|
|
|
|
|
Spockie-Tech
Site Admin
Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia
|
Drill
Motors
are relatively reliable, but the gearboxes are usually
not
. At least not in the cheaper type of drills.. if you buy DeWalt hammerdrills or Panasonics or one of the $100+ ones you will probably get better gears..
They are very powerful for their weight, but it takes electrical power to make pushing power so they are also inefficient amp-sucking beasts.
If you need pushing and shoving power in light weight, then drills are good. But you will need to be nice to the gearboxes, or maybe talk to Andrew (totally recycled) about getting some of his strengthened drill motor and gearboxes.
You will also need *good* batteries to power drills through a hard 3 minute match, SLA's will struggle unless well size-matched and kept in tip-top condition.
Scooter motors are much easier on your battery and speed controller, as well as being a lot more efficient at converting amps to torque.
However, they are much heavier for their power level, are limited to one type of hard-to-replace wheel, require a specific layout for the drive belt, limiting your design somewhat, and the drive belts can be prone to breaking unless replaced with a good quality belt.
Both motors have optimum applications, it depends on what your robots requirements are. Do
you need efficiency and reliability more, or power and less weight at the cost of reliability ? There is no "best" motor for all robot designs. _________________ Great minds discuss ideas. Average minds discuss events. Small minds discuss people
|
Wed Nov 08, 2006 6:40 pm |
|
|
|
|
|
|
|
|
|
|
prong
Experienced Roboteer
Joined: 19 Jun 2004
Posts: 839
|
Hey, you can still have an effective robot that is not number 1 on the ranking
We are talking first builders here, the drill cells are a great way to get your robot going for no extra outlay.
Of course you might want to move onto bigger and better things down the track but they make a great starting point.
Your robot design and evolution is more important, a robot like Stealth could have run from drill cells, but Dumhed didn't cos he had other batteries already lying around.
Speedbump beat the leighweight running drill cells (never going to let that one die!)
Sure, you unlikely to build a high power spinner with drill cells, but that is not a great first robot anyway.
I have always run drill cells and they have never let me down. They cost me nothing extra when buying drills, I can abuse them all I want and chuck them away if they have problems.
I have seen people chuck away batteries worth more than my entire robot after shorting a pack out. I have in fact shorted a drill cell pack out, and killed it. Luckily I had about 50 spare
To me having an effective robot is not all about the rankings, its about getting a robot going, competing, having fun, learning and being able to do it within your budget
|
Thu Nov 09, 2006 10:26 am |
|
|
Spockie-Tech
Site Admin
Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia
|
Sure, having fun is the idea of the game, but winning is the name..
Winning in a mean spirited, nasty no fun way isnt likely to garner you much respect or enjoyment, however, everybody *wants* to win and when someone asks advice, they are usually hoping that your advice will help them avoid some of the mistakes you have made along the way to improve their chances of winning.
If your advice is to have an experienced competitor design your machine, buy $10k worth of off-the-shelf parts, have them assembled by Nasa, then hand over the controls to an experienced driver, chances are they wont, even although its probably good advice to win.
So what they really want is advice that will increase their fun factor (maximum reliable drive time) and their chance of winning/ranking at hopefully not too much a cost.
What is probably needed here before everyone chips in with too much advice is a *realistic* idea of the builders overall budget.
If someone wants to "go racing" with a total of a couple of hundred $ in their pocket to kit out the whole package, then drill cells are an excellent idea. you need to cut every corner you can, and they will work "ok", for a while, maybe, up to a point.
If (as mentioned in post 1) the builder is spending hours on their frame, another 300 on their ESC (IBC), another 300 on their radio (Spektrum), $100+ on a charger (which you will need regardless of cells), then some more on their wheels, drive, weapons etc. then advising them to use drill cells is
wrong
, because they will definitely be the weak link in the combination and will limit/let down the better gear.
For under another $100 you can have 2x reliable powerful sanyo packs you can count on, and slam charge back into quickly that will only be a small % of the overall cost of the bot.
If hypothethical builder B was instead working with servo switching, ebay radio's, 2nd hand drills, and other low budget gear, then drill cells would be a good match to that budget of machine. _________________ Great minds discuss ideas. Average minds discuss events. Small minds discuss people
|
Thu Nov 09, 2006 10:58 am |
|
|
|