Testing for Motor Modifications

I cannot find another thread on this, so here is the white elephant in the room. At Worlds this year there were MANY teams in the middle school division and some in other divisions who were caught with modified motors (by-passing thermal overload circuit). There were rumors floating around but nothing official was ever said about it. Some teams were given a penalty of two matches some sent home. What was the difference? Personally all teams caught should have been kicked out on the spot. What other sport gives you a slap when caught cheating. In school you are expelled!

We come from a club who consider a rule as the law. When told ahead of worlds that this was going to be checked for and then have over 20% of teams (yes 20% per a judge in middle school division) show up with illegal motor modifications, I am concerned. I am more concerned when told directly from some clubs that they have been doing this for years, and those are the same clubs we go up against at national tournaments. How can a team be proud of the fact that they are successful when they have cheated to obtain their success?

How do you get kids to trust in competition again? This will be on their minds whenever they see a robot that seems to have that extra power and never blows circuits. Are they that good or did they cheat? At worlds they did random check and did catch additional teams. But this process did hurt some legit teams as their motors were all overheated due to the check and therefor blew circuits when they normally would not. Robots with “smoking” motors were observed, but not checked.

If this is not handled soon the trust of competition is going to suffer. Do teams want to pay the entrance fees and travel expense to go against teams that may have an unfair advantage over them? I am guessing not. If this situation was difficult to handle at a World level tournament, how do we manage regional tournaments? How can the test be modified and more easily test motors? With a slap on the hand I don’t see this situation going away any time soon for teams that were caught at worlds.

Please chime in on this so I know if others are feeling the same way about some bad apples spoiling the great things that this environment can offer.

Thanks for this post.

I wholeheartedly agree! I would add that any coach/mentor that supports this kind of behavior should be banned from the competition for life! I know that the majority of the teams/coaches/mentors are honest and I do so appreciate that. I feel that the only way to rid the competition of the bad apples is to be swift and harsh with the punishment.

If my kids learn one thing during these formative years I would hope it to be that they should always act with integrity!

While I agree with the sentiment, how do you go about enforcing this? You can’t just ban the team or team number or whatever because otherwise Team 1234 just registers as team 1235. You could have a blacklist with pictures of all offending coaches/mentors that you post somewhere and hope people at events bother to check it, but the coach/mentor could just not show up to competitions.

I think that officials should somehow test at least one motor and if it is modded that that team should receive a penalty of some kind. Nothing too severe unless it happens multiple times. Maybe they would have to be on cool down and have to miss a tournament… I don’t know but i really don’t want to go up against teams that have like one million rpm! Lol :eek:

I’m going to have to go out on a limb hear and disagree with you, our team and several others that we know test their motors with tests similar to how the refs at world championships this year did, only were looking for the motors that fail at the highest levels. We go out and select the most powerful motors to help us with stalling, however all of our motors are 100% legal, they came like that out of the box. Through this we have found that out of the box, motors actually have wide range of strength, its not like they all have the same power, some are more powerful then others. Some teams that we know who did this strategy actually got flagged for illegal motor modifications, even though they were the same motors that vex sold them, just the ones from the higher end of the spectrum. The test they used at champs was not all inclusive of the motors that vex sells people, had they checked every motor for every team, a lot of legal motors would have failed. Either the test needs to be changed or the rule needs to be removed, it’s far from definitive enough to justify a total dq of a team. Additionally we found that after one of these tests the motors can take up to an hour to cool off completely, some teams who were checked during elimination matches were forced to play with motors that had just been checked, stalling only a few seconds into the match… There is a lot that needs to be changed with this test, i agree with its concept but not at all with how its being done.

You are correct that there is a range of quality, and how they were tested at worlds was not conclusive. If a motor is tested and fails, and once opened shows the soldered applied to bypass the circuitry, the team should be kicked out of the tournament. If there is a proper test, some labeling or mark made on the motor, then changing motors would require that changed motor to be tested and marked. At least it would help with subsequent random checks. So unfortunate that this topic is even a topic. Shame on those that partake in this sort of play, and you know who you are. If getting a trophy is so important to you, I will buy you some but stay away from the tournaments.

i have to agree with both sides of this. Teams who have put forth the effort to select the better motors just like many major corporation that produce electronics(Intel, AMD, micron… a process called binning if you are interested) should not be penalized for having better motors. The testing should not affect their performance in matches.

On the other hand there should be little tolerance for true cheating. I agree that if multiple true violations are found then the team should be asked to leave the competition.

Also i don’t like the nature of the test because it has the potential to damage the motors even when performed as outlined.

We had problems with the motors that were “tested” at world just like many other teams. I think the test needs to be improved or they need to give replacement motors for the motors that are tested.

We had the same issue for our C team in finals of the technology division. We were checked twice, once before semis and once before finals. I in no way think this is why we didn’t win the finals match but it sure didn’t help as motors overheated in the first match of finals. We were the QF 4, and SF 2 so as the matches went on we went from a match, to a test, to a match with no cool down time. Not to mention my students barely had time to think between SF and Finals, they definitely didn’t have time to swap motors.

