View Full Version : Victor 884
Kevin Ray
26-01-2003, 16:58
Does anyone know what the major difference is between the 883 and 884 Victor. We now have a box of "useless" 883's and have to buy four more 884's at $115 each. This recent revelation is really putting a damper on things and would be more palatable if the difference was truly necessary.
Curtis Williams
26-01-2003, 17:04
I thought i saw somewhere that the 883s had a deadspot where you had to apply a certain amount of power before they would actually kick in.
Jim Meyer
26-01-2003, 17:21
Here's an ASCII of what I think the difference is in PWM width vs. requested counts:
883
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| \ /
| \ /
| \ /
| |__|
884
|\ /
| \ /
| \ /
| \ /
| \ /
| \__/
Basically, I think both have a dead spot with the 884 having a smoother transition from the dead spot to an active state.
HolyMasamune
26-01-2003, 18:11
I think I read somewhere that you can only use 884s for this year's competition, not sure but you might want to check the manual or something.
The Victor 884s are capable of up to 40 amps, rather than 30 amps, and they also have a power range of 3%-100% rather than 10%-100%.
According to Innovation First, this should mean better (more precise) arm control.
Kevin, is your team interested in selling your old 883's?
No, we just think its unfair to not let us use them for the motors that dont require 40 amps, some of us are personally paying for parts out of pocket due to lack of funds, and just having these lay around and not be able to use them is bad. We dont like the idea that we are forced to buy more from innovationfirst even though they are not a safety hazard and will work just as well. I begin to wounder what the exact pourpose of that rule was trying to accomplish, as far as I can see - only to force us to buy new things we already have just so they can make more $$$
Duke 13370
26-01-2003, 19:33
No, we just think its unfair to not let us use them for the motors that dont require 40 amps, some of us are personally paying for parts out of pocket due to lack of funds, and just having these lay around and not be able to use them is bad. We dont like the idea that we are forced to buy more from innovationfirst even though they are not a safety hazard and will work just as well. I begin to wounder what the exact pourpose of that rule was trying to accomplish, as far as I can see - only to force us to buy new things we already have just so they can make more $$$ I agree completly, we have about 6, 883's just lying about and can't use them. It's rather frustraing:(
Jeremy_Mc
26-01-2003, 19:44
hooray for rookie teams who don't have old parts :)
i wish i could help you guys out. the best thing i can tell you is put 'em on ebay...battlebots people eat those things up. you'll atleast make a little money back...
*jeremy
bigqueue
26-01-2003, 22:16
I can think if several reasons for the ruling.
1) It makes it easier for judges. They con't have to INSPECT to make sure you have a particular speed controller n a particular motor on a particular fuse.
2) Its called leveling the playng field. It will keep older teams from having such an advantage over rookie teams.
3) Then there is of course safety....probably the big reason. Another 30% current is not insignificant....(though safety also goes along with reason #1)
-Quentin
Originally posted by RebAl
No, we just think its unfair to not let us use them for the motors that dont require 40 amps, some of us are personally paying for parts out of pocket due to lack of funds, and just having these lay around and not be able to use them is bad. We dont like the idea that we are forced to buy more from innovationfirst even though they are not a safety hazard and will work just as well. I begin to wounder what the exact pourpose of that rule was trying to accomplish, as far as I can see - only to force us to buy new things we already have just so they can make more $$$
Curtis Williams
26-01-2003, 22:42
What would it matter about inspecting it? The current limit on the 883s is lower. It would actually be safer. It wouldnt really matter about what breaker you put upstream from it. No need to inspect. There was no extra inspection when a team used 884s instead of 883s last year.
Allowing would level the playing field because teams with less money could afford to have more speed controllers or hold them as backups.
Originally posted by bigqueue
I can think if several reasons for the ruling.
1) It makes it easier for judges. They con't have to INSPECT to make sure you have a particular speed controller n a particular motor on a particular fuse.
2) Its called leveling the playng field. It will keep older teams from having such an advantage over rookie teams.
3) Then there is of course safety....probably the big reason. Another 30% current is not insignificant....(though safety also goes along with reason #1)
-Quentin
1) The electrical system should have all the wires traced anyway to make sure it is the proper gauage for the motor and fuse used, and the maxi breakers are hard wired anyway so finding their attatched victors shouldent pose a problem, just in the same way they must trace a relay to a motor to make sure it is legal
2) It would be less of an advantage because it does not have the same current and it does not allow you to use all of the power as mentioned above, only advantage would be not having to pay $$ but at the same time having a old victor
3)If the victors are attatched to the correct fuses there is no safety hazard
Also what if a team bought 5 victors from years before, are they useless just because they dont have the same features that first feels we need? I guess our team will have to cut down spending in other places, like for the nats because of this extra 650+ expence.
