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Speed controler info
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Spockie-Tech
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Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia


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Well, if I was trying to make a living out of selling controllers, I might be more biased.. Wink,

but as I'm sure verybody knows by now, I reckon if you take into account the time I spend helping people with IBC's I would have been far better off just sticking to my day job.. (Good thing Jason handles all the production and stuff or the IBC wouldnt exist)

This is a hobby for me, not a business, so at the end of the day I just want to see everyone have fun, which is why I try to be open-minded about using any controllers that work for you..
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Post Wed May 04, 2005 3:45 pm 
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Knightrous
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Joined: 15 Jun 2004
Posts: 8511
Location: NSW


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You're a rare thing to find in this sport Brett Smile

I'll back the IBC because I use it and have had no real problems that wasn't my fault. But having seen what the Kerison guys have done with there victors, I'll back them any day too (Except for the lack of heat sinks Very Happy ).

I was talking to Andrew today and he's kicking me into making him some relay switches for his lifter bot, so I'm also looking at ordering the parts for my PicAxe PWM Controllers too. So when they are complete, I'll let everyone know how good/bad they are and if they are a possible solution of cheapness with out the suffering from low performance.

Current costs are around $50 per controller right now, which should be able to handle 50amps or more. (using 3 fets on the half bridge and 70amp/60amp relay reversing). I'll be putting the source code online soon and possibly some wiring diagrams or some PCB designs for people to look at.
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Post Wed May 04, 2005 4:12 pm 
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Glen
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looks like the sidewinder has gone up to $399 US. OUCH
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Post Thu Jul 21, 2005 6:05 pm 
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dyrodium
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Joined: 24 Aug 2004
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Location: Sydney


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Hi, just a question about the IBC, what motors can it run? Like, what have people used with success and what caused it to stuggle? Could it run 200w scooter motors with fan cooling or is that too much? Smile
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Post Thu Jul 21, 2005 10:01 pm 
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timmeh
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Joined: 20 Jul 2004
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George from team nexus runs 250watt scooter motors off an ibc in king pinscher his light weight and i dont think hes had a problem with that setup.


He has blown his ibc before but from what i can make out its from tinkering around with different batterys and fuses and staling and such but youd have to ask him when he gets on.
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Post Thu Jul 21, 2005 10:05 pm 
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Knightrous
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I reckon you could run 4 x 300watt scooter motors before you'd even start warming the IBC up.

We run 340watt winch motors in T2M and they draw a good 100+amps when you sitting on it driving around on it like a NarKart. Also, Tim 's robot KO ran 4 x 12v drills @ 24v and didn't burn it out. He got it warm, but never cooked it.
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Post Thu Jul 21, 2005 10:07 pm 
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Nexus
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Tend to agree with Aaron. Kingpin also has a ratio of 3:33 so it really puts a strain on the batteries and motors and the IBC has handled that up to 28.8 volts.
Keep in mind also that gear ratios can make a big difference in how much amps you use. You might be able to avoid stall currents with enough torque on the wheels.
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Post Thu Jul 21, 2005 11:05 pm 
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Spockie-Tech
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About the only thing that people have tried to do with an IBC that has blown them up with any regularity is 4 x drill motors at 24v and then stalling them..

Even 4 x drills at 12v is iffy if you stall them badly. George is correct, your amps are most significantly affected by your gearing.

If you look at some of the American "torque/power" calculators, the secret is to have your wheels break traction just before the motors reach maximum torque. Not only is this kind to your ESC, but if prevents the batteries, motor windings and wiring for the motors from frying.

You can run 4x24v drills if you're careful not to stall them (SS Rat does), Scooters are no problem. What else did you have in mind ?

Not only the ESC, but many parts of a combat bot are not over-rated enough to handle a sustained stall. To be competitive we have to run too close the edge for that sort of safety margin. If you arent on the edge, you're taking up too much weight.. Smile
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Post Fri Jul 22, 2005 12:09 am 
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Spockie-Tech
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Location: Melbourne, Australia


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BTW some temporary IBC news..,

Jason has suddenly had to travel overseas for 4 weeks for some urgent work-related jobs, so all IBC sales and reapirs are on hold until he gets back..

