How "bad" are motors with "bad" stickers?
 

As mentioned by sanddrag and shyra1353 (Message #26 in the same thread), we too received a motor with a red/orange sticker with the handwritten word "BAD" on it.

When we hooked it up to the 12V battery, it seemed to work fine in both directions, plenty of torque, but we haven't done any additional testing.

Has this happened before? (We're rookies...)

Re: How "bad" are motors with "bad" stickers?
 

well the mentors who did the inventory had noticed that as well for our kit, but one believes it is a gimmick for their company to be able to send them to FIRST. **only is a thought from a mentor**

Re: How "bad" are motors with "bad" stickers?
 

We got that on our one Van Door motor they sent us, we should have gotten 2. We didn't test ti out but if you say that it works fine then I don't think we should that we should ask for another one. How many other teams had that sticker on a motor?

Re: How "bad" are motors with "bad" stickers?
 

you only get one van door motor this year, FIRST sent out an email saying that we only get 1 van door and 1 globe, the checklist was a mistake.

Also, did you try running the motor under some load? Maybe you'll see the problems then.

Re: How "bad" are motors with "bad" stickers?
 

From the FIRST e-mail blast sent out today:

Taigene Sliding Door Motor
The "Gray Container Item 5 Loose" should have contained 1 motor, not 2. The Kit of Parts list incorrectly specified a quantity of 2.
Globe Motor
The "Gray Container Item 5 Loose" should have contained 1 motor, not 2. The Kit of Parts list incorrectly specified a quantity of 2.

Eric

Re: How "bad" are motors with "bad" stickers?
 

i think they should give us the motors that the list says. they should just say o we can get them out so we will say only one. teams really need 2 van doors this year. thoes tetras are heavy.

That is easy for you to say...
 

At $20 each, that's $20,000 to add one more Globe motor to the kit and $20,000 to add one more Tiagene motor to the kit. Write FIRST a check for $40,000 and the motors will be sent out ASAP ;-)

Seriously, it is easy to say, "FIRST should have included this" or "The kit really needs that" but how many sponsors did you contact in the off season trying to get them to donate thousands of dollars worth of goods and services to FIRST?

The auto industy in bleeding red ink. I we should all be thankful that Globe and Taigene donated ANY motors this year yet alone 2 per kit - recall that in a prior message I predicted Keyang wouldn't cough up the usual seat motor this year* It is a tough time for the auto industry, we all need to think lean...

Joe J.

*By the way, this is the first year FIRST has not had a seat motor in the kit at least since I have been around in FIRST. I am pretty sure that they were in the kit in year 2 and perhaps since year 1 . FIRST historians, help me out here.

Re: That is easy for you to say...
 

2003 did not have it.

Re: How "bad" are motors with "bad" stickers?
 

Yes from looking in my 1992 manual here, Dr. Joe is correct. In 1992 the only motors that were in the KOP was a set of Delco seat motors. Except in 2003 we didnt use them either.

Re: That is easy for you to say...
 

A couple of points:

1. Listen to Dr. Joe. He has had more input with what motors are in the kit, over the years, than anyone else outside of the FIRST staff. If you complain about motors, do something about it for next year.

2. For the first time ever, teams have 6 motors in their kits with power over 300 Watts <edit: 4 CIMs, 2 F-P's>. We have never had more than 4 before. For those of you who want more power - you don't know what you are asking. We have plenty. I shudder to think what some teams can do with all of this added power.

3. 1992-2004 FIRST Competitions included the "seat motor". It was a good little motor. This magically-wound, metallic power pack spun its worm gear fast and turned many a flexible shaft. We remember it fondly. It drove our 'bot in '92, collected balls for us in '98, lifted a 180# goal in '02, and retracted a (non-used) fabric funnel in '04. May it rest in peace. /me wipes tear from eye

Andy B.

Re: That is easy for you to say...
 

Did I miss something, but I think there is still 4 motors rated over 300 Watts: that's the 4 CIMs. I thought the 2 FP's came in around 150-180 Watts, the Van door around 80 Watts, the ND Window around 45 Watts, the Jideco Window around 25 Watts, the globe around 45 Watts, and the new Mabuchi may be around 100-150 Watts (I think Paul C has this listed in a separate thread). Am I forgetting something? Where are the other two motors that are over 300 Watts?

Re: That is easy for you to say...
 

If we believe the specs, the FP motors are over 400W each. If this holds true, they are going to get hotter than Hades insummer if and when they stall or run under high torque.

And that temps gonna climb real fast!