I am thankful for all VEX does to ensure all the rules are followed and we will always pass the tests, we will never be on the cheating side, but there has to be a better way. This also in no way will ever keep us from attending worlds if we qualify!

They checked ALL of ours at inspection. I don’t know if that was standard or not, but the guy had me pull every wire out of the Cortex, and then proceeded to stall test each one. We were never stopped for a spot check during matches either, although that may be because it was really obvious we were stalling motors in nearly every match.

Was that not what happened to everyone? I didn’t get a chance to ask people about their inspection processes.

Our teams were also checked multiple times throughout the event.
The motor check tests how many seconds it takes your motors to trip the PTC in a stall condition (roughly 5 amps of current). This test is a useful test because you can document the quality of your motors.

  1. If PTC trips in less than 3 secs, that PTC is more likely to stall in a match
  2. If PTC trips from 5 - 10 secs, that motor is on par with a normal motor.
  3. If PTC does not trip (that’s when the inspectors start asking questions), you also risk blowing your cortex motor ports.

The more you trip the PTC, the worse your motors will get over time. The motor test gives teams a warning to possibly change out to new motors.

They picked two motors at random on our robot and checked them at inspection.

Didn’t get checked again after that.

I wasn’t at worlds, but OYES were checked six times by halfway through Friday after which I think they stopped updating us when they got checked.

Turns out if you build an 8 motor 1:3 drive on a 15" aluminium robot, people start to ask questions.

STEM Villains Hall of Shame? (only sort of kidding)

That sounds like a slap on the wrist to me. Swift and harsh gets results.

I will gladly pay for half that trophy.

Thank goodness for teams like yours!

I was helping out with OYES for the weekend and I think we were checked 7 times by the end of the weekend. If we had made it through our semifinal we were told we would be checked again prior to entering the dome. The PTC checks were definitely understandable, especially considering the number of teams that were eventually caught, but being checked so many times on the same robots (eventually had all 8 motors on the 8 motor drive checked) got pretty frustrating.

I wonder if pre-heating of motors due to their being tested might explain why the middle school final match competition looked so pathetic. My kids were expecting some sort of intense whirlwind competition at the final match, some sort of show of force, but instead it was perhaps the lamest match we had seen all day. It looked like Amateur Hour compared to many other events my kids had been through. Even the finals autonomous portion looked like it was operating on sleeping pills or something. Did their motors get pre-heated or was something else going on there? :wink:

I know I was baffled by the sight of a few middle school kids running panic-stricken back to their pits on thursday morning with their arms loaded with new motors they had just bought from the store. Did they really need to swap out all their motors? :eek:

On the other hand, a team I trust told me that one of the motors they had used for months had failed inspection and needed to be replaced. They were flabbergasted that their off-the-shelf motor had not passed the inspection test.

In any case, I would be interested in seeing how variable the motors can be when taken right out of the box. Somebody mentioned their team employs “binning” to get the best motors, picking the best motors from a pool of unmodified motors. I would be interested in knowing what the distribution curve on performance looks like. Are we talking 10% variability or is it more like 50% or what?

I wish I could get my hands on that motor and make my own measurements.

I’m not going to comment too much on what transpired at worlds as I was (indirectly) involved with the testing and it would’t be appropriate. However, I have probably spent more time testing PTCs than anyone else on the forum and can at least make these comments.

  1. PTCs can vary widely, I’ve seen a 2:1 difference in trip times at 2 x hold current. Less so at 5 x hold current.

  2. The data sheet for the motor PTC shows a maximum time to trip of 5.9s at 4.5A. A few devices will take this long, depending on the experience of the inspector and the actual current applied (it could be less due to voltage drop at connections etc.) I could see a longer time than this happening very occasionally.

On this note, I would like to take this opportunity to thank the VexU field tech (I didn’t catch his name I’m afraid) who had to go through testing our motors 5 or 6 times! He made the process a lot less frustrating than it could have been, we appreciated the friendly treatment and consideration. At least I’m pretty sure now after passing 7 times (once at initial inspection too) that we weren’t cheating? The best part was our surprised reaction when we were told that for once we WEREN’T going to be tested after playing a match!

As for those concerned about the method of testing damaging their motors: I can pretty much guarantee we were tested more times than you, and we didn’t notice any deterioration in motor performance, so your concerns may be misplaced. :stuck_out_tongue:

I’ll try to get in contact with their mentor tomorrow and see if they kept it. I’m guessing they would like to know what was going on with that motor, too - if anything.

This post has been a learning experience for me. I never would have guessed that the motors could vary by so much. Now it makes me wonder if my kids shouldn’t start “binning” motors, too. Unfortunately, when you need 4 motors and you have money for only 5, such extravagances become out of reach for most of us. :slight_smile:

By the way, despite all the weird things that might have gone on with motors and alliance selections, my kids had a great time at Worlds and they are totally stoked to earn a position there again next year with this new game.

Do you believe there’s a better way to test for modified motors?

I’m not actually sure how our robot got inspected during inspections, but for our 10 motor base, I don’t remember going through more than the initial stall test.

Clear motor casings?