Re: Why Hasn't first gone Brushless?
 

I understand the cost Of it, not saying that they would need to be supplied in the KOP, but why not make them legal. I dont see anyone complaining about the cost of the cRio's....:rolleyes:
They aren't cheap either but everyone benefits from them

At only 337watts the cim motor is not THAT powerful of a motor.. The Brushless system of my Brushless rc car puts out more then double that. If you wanted something comparable to the cim in brushless form, it would be half the size and the only thing needed to use it are shaft adapters which can easily be made.

As for price, Not every system you look at is that expensive
http://www.hobbycity.com/hobbycity/s...idProduct=7392
Take for example, that motor 30 bucks, and rated for double the power and more then the cim.

Before everyone jumps to conclusions about price and effectiveness, do some research- things are always not as they seem.

Re: Why Hasn't first gone Brushless?
 

Historically, FIRST hasn't allowed non-kit motors. The lone exceptions in recent years have been for the CIM motors, where two were provided with the kit (and a total of four would be legal). I'm sure someone with more time under their belt can expand on the idea behind that decision.

The CIM motor is powerful enough to power nearly any manipulator a team could need, and more than powerful enough to tackle a person (or whack them in the chin--don't ask). If it's enough to let us send a robot screaming downfield at upwards of 10 feet per second, do we really need more power? Also, never rule out the importance of those shaft adapters--someone has to make them, and that takes money.

Also, perhaps someone can enlighten me about this: how durable are these motors compared with motors currently in the kit? Sure, they might be more powerful--but that's no good if they burn up when stalled for a tenth of a second, or are particularly intolerant of abuse during assembly and testing. I missed out on the brushless era in R/C trucks (I quit racing when I went to college), so I'm unfamiliar with the state of the art these days.

Re: Why Hasn't first gone Brushless?
 

The motors provided in the KOP's are fine and easy enough to deal with. The fact that the motors and accessories are under so much restriction is a plus in my opinion because it's one elss thing that a team has to worry about. We just need to learn how to deal with the restrictions and constraints. Plus, it makes things much more fun and interesting :)

Re: Why Hasn't first gone Brushless?
 

The problem then is, as pointed out by multiple people earlier in the thread, it widens the gap between the "have" and "have not" teams. Motors have typically been (aside of additional CIMs and spares) provided in the KoP and teams have only been allowed to use the provided KoP motors. This ensures equality, as well as helps teams learn how to effectively use provided resources.

Nobody hear said that the CIM is that powerful, but it is powerful enough for virtually any FIRST application. Even in carpeted games, a two-CIM per side drivetrain through a transmission can produce more than enough force to break traction wheels loose from the floor. Once you surpass your static friction, additional force doesn't do much good.

The motor alone isn't the only thing that adds cost to a brushless motor. Teams would then need to buy addition speed controllers (though usually in the same ballpark as jaguars and victors) for their new non-KoP motors.

What voltage is the motor you linked to designed to run at? The one I found was designed for 10.5 and put out comparable numbers to a CIM, although was significantly more expensive.

Re: Why Hasn't first gone Brushless?
 

here is a similar question.

why hasnt FIRST used 12v 18Ah lipo batteries?

Re: Why Hasn't first gone Brushless?
 

Fire = bad

-Greg

Re: Why Hasn't first gone Brushless?
 

Please direct me to some 12V 18Ah LiFePO4 batteries that aren't cost prohibitive. Note our discharge rates!

Re: Why Hasn't first gone Brushless?
 

i noticed someone mention that they would to like to see stepper motors before brushless motors. it was my understanding that brushless motors were just stepper motors with fewer steps, could someone enlighten me if i am wrong

Re: Why Hasn't first gone Brushless?
 

indeed (:

id like said batteries too, ive been looking for some cheaper-than-an-arm-and-a-leg lipo batteries too ):

Re: Why Hasn't first gone Brushless?
 

Yes stepper motors are very closely related to Brushless motors, Both use digital current switching over brushes and commutator. Without the brushes, there is nothing that can wear out in a brushless motor also.


For those who dont know what a brushless(non outrunner) motor is, here is a really breif look at them. In the Layest(new word?) of layman's terms a brushless motor is a brushed motor flipped inside-out. the windings usually found on a brushed motor's armature are replaced by a permanent magnet in the brushless motor. Windings(stator) in a brushless motor are bonded to the inside of the motor can.

Since the current switching of Brushless motors is handled by the speed controller, the commutator, brushes and all associated components arent used in them.. the only moving part is the rotor. Brushless motors are 99% maintenece free.


A note on efficiency from an Industry Leader, Castle Creations

Re: Why Hasn't first gone Brushless?
 

yea ithink i would say cost too because brushless is a lot
and frist is a non profit ..

Re: Why Hasn't first gone Brushless?
 

Ben,
All things being considered, the brushed motors are the best choice for our competition. Maintenance free is not a problem for this competition since the service life is measured in hours not months. Not one team I am aware of has ever failed a motor due to brush wear or bad bearings other than those over stressed by bad design. Controllers for brushless motors tend to be more complex and vary with the design of the motor, i.e. how many poles/phases need to be controlled. Brushless motors have a bad tendency to lag under heavy loads. Brushless motors tend to be better for fixed applications like fans, video recorder head wheels and other applications that require some sort of phase lock or rotation lock. Stepper motors can be a better choice for some of our applications but again controllers become very complex. All of these motors reguire some form of feedback to operate and change speed and so control then lies outside the ability of most rookies and those teams with few mentors. IMHO, brushed motors and speed controllers still give us the most level playing field and are the easiest to implement for the majority of teams.

Re: Why Hasn't first gone Brushless?
 

as a owner of over $2000 of brushless motors, i dont think its a good idea for a few reasons

1. Need to pay MUCH more attention to gearing/heat/ etc. 90% of brushlesss motors need to be kept at about 45k RPM. Close monitoring of motor and ESC temperatures must be read and translated.

2. Cost. Yes there are $30 brushless motors, but those tend to have magnet separation. the FIEGO XL is a $60 motor but IMHO the only motor worth it is the NEU series motors at $300 each! Either way, MUCH more expensive. The economy is not in good shape, FIRST needs to stay afloat!

Lipo batteries ARE THE WAY TO GO!!! I run 12s setups giving more that 48V of power and iv never had a problem....but that dosnt mean someone that dosent know what they are doing wont catch one on fire because they didn't read the instructions...:ahh:
NOT TO MENTION the cost of a LIPO charger?! Mine costs $270....and people have to learn how to use em, balancer taps are a mysterious thing for anyone who have never used em:o

Basically im saying YES it would be AWESOME if first went LIPO and BRUSHLESS, but it dosent make sense right now:)

Re: Why Hasn't first gone Brushless?
 

Stepper motors would be SWEET. Position control without having to install yet another encoder and write yet another PID loop?

Sign me up.

Re: Why Hasn't first gone Brushless?
 

Andrew,
LIPO batteries will catch fire in the hands of teams who regularly damage the AGM cells we currently use. Fire on the field is not something I want to be a part of.
Jared,
Stepping motors and feedback are not mutually exclusive. You have to know where you are in order to control where you want to be.