Old 883= 24V Speed controller???

[stealth13777]

We are working on building a cart to move our robot around. It will be powered, and we found some 24V motors off an old robot for a different competition that we can use, but we don't have any speed controllers. On the Innovation First website the old victor 883 is listed as a 24v model. Could it be that the old 883's could handle 24V and that is why first switched to the 12V 884's? Just wondering if anyone knows whether or not the victor 883 speed controllers supplied in previous years can handle 24V. Thanks

[ahecht]

It's been a while, so I may be wrong on this, but I seem to remember that IFI made both 12V and 24V 883s (and FIRST teams were supplied with 12V 883s, since FIRST has never used 24V systems). The difference between the 883 and the 884 had something to do with deadbands.

EDIT: Okay, I looked it up, and I was partially correct. The 883 can take between 6V and 30V, but the fan on top of the FIRST models could only take 12V. However, if you use two, you can wire the fans in series. The 884 has a greater dynamic range (3%-100% as opposed to 10% to 100%), and an added deadband to compensate.

EDIT: Read SandDrag's comments below. I may have been looking at the wrong datasheet.

[santosh]

Thank you so much. You just saved us about $300 on the cart.

[alphastryk]

hmm...it looks like we can even buy 24v fans from them from IFI for $8.95. i wonder if those would actually work with the 12v fan versions...

[stealth13777]

Yeah, those fans would work, and they are what we are buying. I guess the fans were the way FIRST used to try to make sure those things ran at 12V.

[sanddrag]

I'm not so sure. I wouldn't go hooking up 24V unless you get an answer from someone at IFI who knows exactly what you have and what it's specs are I remember there were two separate websites and possibly separate divisions of the company. There was IFI Robotics which served the combat robot community and there was Innovation FIRST which served FRC. I believe there were two different Victor 883s as well. This page seems to show that the FRC Victor 883s are not suitable for 24V use. this datasheet seems to confirm that. (Oh how wonderful the almighty Wayback Machine is) Additionally, these FRC Victor 883s are only rated for 30A continuous where the combat ones are rated for 60A continuous.

Now, it is possible that IFI/Innovation FIRST is lying and they are actually both the same 24V 60A model because they didn't want combat builders to get special pricing for FIRST so they tell us ours is 12V 30A, but I think it is more likely that they are indeed different units with different specifications.

Note: the 24V Victor 883 can be seen here on the old IFIRobotics website and note that the 12V one linked to above is on the old InnovationFIRST website.

So, Do not run your Victor 883s at 24V, at least not until we find out for sure.

Also, Here's an alternative to 24V victors which is a bit cheaper (but it has no case or fan). It is two speed controls in one and can work on 4-36V and handle 50A continuous (per motor).

[Tom Bottiglieri]

I'd say try it, and if blows up... Oh well.

[sanddrag]

Originally Posted by Tom Bottiglieri

I'd say try it, and if blows up... Oh well.

You probably typed your post before you saw my above post but Don't try it! Those Victors are only rated for 15V max.

[ahecht]

Hmm, the info on the 30V stuff was from a spec sheet filed away with other documents I have from the 2002 season, but looking through the CD archives it seems that they were wrong (or perhaps for the wrong version of the 883). This thread seems to explain things a bit, while this thread leaves things somwhat in the air.

Incidently, Sanddrag, your first link goes to info on the 884, not the 883. This is probably the link you meant.

[Gdeaver]

Would the 24 volt motor have acceptable power at 12 volts?

[sanddrag]

Originally Posted by Gdeaver

Would the 24 volt motor have acceptable power at 12 volts?

What motor is it? You can get some dyno results for some NPC motors at both 12V and 24V here http://robotcombat.com/marketplace_gearmotors.html

[Gdeaver]

I've watched some motorized carts. They're not really practical at a First event. The massive hoards of humanity limit their use. A cart needs to be very maneuverable. I was thinking- if you took a couple of those moving air mats that contractors use to move refrigerators and converted the blower to 12 volts you could have a hover cart. Much better for weaving your way forward when your late for a match.

[sanddrag]

Originally Posted by Gdeaver

I've watched some motorized carts. They're not really practical at a First event.

Maybe not at a regional but at the Championship where there is a long walk between pits and field I could imagine they would be very useful.

[santosh]

We actually have a refridgerator on it and a computer (they do have a very needed use). Ok guys. The motors that we are going to use according to GT cant really do much at 12 volts. I myself wanted it to be run at 12volts when we found that the Speed controllers for 24 volt motors were $150 a piece. These motors are very powerfull and stall at like 2500lbs. and they draw something like 115 Amps when they are stalled. Yeah, hover craft cart. If only there was money enough for it. lol

We would try it and if it blew up oh well, but the CircuitRunners don't have much money to throw around.lol

We really do need this powered cart. We not only use our carts for competition, but anytime there is an outreach, there is a robot, and there is a car. So, we need the cart there too. And sometimes we have to go hundreds of yards to get to the presenting area from the place we are allowed to park our trailer. We had to pull our robots from our ending point of our July 4th parade to our booth which was like 1.5 miles away. That wasn't incredible fun.

We will probably contact IFI if nobody here knows for sure.
Also this cart is being mde completely by us the students, and all the money is going to be raised by us the students becasue school funds cant be accesed till school starts on august 9th.

[Gdeaver]

It's probably much cheaper to by new motors than new victors. On Ebay there are a couple of guys selling several replacement winch motors. Last year I got a couple for my son to mess with. I paid $13 each plus 5 shipping. There are about equal to 1.75 CIM motors and they are of a design that lends it's self to continuous use. Only problem is most of the motors are - frame ground.