Team 151 Needs a little help,
We are looking for current drill motors. Last year we used the van doors for drive and were not impressed. After a drive fiasco(sp) in 2000 when we burnt up every drill we had we are left with zero current drill motors. We are looking for a place to purchase the new drills and transmissions or a team in the north east with an excess of them. thanks for any help.
tyler forbes
151
Our team also burned out our drill motors last year. We purchased two extra ones from the company listed in the back of the manual. From what I heard, there were no problems getting extra motors. They arrived in small boxes in a few weeks. Our faculty advisor mentioned that they were “cheap”, though I suppose that is a relative term.
The listing I have for the company is:
S-B Power Tool Company
121 Corporate Blvd
South Plainfield, NJ 07080
Phone: 908-769-8208
I could send you a few transmissions but I need the motors, e-mail me if you need the tranny’s at matthew.reiland@gm.com
it seems that all we need is the motors as the transmissions as the same. (checked model numbers). i did happen to find one working 1999-2000 drill motor. were the 1999-2000 and 2000-2001 drills the same? if so i should be all set. thanks for any help.
tyler forbes
151
My team also burnt out a few drill motors recently. We called FIRST to ask them where to get the motors and they said they had surplus from last year. We got 3 motors from them without even paying shipping! I don’t know if they have any left. If they don’t , email me and I’ll try to get send you one of ours.
*Originally posted by Kai Zhao *
We called FIRST to ask them where to get the motors and they said they had surplus from last year. We got 3 motors from them without even paying shipping
… if FIRST has a surplus of drill motors to give away, does that mean that they are not going to use them this year?? Just a bit of speculation - I don’t see why they couldn’t give away one year old never-been-used drill motors if they were in the parts kit this year.
~Tom Fairchild~, who thinks that not having drill motors would definitly make some teams do more work - including his!
I heard that those drill motors have been discontined, so they may not appear in the kit this year. I assume that there will be a reasonable substitute if they are absent.
I’ve noticed that FIRST have been using the Bosch 3310 drills before, and that last year we actually got the 3315. Now, that could mean that the 3310 was the model Bosch stop producing, and that we will be using 3315 from now on.
Those two model have pretty much identical specs, although the cases are different…
So I won’t be so sure that FIRST will stop using Bosch drills, but then, most of the hand drills have pretty much the same designs.
Maybe they will use a motor where putting a fisher price motor on the back won’t be possible anymore. 
Now that will make a difference.
I still wish not every robot next year will be using that dual motor design.
*Originally posted by Ken Leung *
**I still wish not every robot next year will be using that dual motor design.
I doubt that every robot will use this design.
Our team gets many inquiries about this design, but many teams will still do their own thing, because of a variety of reasons:
…1. They don’t believe that this design works, and they don’t have the time to prove to themselves that it does.
…2. They want to do their own thing. So, they take this design and modify it for their own liking.
…3. They don’t have the fabrication equipment to make the parts accurrate enough.
…4. They are not sure that these motors will be provided in next year’s kit.
…5. They already have their proven motor designs for their drive base (if it ain’t broke, don’t fix it).
All of these reasons are valid to a certain level… some more than others. The biggest argument I have is with #3. Teams automatically think that they have to meet the tolerances signified in these prints, but in actuality they don’t. In order to get one of these things built, you get the parts made as accurrately as you can, then you tweak the parts (file, shim, whatever) to get the assembly to run w/o too much wobble.
Even so… I predict that only 5% of teams will use this design on their robot.
Still… even IF all teams used this design… it would be a good thing, in my opinion. The main reason why we published this design is simple:
This will increase the level of competitiveness of FIRST robots.
Andy B.
Since I first started doing FIRST the motors have gone from:
1996:
2 Milwaukee drills
4 Delco seat motors
1997:
2 Skil Drills
4 ITTA seat motors (ITTA bought Delco Products)
2 ITTA window motors
1998:
2 Bosch Drills
2 Globe motors 2 Bosch power sliding door motors
2 Keyang seat motors
(Keyang makes a less expensive bolt in replacement of ITTA seat motor)
2 ITTA window motors
1999:
2 Bosch Drills
2 Fisher Price motors/gearboxes
1 Taigene power sliding door motors
(Taigene makes a less expensive bolt in replacement of the Bosch power sliding door motor)
1 Bosch power sliding door motors
2 Globe motors
2 Keyang seat motors
2 Valeo window motors
(Valeo bought ITTA)
2000:
2 Bosch Drills
2 Fisher Price motors/gearboxes
2 Taigene power sliding door motors
2 Globe motors
2 Keyang seat motors
2 Valeo window motors
2001:
2 Bosch Drills
2 Fisher Price motors/gearboxes
2 Bosch power sliding door motors
(Bosch was convinced to donate the motors)
2 Globe motors
2 Keyang seat motors
2 Valeo window motors
1 “Torque Motor” (hardly worth the bother)
2002:
Much that is the same
Much that is new
As you can see there have been a lot of changes to the motors in the kit in the last 6 years. There will surely be changes in the future.
