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Hi All
Im soon to be purchasing these batteries:
http://www.overlander.co.uk/detail.asp?categoryid=55&ID=92http://www.overlander.co.uk/detail.a...oryid=55&ID=92
And I wanted to ask if my 12v motors stall, and Im running them on 24v (I should be anyway), will the stall current exceed 30Amp, because thats the rating on my speedos (a pair of electronize ones)
Thanks in advance
David Weston
if need be you can allways turn them down to a lower voltage on the speedo. also i belive they have standard 30amp fuses in them so it would blow just the fuse if anything. youll probably find on 12v they are fast enough as thats what i run them on at events with the same size wheel that you use. 18v may be too quick.
30 A is the continuous rating. The Electronize controllers will handle higher short term stall currents. There is also a temperature sensor that will turn off the speedo at about 150 A.
http://www.electronize.co.uk/model_electronics_frames.htmhttp://www.electronize.co.uk/model_e...ics_frames.htm
30 amp electronize dont come with fuses James, not as standard anyway
hmm. all 3 of mine had them. and my 15amp ones. if yours dont david it would be easy to put one in.
you must be getting special treatment James
Fella on the phone at electronize said they do not come with fuses. 15A do, 30A dont. Maybe your dad put them on without you knowing? or maybe they came with them for a short time all those years ago when you started roboteering? but not anymore.
General advice to roboteers buying on other peoples advice (including mine, no offence to anyone) its cheaper to phone and ask the manufacturer than get sent the wrong thing.
any news on me getting my stuff back JC?
(Message edited by jamesb on November 25, 2005)
ps, its about £9 to fix usually if you blow one up.... your call on the fuse David.
Ye might be because i get mine direct from the factory and watched them make the speedos when i pick them up.
like i say it is easy to put a fuse holder in and is worth doing just in case.
the point I was making, as I am a retailer of electronize speed controllers (although I have to admit that I do not sit in their factory watching them build my order.... wonder how many customers they do that for?) is that, as Philip said, the controllers are capable of more than 30A. In fact, the single direction versions are rated at 40A as the relay is the component setting the 30A limit. (did you know that JC?) So, my advice, is that if you need less than 30A, it is easy to put a fuse in, but if you want to use the full potential of the controller, dont. Worst case it blows (in a fight no more deadly than the fuse blowing) and you send it back for repair. The only time I would reccommend using fuses in a combat robot is if you know the repair is more expensive, you have no spares, or as in some cases, you do not know what you are doing and get other people to wire them up for you.
so, do I get my stuff back JC? or will you send back the money I gave you for it? Just wondering... you could alway return one of the e-mails I sent you to keep the discussion off the forum...
A fuse will prevent a short circuit burning all the cabling in your robot.
James baker. Put your claws away!
David- Fuses are always important during testing:)
James, another one of your classic replys, fantastic! if i said grass is green you would post back claiming it wasnt, he he. ..hey why not put the whole story on the forum, just a thought :)
scince you changed your email address, your emails go straight to the junk mail and so get deleted. jb you have my phone number & and ive not recived 1 call dispite me trying to get through to you with no reply many times.
now lets not be plonkers and get on with the discussion in hand. I agree dave, In all cases i feel blowing a fuse is far better than blowing a speedo. just looking at the costs and convinience side of things.
Can any one give me a diagram to wire in the fuse ? I may well be upgrading to an IBC before too long, but, in any case, its useful
coming right up
Right, here it is...
http://www.micro-maul.co.uk/images/davewestoncircuit.jpghttp://www.micro-maul.co.uk/images/d...toncircuit.jpg
Ive adapted one of my existing diagrams to make it, which features a single IBC running a 4WD four motor machine but if you imagine the ibc is just two electronizes (the motors are running two per channel in the diagram so just imagine you are cutting one out of each channel for two motors/2WD).
I have put two fuse options on the diagram, each is labelled fuse block. If you dont know already, a fuse block is a small plastic plug which you can insert fuses into. You can get them and (fuses) from technobots.