I hope this doesnt inconvenience anyone too much.. I have to figure out why Scoopy's Arm IBC died at Round 3. no blowups, frm what I can tell so far, it just seems to be a brain-failure (microprocessor).

Hopefully I can find a spare around here somewhere or I'll be waiting in line when he gets back too.. Rolling Eyes
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Post Fri Jul 22, 2005 12:16 am 
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kkeerroo
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Joined: 17 Jun 2004
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quote:
Originally posted by Spockie-Tech:
Not only the ESC, but many parts of a combat bot are not over-rated enough to handle a sustained stall. To be competitive we have to run too close the edge for that sort of safety margin. If you arent on the edge, you're taking up too much weight.. Smile


What kind design method is that? You should design everything (or choose componants) that can handle everything and/or anything that can possibly ever happen to it. I think that an esc should be able to run a stalled motor continously without any problems or consider another design.
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Post Fri Jul 22, 2005 12:40 pm 
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dyrodium
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I was wondering about running 2 300w scooter motors. Smile
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Post Fri Jul 22, 2005 1:55 pm 
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colin



Joined: 16 Jun 2004
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quote:
Originally posted by kkeerroo:
quote:
Originally posted by Spockie-Tech:
Not only the ESC, but many parts of a combat bot are not over-rated enough to handle a sustained stall. To be competitive we have to run too close the edge for that sort of safety margin. If you arent on the edge, you're taking up too much weight.. Smile


What kind design method is that? You should design everything (or choose componants) that can handle everything and/or anything that can possibly ever happen to it. I think that an esc should be able to run a stalled motor continously without any problems or consider another design.


When you crash a car, it doesn't handle it, you can't drive it anymore. And crashing falls well within "everything or anything" that could happen to a car. I'm not sure what your trying to say here...

Post Fri Jul 22, 2005 5:42 pm 
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kkeerroo
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A car is designed to just move people and to be cheap. Not repeatedly crashed into things like a robot should be.

If you choose a speedo and motor combo where you know that if the motors stall the speedo will blow but design the drive train so the motors won't stall under normal use then you havn't designed your robot correctly. If, for expample, Evil Spike puts its spike thought your wheel and jams the drive train, like what happened to Hellbringer X, then you can kiss you speedo good bye. If the spike is removed your robot is still dead. However we went over kill on the speedos, the motors stalled and the IFI took it for the full 20 seconds (Andrew's a hardcore driver, eg 3 drills in 10 seconds at RWII) and when the spike was removed the robot was still able to keep fighting and it won the match.

This is what we mean by designing to take anything and everything.
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Post Fri Jul 22, 2005 6:27 pm 
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Spockie-Tech
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Location: Melbourne, Australia


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Everything is a compromise in engineering.. I'm sure you guys know that.

I can make an indestrutible speed controller no problem. make it indestructible, light, cheap, and small ? No can do. same with a bot.

Over-engineering something in a limited class is wasting resources that could be used for something else.

A bit of overkill on the ESC's isnt a bad thing, since they tend to be the most expensive thing to repair if they do get overloaded, so leaving a little safety margin there is a good idea, but the IBC handles 95% of the jobs its asked to do without any problems, so I think it has plenty of headroom for its intended applications.

Its a lot easier to try and make sure your wheels slip before the motors stall than fit an indestructibe controller.. Wink thats how the overall package should be designed.
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Post Fri Jul 22, 2005 6:56 pm 
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Ali



Joined: 06 Mar 2005
Posts: 92
Location: Scotland


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Im going to run my rambot with 4 x 18v drills @ 24v using the IBC . Hearing that i could blow the IBC if i stall the motors is a bit of a worry , I have a huge 80mm Vantec tornado fan that im going to put over the IBC's heatsink , would that be OK ?
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Post Fri Jul 22, 2005 10:04 pm 
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