Can’t wait for the kit and game to be unveiled.
Joe J.
P.S. I may have had one or two details messed up above. Memories get all confused as time marches on and there is so much to keep straight in my head. With the exception of the Torque Motor, I have personally played a role in every motor in the kit by either begging my management to buy the motors for FIRST or by begging and pleading with the motor suppliers to eventually convince them to (fully or partially) donate the motors to FIRST. By the way, much of FIRST works this way. There are many many folks working behind the scenes making sure that FIRST is successful. Think of these folks when you stand and clap at the end of a FIRST competition.
*Originally posted by Andy Baker *
Our team gets many inquiries about this design…All of these reasons are valid to a certain level… some more than others. The biggest argument I have is with #3. Teams automatically think that they have to meet the tolerances signified in these prints, but in actuality they don’t. In order to get one of these things built, you get the parts made as accurrately as you can, then you tweak the parts (file, shim, whatever) to get the assembly to run w/o too much wobble.
Even so… I predict that only 5% of teams will use this design on their robot.
Still… even IF all teams used this design… it would be a good thing, in my opinion. The main reason why we published this design is simple:
This will increase the level of competitiveness of FIRST robots.
Sorry, i’m a newbie to these boards. What design is this?
*Originally posted by ahecht *
**Sorry, i’m a newbie to these boards. What design is this? **
http://www.chiefdelphi.com/forums/papers.php?s=&action=downloadpaper&paperid=21
It’s a motor assembly that the TechnoKats designed, and it couples the Fisher Price and Bosch Drill motors together so that they work in tandem.
Thanks for the links. One thing I don’t understand about the design though: Is the FP motor actually rotating the drill motor?
What happen in the design is that the Fisher Price’s output shaft is attached onto the back of Drill motor’s output shaft. So, together, the two motors push on the combined shaft, transfering both motor’s mechanical power into the drill transmission, and eventually onto the wheels.
That is why there’re two nut shape attachment on each of the output shaft, and a coupler joining them.
So, this is really a 4 motors drive train with a conventional tank design. The only draw back is that there is no room for gear reduction on the fisher-price motor to change it into the same speed as the drill motor…
I don’t think you need to. One normally runs at 100rpm and the other operates at 90rpm, so they are close enough that they both should run at 95rpm without any trouble or tweaking.
Under no load, the drill motor itself runs at 20,000 rpm, while the fisher price run at 15,000 rpm…
The 100 rpm is only when the motors have their own gearbox reduction attached. But in this case, the two motor is directly attached at their output shaft, so they would want to match the two motor’s speed or else one motor will be dragging the other along…
So in this case, the drill motor will need to reduce it’s free speed to 15,000 rpm… Is this right? that’s like 3/4 voltage, which is 9v…
*Originally posted by Ken Leung *
**Under no load, the drill motor itself runs at 20,000 rpm, while the fisher price run at 15,000 rpm…The 100 rpm is only when the motors have their own gearbox reduction attached. But in this case, the two motor is directly attached at their output shaft, so they would want to match the two motor’s speed or else one motor will be dragging the other along…
So in this case, the drill motor will need to reduce it’s free speed to 15,000 rpm… Is this right? that’s like 3/4 voltage, which is 9v… **
Ken, you are close. Your above statements are all correct, until you get down to thinking that the drill motor’s free speed will need to be reduced.
Look at it this way: no motor under an applicable load will reach it’s free speed.
I’ll try to explain:
Let’s initially ignore that the F-P motor is on this assembly. The Drill Motor is attached to it’s gearbox, and it is turning a sprocket. This sprocket then drives a chain which drives the wheels. There is much friction, drag, and mechanical loss going on after the torque is transferred to the shaft leaving the Drill Motor gearbox.
The different types of friction losses range from friction in bearings to friction in propelling the robot across the carpet. With all of these losses added up, the Drill Motor’s speed might get to 1/2 its 20,000 rpms… and that is if your drive train is aligned properly.
OK… now we can figure in the Fisher-Price motor. Considering that the Drill Motor is grunting away at 10,000 rpm without the F-P motor, it gets a “boost” when the F-P motor gets added to it’s backside. Ideally, this “boost” can last until both assemblies get up to 15,000 rpm, since that is the F-P motor’s free speed.