The two fuse blocks down by the motors are what you really want - they are protecting the speed controller (and everything downcircuit from it) from big currents from the motors. Youll need one fuse per motor probably, in the diagram ive shown it as one per two motors (they are wired in parrallel).
The fuse block at the top only serves to protect the battery (NOTHING ELSE), you might want to put this there if you are worried about short-circuits further down the circuit from the motors. Most robots only run fuses on the motors and dont run this main one.
I should start charging for this you know :)
What happened to my beautiful circuit? :sad: lol
Ewan, nice drawing. However, the link should go into the positive side. Thats common practive.
Mike
Ah yes, my bad. Just remember that when your wiring up Dave, I havent got the time to edit the drawing right now...
All to good use AJ :)
You can also subsitute a fuse with a thermal reset switch. They commonly come in sizes ranging from 10amps to 80amps. Basically they are a slow blow bi-metallic cutout that will take 1-2 seconds of higher peak current before they cutout. Give them around 5seconds and they cut back in. Good for those situations where you stall a motor for a few seconds but still want to continue on battling :proud:
I think I should clarify my intentions with these replies.
They ARE NOT personal snipes at JC
They ARE an attempt to stop people who do not know as much as they think they know giving advice to people who are new, Ewans simple mistake of putting links in the negative line for example, something JC has done in practice on a customers robots. As I said, it is nothing personal, just making sure the newbies get the best info.
For the record, Kane makes a good point, and there is a great reason to put a fuse in. Notice nobody else came up with that in their advice. Goes to show Kane is the best person to listen to out of the people who have answered (me included)
So, anyone know how come new e-mail addresses go straight to junk mail? sounds more like a petty spite to me. maybe its just a coincidence but Ive never heard of that before.
Dont really want to discuss anything with you on the phone JC, just post the stuff Ive paid for, and the rest of my property along with the Vids I loaned you, using the money I sent you for P&P. Its been 6 months, Im sure you are busy but this is getting a bit silly. If you dont have my stuff, Ive sent the values, so send me my cash back.
Back on topic, I would suggest to Dave Weston, with no offence meant, that if you do not know how to wire in a fuse you should maybe do a little more research before building anything, or at least have a look in some live events to see how the electronics are done in the flesh.
(Message edited by jamesb on November 28, 2005)
Just for clarrification, the reason the link/ fuse is put in the positive line is that MOSFETs dont like loosing their earth path.
MOSFETs need somewhere for the energy to flow and if you remove this path, it is likely to result in their untimely death.
thanks kane.
Thanks for the diagram Ewan, much appreciated.
Mr Baker: perhaps I worded the question wrong. I am aware how to install fuses, but I wasnt certian as to the best location for them, I can see now that the way I asked the question may of sounded rather silly
hello david, no offense meant, just trying to save you a few quid in blowups or a few lost fights, depends which way you look at it.
by the way, Ive been asked by James Cooper to post to let everyone know that I have, this thursday in fact, recieved almost all of the things I was waiting for, and mentioned above. A part of the agreement of me getting it was that id post this, so true to my word,, if you could all ingnore the whole give me what I paid for 6 months ago thing, that would be nice.
there we go, everyone is friends again.
Sorry to jump in late on this discussion, but Im not quite clear on the position of the link in this circuit. I understand that speed controllers can suffer damage if they dont have anywhere to dump excess power, but Im not sure why putting the link on the positive side - directly in line with the fuses on Ewans diagram, if that is what you meant - would help matters.
A just think this: replace the 30 amp fuse to 40 amp, what happends then whit the electronize ?
i chud stand that , amp limit 90 amp and a temp sensor turn it off when it get to hot.
40a is fine, as ive said before, the limiting factor in a 30A elecronize is the relay at the moment. run in just 1 direction and 40A is not a problem, in fact I have run one at 70A spinning up a disk. it is good practice to put a link in the + side, but as kane said, it lets the fets discharge
Perhaps my A-level knowledge of physics is missing something subtle here but I thought that if the positive battery connection is isolated then no current can flow into either terminal.