I love the smell of burnt motors in the morning! :ahh:

Keyang and 2003
 

Yes you are right. Now I recall.

Keyang actually gave that year, but the motors didn't actually show up until the at the last moment before kickoff (you'd be surprise how many donations end up being last minute affairs). FIRST, correctly, made the choice to hold them for the next year.

That means that Keyang didn't give last year either. Hmmm... ...here's to automotive black ink in 2005, profits make everything easier...

Joe J.

Re: That is easy for you to say...
 

Last year, two of these motors were enough to lift a 130 lb robot six feet off the floor in seconds. So you should be able to easily lift 10 tetras at a time to a height sufficient to cap a goal.

You have more than enough power available, the question is "Can build a structure that can handle it and still meet weight requirements?" or "Can you build a gripper that will hold 10 tetras?"

Remember P=F*d/t

Where P=power
F=force
d=distance
t=time

Given enough time, even the weakest motor could lift anything any distance. Decide how much you want to move and how far you want to move it. Then figure out how fast you need to move it. That will tell you how much power you need.

The FPs are vastly underrated by the FIRST community at large, but those of us who have bent 1.5"x1"x1/8" aluminum C-channel with them have great respect for them.

ChrisH

Re: How "bad" are motors with "bad" stickers?
 

Check out the Q&A:
So apparently this is a special automotive meaning of BAD that doesn't mean what we think it does.

Re: How "bad" are motors with "bad" stickers?
 

"BAD" may apply to the fit rather than the function or some other problem that would prevent their being used on a production line but has no impact on our usage.

If one of the mounting holes was off for example. We would just ream out the mating hole and it is no big deal. But that might not be an option on a production line that moves every few seconds. On a properly balanced line there is no time for rework like that, not to mention that modification might make it so a replacement that was made to the proper dimension would not fit properly later.

There are probably many ways for one of those motors to be "bad" without affecting the we they work in our application.

ChrisH

Re: That is easy for you to say...
 

The FP motors are good as far as they go, however, sums them up quite nicely. During the nationals alone, we had to replace our FP motor 4 times, so, yes they have a lot of power, but I have literally seen copper melt out of the casings.

Re: That is easy for you to say...
 

Then you have been running them too hot or too slow. I design mechanisms to operate at 75% of free speed and 25% max torque. This leaves plenty of margin power (approximately 50%) and with the high rpms you get plenty of cooling air through the motors. By operating on the fast side of max power, when things bog down, you actually get an increase in power. BTW I learned this the hard way myself. I am ashamed at what I did to our poor little Van Door motors our first year. Talk about torture

ChrisH

Re: That is easy for you to say...
 

haha.

we used fp's for a winch to pull up last year. burnt out twice. verry smelly :-)

those FP's just aren't the greatest thing around...

Re: That is easy for you to say...
 

I KNEW I liked you, ChrisH. Another great thing about designing your machanism to run on the fast side of the power parabola is that the efficiency is higher on that side. That means more power turned into spinning shafts, less into heat.

ANOTHER benefit is a controls benefit. It is much much easier to control something when its free speed is only 1/3 faster than its designed loaded speed. The controller can be must less critical because the arm or whatever will not 'over run' the controls if the load vanishs (e.g. you were lifting 40 lbs of tetras and you just dropped the stack).

Joe J.

"bad" has many definitions...
 

As to the possible "BAD" labels, I don't know for sure, but I can guess.

In the auto industry, there are 1000's of specs that components have to meet, motors more than most. There are EMC specs, EMI specs, Speed, Torque, Hot, Cold, Current, Sound, dimensional stuff, and so on.

There are many many times, when an engineering change is made that affects a specific problem that is may be important to the proper function of the assembly used in a car but that does not change the function of the part by itself. For example, a grease may have to be changed in order to meet a new environmental regulation in an export market. Another example may be a change to a casting in order to clear a trim change by an OEM.

Bottom line, MOST engineering changes made to a motor would have no noticeable affect on the performance of the motor when used on a FIRST robot.

In many cases, the engineering change leaves some stock on pallets in some warehouse in the midwest. That is where I come in... ...If we can get these motors to FIRST and get enough of them to make a complete kit's worth, they end up in the Kit.

SO... ...the most likely reason for the "bad" on the motors is that there was an engineering change or some sort of sorting process needed make the system work but made no difference to FIRST and someone* convinced the motor supplier or the motor user to donate these motors to FIRST.

Joe J.

*Jim Zondag from the Killer Bees has become an expert at these type of situations in recent years. You can become an expert at this too -- PM me for details...