Joe Johnson
26-01-2003, 22:52
I can think of 2 more reasons to get rid of the 883's
The 883's came in 2 flavors "red" and "blue" The older ones (can't recall which was which) required an external transorber to suppress transients to the rest of the wiring harness. Perhaps they just got tired of having to explain to inspectors when to look for external transorbers and when not to?
A more serious issue may involve electro-magnetic compatibility.
The 883's had a PWM frequency of something like 1000 Hz (perhaps more, again, memory fades...). Victors use something more like 100 Hz.
I am only a mechanical engineer, but I think that the following two things are true about this change in frequency:
#1, Your motors will start to move at lower duty cycles at 100Hz than and 1000Hz (in effect, the motor's time constant acts like a filter that filters 1000 Hz more effectively than 100 Hz)
#2 1000 Hz will act more like a radio station than 100 Hz
It is my understanding that Innovation First is working on new radio system for their EduRobotics that they are looking to migrate to their FIRST product.
Lower EMC problems may be an important factor in making the switch.
Finally, Innovation First may just be tired of supporting the older product. If this is the price of keeping Innovation First in the business of making control systems for FIRST, it is well worth it. As an 8 year veteran, I can say without hesitation that we are much better off with Innovation First than without them.
In any case, it is a hardship, but it is not an undue one (imho) especially since we have the K3 rule limiting how crazy we can get with extra Victors anyway.
Just my 2 cents.
Joe J.
D.J. Fluck
26-01-2003, 23:14
Put the 883's on ebay. They should sell for at least 50 dollars a pop. Ive heard that there was a team once that did that and they got back 60-65% of the value of them from the auction. Have the winner pay shipping and you could make back a nice sum of money
On EBAY I found a set of Victor 883's for $175 for a set of 2....they do sell. (The guy put BATTLEBOTS in the title, but whatever sells them)
BSMFIRST
27-01-2003, 02:53
>>On EBAY I found a set of Victor 883's for $175 for a set of >>2....they do sell. (The guy put BATTLEBOTS in the title, but >>whatever sells them)
Those were probably not the 883's you guys have laying around.
Check out http://www.ifirobotics.com . That's the non-FIRST (ie BattleBots) side of Innovation First. They have a 24V Victor 883 that is rated at 60A.
You're right though, the BattleBots folks will buy the old 12V 883's--the lower weight classes robots (30, 12, 2 and even 1 lb) are getting popular.
Dan
sanddrag
27-01-2003, 02:58
Try eBay in the RC car section. People pay way too much money for speed controls in there.
Kevin Ray
27-01-2003, 09:22
Thanks to all for your insightful responses. Although no ONE answer seems to be enough to justify forcing all teams to stop using the 883's, collectively, the arguments make it easier to agree with their decision.
Now, just keep your fingers crossed that we won't have 885's next year!
Al Skierkiewicz
27-01-2003, 14:14
All in all the 884 is such a big improvement over the 883 it warrants the change. But there is other factors to consider...
Innovation FIRST has always been very helpful in replacing suspect components, helping research problems and truly listening to their customers, US. The 884 is a direct response to those requests in that it is a higher current, less deadband, more fine control version of their previous products. If you were at a competition this year, had used an 883 with the expected deadband and ran into a problem you thought was a speed controller, would you want to just drop in an 884 and hope it would be OK or would you want to get an exact replacement device?
Joe Johnson hinted that the output signal was about 1000Hz, and I found a data sheet from a few years back that stated it was 2000Hz for the '00 883. Although I have not seen any discussion on this subject (and would welcome that from a knowledgeable source) I would expect an interaction between frequency of switching, brush/commutator length, motor speed and ultimately accuracy of control. The 884 is theoretically attempting to optimize all of these factors and give us higher current outputs.
Thats all good but what if we dont need all of those things? Why are they forcing us to use 40 amp victors on 30 amp breakers (we can't even get the full usage of the 40 amps if we can only use 30 amp fuses), it makes no sence to me that we cant have something worse then other teams have if we want to, there is no unfairness to that besides the fact that these victors that we need to buy now might keep us from going to the nats just because now the playing field is unleveled between us and those with large sponsors that can afford more.
-no saftey risk
-poorer operation
.....how could that be unfair to other teams if we used them??
Jeff Waegelin
28-01-2003, 09:30
We do get 40A fuses this year, though.
While we do get 40 amp fuses, we only get four.
My team is using an 8 motor drive train, with 2 other non drive motors. Only 4 of those acutaly are able to take advantage of the 884's higher current rating (which I think is a silly idea anyways, but thats another post). So here we are, forced to buy at least 6 more of these things that are over rated and completly unnessecary. Its a huge chunk of our budget that we are forced to give up.
If FIRST wanted to get rid of 883's, fine, but wouldn't it be better for all of us if they were phased out? This year for instence, only 884's could be used on the 40 amp motors, with 883s being legal on all the others. Next year, move the FP up to a 40 amp breaker (which it should be on anyways) and so on, untill teams have had the chance to spread the cost of new 884's over a few years.