Now, above 15,000 rpm, the F-P motor begins to become a drag to the assembly… but we don’t really care at this point. At 15,000 rpm, we already have a 50% speed boost.
I am not sure where our final rpms were peaking on this assembly, but we do have some evidence that it was around 14,000 or 15,000 rpm. Here is our proof:
Our top speed was around 8 or 9 ft./sec. This translates back through all of the reductions to the motors running at 14-15,500 rpm.
Also, we noticed that the F-P motors got hotter than the Drill motors after being ran a long time. This means that the F-P motors are being maxed out while the the Drill motors may have more to give… making us think that we are getting close to the free speed of the F-P motors.
And… this assembly is almost the same as the assembly we used in 2000, except with the F-P motor added. We also used the same ratios (approximately) from the motors to the floor as we did in 2000. In 2001, we saw a 40% speed increase. This would agree with our assumptions that we ran 10,000 rpm in 2000 and 14,000 rpm in 2001.
We have not put this assembly on a dyno, but we plan to over the holidays. Once we get some results, I’ll post them.
Andy B.
Andy,
I disagree with you about the typical free speed of the drill motor. If your system has so much drag that the motors are topping out at only 10,000 rpm, I think something must be wrong with your drive.
Seriously, that would mean that wind and friction are driving you to half your free speed. In this case, each drill motor would be drawing half its stall current (60-70 amps) when it is running at top speed. I seriously doubt that this is the case. If it is, again, I think something is seriously wrong.
As to what happens when you put 2 motors with different stall torques and free speeds on the same shaft, there is no magic here. At any give speed, the torques add. If you plot the speed-torque curves with torque along the X-axis (as every right thinking person does all you need to do to get the aggregate speed-torque add the torque from each motor at each speed.
Since everything is linear, you only need two points to define your line. One point can be the zero speed torque = Stall Torque of motor1 + stall torque of motor2. An easy second point is the free speed of the slower motor. At this point the aggregate torque is the torque of the faster motor at the slower motors free speed.
Notice that at speeds faster than the free speed of the slower motor, the aggregate torque is LOWER than the torque of the faster motor alone. Why? Because some of the torque from the faster motor is going to make the slower motor spin faster than its no-load speed. The slower motor is acting as a brake! It only makes sense.
My two cents worth.
Joe J.
P.S. As to why the F-P motor was hotter than the Drill: There are a number of reasons for this. The simplest is that the cooling of the F-P is just that MUCH LESS efficient. The F-Ps get hotter even though the drill motor is providing more power and doing it less efficiently than the F-P (by this I mean the it requires more electrical power in per unit of mechanical power it gets out – the difference turns up as heat that must be dissipated).
There are 2 main reasons for this. Number 1 is that the surface area of the F-P much smaller. Smaller surface areas for dissipating a fixed amount of thermal power drives up the temperature. Number 2 is that the cooling fan is much less effective. The tip velocity of the fan is smaller and the fan blade size is smaller. Both of these mean that the temperature of the F-P is going to be higher.
Another reason that the F-P may be getting hot is that when it is acting as a brake, it is generating heat. This heat also can be a contributing to the higher temperature of the F-P motors.
Finally, this is one thing that many folks miss: the “factory” motor mounts allow air to flow through the motor from the shaft side along the axis of the armature through to the electrical side with the fan on it. This is true on both the drill and the F-P. Many “homebrew” designs block this flow. If you are blocking the flow on the F-P but leave the drill motors as is, that is even more reason why the F-P motors would be hotter than the drill motors.
*Originally posted by Joe Johnson *
**Andy,I disagree with you about the typical free speed of the drill motor. If your system has so much drag that the motors are topping out at only 10,000 rpm, I think something must be wrong with your drive.
Seriously, that would mean that wind and friction are driving you to half your free speed. In this case, each drill motor would be drawing half its stall current (60-70 amps) when it is running at top speed. I seriously doubt that this is the case. If it is, again, I think something is seriously wrong.**
Joe,
You misunderstood what the 10,000 rpms represent. The 10,000 rpms I referred to not free speed, but rather the speed of the motors while the robot is at top speed. The friction I mention not only includes losses in the drivetrain, but also losses due to a 130 lb. robot being driven around the carpet. Maybe I should call this “peak loaded speed”.
What you mention on the torque adding is similar to what I discuss. It suprises me that many people get hung up on the fact that IF the speed is over 15,000, then the F-P motor acts as a brake. Yes, this is true… so they shouldn’t design their ratios so that they are exceeding 15,000rpm. As long as 15k is not met, then the F-P motor is adding a boost.
As for the motor cooling info… that makes sense.
Andy B.