batterys charged with last years charger and it work perfectly.

He also told us that us leaving our batterys on the shelf for 8 months uncharged ruined them and we need to renitrate them. I have no idea what that means if anyone could help out that would be great.

Also check to see if you get a low battery light. We had a problem like that at the VCU regional and ended up taking of the chiaphus(and it worked.) Otherwise i agree with Nate, that seems to be the other most logical occurence

it really doesn;t matter at this point but our team is having the exact same problem. a solution that was thought of is something that I have a question of legality. is it leagal to use 2 speed controlers for each motor that way it really doesn;t change the way it drives but will give you double the aprage. it was an intersting thought that we had after regionals and since we arn;t going to nationals it doesn;t matter that much. we were just curious if this is leagl and/or will it work

*Originally posted by tarbell *
**it really doesn;t matter at this point but our team is having the exact same problem. a solution that was thought of is something that I have a question of legality. is it leagal to use 2 speed controlers for each motor that way it really doesn;t change the way it drives but will give you double the aprage. it was an intersting thought that we had after regionals and since we arn;t going to nationals it doesn;t matter that much. we were just curious if this is leagl and/or will it work **

Is it legal? No

Will it work? NO…the internal electronics of the speed controller cause a pulsing power stream to be sent to the robot(i.e., not 6v, but 12v half the time - it’s been discussed here before)…there is no way for this power pulse to be syncronized between the two speed controllers, so catastrophic failure of one or both controllers, and perhaps the motor, will result if you try this…

Once you’ve tripped those 30 amp. thermal devices a number of times, they seem to trip at lower and lower currents. This comes from past experience with the devices. I think the continuous heating lowers the spring rate that holds them in the closed position. We keep a good supply on hand and throw them away after a series of trips and we never reuse last years.

Just a thought!

Tim Gates
Team #288

I agree with the Dawg - once the 30 amp breakers start tripping, they do it more and more frequently. I have seen this for three years now. I don’t know what goes on inside to make them do this, but it sounds like you need to get a big supply of them.

This sounds like a breaker problem if I ever heard one. Something is causing your motors to stall, causing them to draw far mroe current then normal. Check for side load on the shaft coming out of the motor, that causes stalls very easily. You may just not be geared enough for the tracks you are using. Also, as far as the breakers go, any breaker is more likely to trip when they are “hot”. A breaker that has tripped or repeatedly been pushed to near tripping without being given cool down time will trip much easier.

We had this problem. Especially after hitting a goal our motors would stop and start randomly. We replaced the sprokets on our drive wheels with ones of almost twice the diameter and the motors never gave us trouble again. We figured out to do that after swapping the breakers with new ones, double checking wires, swapping pwm cabls, and even switching victors to verify where the problem was.

*Originally posted by Leo M *
**I agree with the Dawg - once the 30 amp breakers start tripping, they do it more and more frequently. I have seen this for three years now. I don’t know what goes on inside to make them do this, but it sounds like you need to get a big supply of them. **

Probably the contacts in the breakers oxidize from the arcing each time the breaker trips, resulting in more resistance at the contacts and more heat being generated at the same current flow. This additional heat will make the breakers trip earlier at the same current, and trip at lower average current.

Yeah, what Kit said makes sense. If you happen to have a 30 or 20 amp breaker the you tripped a lot you probably want to replace it. I don’t think they were designed to cycle tripped to on that much.

we figured something out and it worked well for our public viewing today just thought I would let you all know. first of all we did a voltage scan program so we would know the exact voltage every motor starts at and then went and changed the opp program to assign thoses voltages with the motors so all the wheels start at exactly the same time. this helped alittle because it reduced drag. the second thing we did was put in a “jerky motion reducing program” atleast thats how it was described to me. what it does it when control changes are very sudden the type that will make your robot “dance” it averages the data input and smooths out the driving. This works well because it is the instant change/high ouput in voltage that is tripping the breakers. well thats what the softwear people told me. I’m sure that I could get a copy of the code if anyone wants it
greg