Frankly, I've been nothing but happy with the 883's. I've never had a problem with one frying because of to much current (and our 02 bot was a current monster), and I've always found them to be plenty accurate.
-Andy A.
bigqueue
28-01-2003, 13:12
Originally posted by Andy A.
While we do get 40 amp fuses, we only get four.
My team is using an 8 motor drive train, with 2 other non drive motors. Only 4 of those acutaly are able to take advantage of the 884's higher current rating (which I think is a silly idea anyways, but thats another post). So here we are, forced to buy at least 6 more of these things that are over rated and completly unnessecary. Its a huge chunk of our budget that we are forced to give up.
If FIRST wanted to get rid of 883's, fine, but wouldn't it be better for all of us if they were phased out? This year for instence, only 884's could be used on the 40 amp motors, with 883s being legal on all the others. Next year, move the FP up to a 40 amp breaker (which it should be on anyways) and so on, untill teams have had the chance to spread the cost of new 884's over a few years.
Frankly, I've been nothing but happy with the 883's. I've never had a problem with one frying because of to much current (and our 02 bot was a current monster), and I've always found them to be plenty accurate.
-Andy A.
I don't fully understand your post. If you are adding motor controllers that were not in the kit, you would have to post that charge against the cost of the robot anyways....no?
I'm not saying you would not have a REAL savings because you would be taking them from last years robot...but that fact does not change the fact that you would have to account for them in tne $3500.
Did I miss a point in there?
BTW: Last year was the Phase out year...there were both 883 and 884s in existance. Yes, only 883s came in the kits, but 884s were available to purchase. Had you bought the 884s last year, you could have used them this year. (but I think you would still have to "account" for the cost of any parts not provided in the kit either way)
-Quentin
Sorry, when I said budget, I was refering to the team budget, not the robot budget. Yes, we would have still account for the cost of the speed controllers against the $3500. That had already been assumed. But, we are now spending money we had hoped to use to offset the cost of nationals and other non robot costs. Had 883s be legal, we would still have 600+ in the team budget to spend on getting us to Texas.
I know I am just $@#$@#$@#$@#$@#ing at this point, but this is just one of those things that just annoys me to no end. We had thought that 884's had been offered last year as an alternative to 883's for fine arm control type aplications. Since we had nothing like that, we just stuck with 883's. I still curse that choice.
Was any annoucement made last year that 883's would be illegal this year? If one was, I'm going to kick my self silly...
-Andy A.
Lewis Sussman
28-01-2003, 14:27
Originally posted by Andy A.
Was any annoucement made last year that 883's would be illegal this year? If one was, I'm going to kick my self silly...
-Andy A.
Andy, if there was such an announcement I'll do the kicking ;-)
But seriously, in my mind a "phase out" would be an announcement that says "both 883s and 884s are available this year, but next year 883s won't be allowed, so buy accordingly." We bought 883s last year expecting them to be spares for this year, and now we're holding the bag... My recollection, having ordered them last year is that we were given the choice based on functionality but not warned about the rule change for this year.
Joe Ross
28-01-2003, 14:43
Originally posted by Andy A.
Was any annoucement made last year that 883's would be illegal this year? If one was, I'm going to kick my self silly...
Team update 1 deletes all references to the victor 883s from the manual. Since they are clearly electronic parts, and they can't be purchased from digikey or FAI (and even if they could, they would cost more then $100 each), they are illegal.
As for references to the FIRST forum: http://jive.ilearning.com/thread.jsp?forum=3&thread=541&message=1055&q=383833#1055 http://jive.ilearning.com/thread.jsp?forum=3&thread=1305&message=3156&q=383833#3156 and http://jive.ilearning.com/thread.jsp?forum=5&thread=489&message=956&q=383833#956
Errr... I know FIRST has made them (883's) illegal this year and made a point of making that clear. That was never in question.
What I wanted to know was last year (the 2002 season and off season) was any annoucement made by anyone, FIRST or otherwise, that this would be the case for 2003? It seems that the answer is no, so I don't feel like a complete idiot.
When did IF annouce they were stopping production on the 883?
-Andy A.
Joe Ross
28-01-2003, 15:02
Originally posted by Andy A.
Errr... I know FIRST has made them (883's) illegal this year and made a point of making that clear. That was never in question.
What I wanted to know was last year (the 2002 season and off season) was any annoucement made by anyone, FIRST or otherwise, that this would be the case for 2003? It seems that the answer is no, so I don't feel like a complete idiot.
When did IF annouce they were stopping production on the 883?
Sorry, I misunderstood.
It wasn't announced that the victor 883's would be illegal till team update one. According to Innovation FIRST's news page (http://www.innovationfirst.com/firstrobotics/news.htm), it wasn't announced that the 883s were discontinued till December 23 of last year. So, no, you were not the only one blindsided.
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