New Speed Controllers :)

[Pavan Dave]

Do you think we will get Victor 885's in the Kit next year?
click here to see 885


OOooh soo excited. Already have half an OI built on Photoshop


-Pavan

[rufu5]

120A continuous? Pretty wicked Maybe we will get them with the new RC I have been hearing so much about

[Richard Wallace]

Originally Posted by rufu5

120A continuous? Pretty wicked

Maybe you'll at last be able to drive the magic smoke out of that CIM! 120A continuous current from the 885 is more than sufficient to stall the CIM long enough to destroy it.

To use more current, we'd need bigger motors. Bigger motors increase robot power and also mechanical stresses, thus requiring more strength (and therefore more weight) in the mechanisms that use them. And of course more powerful robots would require a more robust field to contain them.

I think the robots are wearing out the carpet, field boundaries, field elements, and game pieces fast enough as things stand now -- more power is not needed.

More (robot) intelligence is.

[Pavan Dave]

Originally Posted by Richard

Maybe you'll at last be able to drive the magic smoke out of that CIM! 120A continuous current from the 885 is more than sufficient to stall the CIM long enough to destroy it.

To use more current, we'd need bigger motors. Bigger motors increase robot power and also mechanical stresses, thus requiring more strength (and therefore more weight) in the mechanisms that use them. And of course more powerful robots would require a more robust field to contain them.

I think the robots are wearing out the carpet, field boundaries, field elements, and game pieces fast enough as things stand now -- more power is not needed.

More (robot) intelligence is.

Lol.. I beg to differ my frined. I believe there rae ways you can strenghten the field and you can double lay the carpet or use other equally good fabric or something for the carpet and they can give us 10 lbs on the bot ?? Lol

We can dream cant we?

Pavan

[Adam Richards]

Originally Posted by Pavan

Lol.. I beg to differ my frined. I believe there rae ways you can strenghten the field and you can double lay the carpet or use other equally good fabric or something for the carpet and they can give us 10 lbs on the bot ?? Lol

We can dream cant we?

Pavan

I think it would likely take more than 10lbs for most teams if much stronger motors were added.

Though it would probably be very fun, I doubt it would be safe to drive around 250lb metal beasts at 30fps in a FIRST game...

[Alan Anderson]

The Victor 885 is intended for 24 volt applications.

[Richard Wallace]

Originally Posted by Alan Anderson

The Victor 885 is intended for 24 volt applications.

Originally Posted by Victor 885 Speed Controller Specifications

Control Signal Standard R/C Type PWM (Pulse Width Modulation)
Operating Voltage 6V to 30V (does not include the fan)
Fan Type Rotron. Battle proven by Inertia Labs (and many others).
12V Fan Voltage 6V to 16V
24V Fan Voltage 16V to 30V
Maximum Current 120A continuous
Surge Current 200A for < 2 second
300A for < 1 second
Power Connector 6-32 Screw Terminals
Signal Connector Use a standard non-shrouded PWM cable (3 wires)
Typical Application Power one motor with variable speed forward, reverse, or off
Weight 0.25 lbs

Seems like you could use it at 12V since it's rated for operation at 6V.

Anyway, as long as we're using 40A snap action breakers on each circuit, the capability of the 885 won't be exploited. We'd get a small benefit in reduced voltage drop. For FRC use that doesn't seem worth the difference in price.

885s seem to be intended for big bots. 24V x 120A is 2880 Watts; at about 75% efficiency that would be about 3 HP at the motor shaft. Way too much power for a FIRST robot, even if we were to get motors that could handle it.

[Gdeaver]

They cost to much. I would rather see some programmability in the speed controllers. Like current limiting, current feedback and protection circuitry. Also maybe a small cheaper ESC for the window motors and van door motor. International rectifier has allot of new automotive stuff with some reference designs that could be Incorporated into First robot motor control. If we had intelligent speed controllers, the 2005 Fisher Price motor problem could have been solved at the speed controller. While servo pwm has worked well, maybe its time to think about going to a motor control bust or something.

[d.courtney]

who says we are even going to have carpet next year (my vote(and hopes) is on water... )

[Rohith Surampudi]

Originally Posted by d.courtney

who says we are even going to have carpet next year (my vote(and hopes) is on water... )

there could be wet carpet...or a pool and for some reason it would have carpet on its floor

[Pavan Dave]

Originally Posted by Richard

Seems like you could use it at 12V since it's rated for operation at 6V.

Anyway, as long as we're using 40A snap action breakers on each circuit, the capability of the 885 won't be exploited. We'd get a small benefit in reduced voltage drop. For FRC use that doesn't seem worth the difference in price.

885s seem to be intended for big bots. 24V x 120A is 2880 Watts; at about 75% efficiency that would be about 3 HP at the motor shaft. Way too much power for a FIRST robot, even if we were to get motors that could handle it.

Yep. Your absolutely correct. There is no way that we need that much power on the field unless FIRST was taking a turn for the worst turing it into BattleBots.. (Thank god its not)



Pavan

[John Gutmann]

draining 120A continously will COMPLETELY drain your battery in 9 minutes flat. SO think about it if you have 2 motors (probally drive) running around 120. you battery will completey be drained in 4.5 minutes. Not to mention everything else your running. This means (estimate only) that by the end of the match your battery would be around 6-7 volts maybe. do you really wanna drain your batteries that fast? Besides doesn't that ruin them?

[Richard Wallace]

Originally Posted by sparksandtabs

draining 120A continously will COMPLETELY drain your battery in 9 minutes flat. ...

Actually, much quicker than that.

See the battery datasheet and this thread.

[John Gutmann]

well anyway why would they let you use 120A continuously if they can just step up to the old 883's that run up to 60A continuously. I think that is more acceptable, plus you dont have to use practically a solid copper rod for a wire.

[Tom Bottiglieri]

Originally Posted by sparksandtabs

well anyway why would they let you use 120A continuously if they can just step up to the old 883's that run up to 60A continuously. I think that is more acceptable, plus you dont have to use practically a solid copper rod for a wire.

Unless you are straining 10 motors, there is no reason you should EVER get anywhere near 120A continuous current draw. Not to mention your batteries would bite the dust quite quickly with that kind of abuse.

By the way, you would be much better off using thick stranded wire than one solid piece of wire. Current flows on the surface of a conductor, so the amount of current a single piece of wire can transmit is limited by its size.