OK, we’ve finally got the go-ahead to use recycled automotive motors. As per [R48] They can be “up to 2 window lift, seat, windshield wiper or door motors obtained through either the FIRST-Automotive Recyclers Association partnership or from a prior years’ KOP.”
This is a excellent opportunity to get a better motor for that power shooter, etc.
How do we determine what are good (low weight vs high power) candidates for this or any other robot application?
Other than trial and error, I’m not sure where to start. Little or no specifications are typically listed in car manuals or even on the motor itself.
Anyone have any experience or connections to figure this out a bit more scientifically???
Do you really want to use a recycled motor on your competition robot, where you have no idea how much it has been used, or hanging around? Might be OK for practice bot or prototyping. You are right though, in that you might find one that is more powerful or in between those that are offered in the kit as a more effective choice. what about having spares if you do use them. the rules say nothing about obtaining spares.:yikes:
If you’re getting a motor from a car, I sure hope it would be in good working condition (unless it’s coming from a very old car). I don’t know about you, but I expect my door locks to last the life of my car…being on a FRC robot shouldn’t kill them so easily.
If, for example, I determine that a particular GM seat motor is good, I could use a seat motor from a 2011 model GM car. Recycled does not necessarly mean old or unreliable.
The donation from the ARA is for 4 “free” motors, of which you can use 2 on this years robot. That’s 100% spares. If you want more spares, there’s nothing stopping you from getting more simply by paying for them.
The OP asked how to figure out what would be most powerful, also considering weight.
You can’t do this scientifically, at least not easily, since specs are hard to come by. So, we take an empirical approach.
Window motors will be the weakest. Seat motors will be almost as weak. Door motors are only used in certain vehicles, but they are more powerful. Wiper motors are in every car, and are generally most powerful, but not always. Bigger cars have bigger wipers, which need bigger motors. Luxury cars don’t have to design as close to the financial limit as economy cars, and they make their reputation with longevity.
The most massive wiper motor I have ever seen is from the Mercedes models that use a single arm to wipe the whole windshield. These are E-Class cars from 1986-95, and the newer E-Class from 96-2002, along with the S-Class 92-99 and SL 1990-2002-ish. There are others, but those I’m familiar with, and those models are plentiful.
One thing to keep in mind is that window, seat and door motors are not designed for a 100% duty cycle. Wiper motors are.
The strongest motors you will find will be those for Ford and GM Suv’s and Chrysler minivan’s “5th door”. Those have to lift a ~100lb “door” w/o the benefit of much leverage. Can’t say I’ve ever messed with one and held it in my hand though. As long as the recycler writes door instead of hatch on the receipt they should be legal, guess it depends on their and FIRST’s definition of the opening on the back of such a vehicle.
Sliding door motors do move a heave door but they are sliding on tracks not being lifted.
Next will be window motors from older GM and Ford cars, up to late 80’s/early 90’s depending on model, they have near CIM sized motors and have to work against a very strong spring to lower the window and their mechanisms are kind of crude. Pivots are often steel on steel w/o grease after the first few years. Both are quite durable too. The problem is that they incorporate a safety feature in their drive mechanisms to limit torque. In the Fords it’s a plastic gear that wears out and gets brittle with age as do the “rollers” that transmit the power to the output gear. Their failure rate is so high that you can walk into most auto parts store and find the gear set in the HELP! Section. Depending on the model line they are found in up to early 90’s vehicles.
Seat motors from the older (similar age range as the window motors above) GM and Ford cars are also quite large, again they are near CIM sized and the tilt/height motors work with little leverage to lift hundreds of pounds.
Wiper motors aren’t a good choice IHMO, often they are grounded through the chassis since they aren’t intended to be reversed. The park function could be useful for some applications though but could make for problems should you want to try to reverse it. You will want one from a vehicle that doesn’t hide it’s wipers under the hood as they often have a secondary gear train so they stay in the “up” position when used on the intermittent function. Also note that many have an unusual way of obtaining low speed. Power is required on 2 wires for low speed and 1 wire for high speed. Many late model GM wiper motors incorporate an on board processor to read the resistance of the switch circuit in a particular position to determine it’s operation.
Don’t forget the most important part about 4.1.8 section I.
I. up to 2 window lift, seat, windshield wiper or door motors obtained through either the FIRST-Automotive Recyclers Association partnership or from a prior years’ KOP
emphasis mine.
and I would have no problem using used motors taken out of salvaged cars.
Has anyone contacted a recycler listed and get a usefull conversation from them?
Did anyone get any motors?
Or is this another " Looks great on paper, but in reality was just a Gimmick by FIRST with no substance".
disappointed that there was not a single location to get the surplus motors. The one I called said to come and take it off myself - they could not be bothered!
I haven’t gotten any yet , but was planning on making calls this week. Has anyone found any cool motors? I was thinking a liftgate motor might be a neat motor to try.
Keep in mind that most, if not all, power lift gate motors are assisted by gas struts on a minivan. So they aren’t really lifting all that weight by themselves, just like you don’t when you use a non power lift gate.
Mike,
I called Schram GM Auto Parts in Waterford during the first week of the season and the one person I talked to said it was new to him. He encouraged me to bring the paper certificate about the program in to the store.
So, I guess, a word to the wise - check your source of recycled parts because the whole FIRST motor recycle program may be new to them.