Removable link
andy the pugh
Mentorn that our robot will require a "removable link without which the
robvot will not run"
Has anybody any idea what is meant by this phrase? Does it have to be
external? Easily pulled out without tools? Or can we just unbolt a
battery wire?
--
ap
Greg Middleton
No Andy, you need something you can pull out from the outside of the bot
and hold up to 'flag' the fact that it's disabled. The motorsport
battery cut off keys are very popular, industrial fuse holders with
shorting links fitted have also been suggested.
Greg
Dan The Man
going into the same plastic socket which go into the plug, when pulled out
it cuts the power. These are easier to pull out then small and award keys.
Dan
------
"Greg Middleton" <gr...@nospam-deepseaplc.com> wrote in message
news:396E3B7C...@nospam-deepseaplc.com...
andy the pugh
> > I am informed by the chap who gets all the information sent to him from
> > Mentorn that our robot will require a "removable link without which the
> > robvot will not run"
> No Andy, you need something you can pull out from the outside of the bot
> and hold up to 'flag' the fact that it's disabled. The motorsport
> battery cut off keys are very popular,
Yes, but, the robot can still run with the key out, if the case is
squashed, for example.
I have such a switch in our robot, but the key is captive. I am going to
have to redesign things to conform to the rule that the key should be
removable, something I would prefer not to do so late in the day.
I have a neat, armoured, toggle on the top armour that operates the
keyswitch through a coupling, I am going to have to scrap the whole
thing, probably.
Why couldn't they get the new rules to us a little sooner? Like when we
_start_ building?
--
ap
Greg Middleton
>
> Why couldn't they get the new rules to us a little sooner? Like when we
> _start_ building?
It seems to be beyond their organisational skills, it's been the same
for every series 8-(.
Greg
Gary Pike
their web site you need one of those aircraft/lorry pullout fuses.
We are hopefully getting one this weekend, but life would be so much easier
if we simply changed our existing cut off switch for one where the key came
out.
Gary
"Greg Middleton" <gr...@nospam-deepseaplc.com> wrote in message
news:396E3B7C...@nospam-deepseaplc.com...
> andy the pugh wrote:
> >
> > I am informed by the chap who gets all the information sent to him from
> > Mentorn that our robot will require a "removable link without which the
> > robvot will not run"
> >
> > Has anybody any idea what is meant by this phrase? Does it have to be
> > external? Easily pulled out without tools? Or can we just unbolt a
> > battery wire?
>
> No Andy, you need something you can pull out from the outside of the bot
> and hold up to 'flag' the fact that it's disabled. The motorsport
nozza
<ga...@bug-bits.freeserve.co.uk.nospam> wrote:
>Greg, are the auto cut off switches allowed. The way the tech spec reads on
>their web site you need one of those aircraft/lorry pullout fuses.
>We are hopefully getting one this weekend, but life would be so much easier
>if we simply changed our existing cut off switch for one where the key came
>out.
>
Who knows?
The rules sent out said either a "red flag"key type, or a removable
fuse, the online rules said removeable link, and now, the sheets with
the bios that arrived a day or two ago say "must have a removable
link". You'd think they'd have got their act together by now. Then
again, if they ran a proper safety check, and a proper Tx control
system, plus if the arena crew knew their place, things would be a lot
quicker, and a lot safer.
Example
We are now told that "for safety reasons" all switches have to be
together". That means that if we wanted to use our external RC switch,
we'd have to move it round to the area of the power switch. I don't
see why. It's not as if the arena crew (for whom we are told such
changes are for - for their safety) should NOT touch or operate the
robot at all, except under the direct direction of the roboteer, if
the arena safety officer (who should have some training in safety,
preferably a diploma from Aston/Herriott Watt) determins it's unsafe
otherwise.
In fact, with a proper safety check, and a proper Tx control, and
arena screening, such things as tethers would be un-needed. After all,
there's been no injuries in the US caused by runaway bots in the years
of competition since '94.
Perhaps the lack of suitable knowledge is the reason it takes Mentorn
so long to do each match (timed by Arthur Chilcott to average 30
minutes) as opposed to BattleBots (timed, again by Arthur Chilcott, to
average 5 minutes). The last BattleBots was by far the slowest,
comming in at around 7 minutes per match, but that included waiting
for the nnouncer and the smoke machines, as well as the impromptu
arena repairs, yest it still got 4 weight classes done in 16 hours of
events.
I look forward, with intrest, to seeing how long the croud manages to
stay, before becomeing bored and leaving, at the "Robot Mayhem" event.
Greg Middleton
<ga...@bug-bits.freeserve.co.uk.nospam> wrote:
>Greg, are the auto cut off switches allowed. The way the tech spec reads on
>their web site you need one of those aircraft/lorry pullout fuses.
>We are hopefully getting one this weekend, but life would be so much easier
>if we simply changed our existing cut off switch for one where the key came
>out.
>
>Gary
Sorry for the late reply, just got back.
As I, and others, understand it the autosport type switches are
allowed, if not there are going to be a lot of very upset people
turning up and being disqualified. But of course this is Mentorn ...
What I can say for sure is that they are allowed in the NARC
construction rules, along with any other device that achieves the same
objective.
Greg
Adam Clark
about suitability of links etc. Mail me if you don't have their phone
numbers.
Gary Pike wrote:
>
> Greg, are the auto cut off switches allowed. The way the tech spec reads on
> their web site you need one of those aircraft/lorry pullout fuses.
> We are hopefully getting one this weekend, but life would be so much easier
> if we simply changed our existing cut off switch for one where the key came
> out.
>
> Gary
>
> "Greg Middleton" <gr...@nospam-deepseaplc.com> wrote in message
> news:396E3B7C...@nospam-deepseaplc.com...
> > andy the pugh wrote:
> > >
> > > I am informed by the chap who gets all the information sent to him from
> > > Mentorn that our robot will require a "removable link without which the
> > > robvot will not run"
> > >
> > > Has anybody any idea what is meant by this phrase? Does it have to be
> > > external? Easily pulled out without tools? Or can we just unbolt a
> > > battery wire?
> >
> > No Andy, you need something you can pull out from the outside of the bot
> > and hold up to 'flag' the fact that it's disabled. The motorsport
> > battery cut off keys are very popular, industrial fuse holders with
> > shorting links fitted have also been suggested.
> >
> > Greg
--
Dangerous Machines : http://www.dangerousmachines.com/
Get Steel : http://www.wlcooke.co.uk
Gary Pike
3/4 turn to remove and then the battery is completely isolated. Of course a
cheap motorsport one would be easier, but if they get funny about it, as you
say, a lot of people will be upset.
Gary
"Greg Middleton" <gr...@nospam-deepseaplc.com> wrote in message
news:3975649b.4510305@gateway...
> On Fri, 14 Jul 2000 08:03:29 +0100, "Gary Pike"
> <ga...@bug-bits.freeserve.co.uk.nospam> wrote:
>
> >Greg, are the auto cut off switches allowed. The way the tech spec reads
on
> >their web site you need one of those aircraft/lorry pullout fuses.
> >We are hopefully getting one this weekend, but life would be so much
easier
> >if we simply changed our existing cut off switch for one where the key
came
> >out.
> >
> >Gary
>
Greg Middleton
<ga...@bug-bits.freeserve.co.uk.nospam> wrote:
> Of course a cheap motorsport one would be easier, but if they get funny about it, as you
>say, a lot of people will be upset.
Well they've got funny about it 8-(, they're telling everyone at the
auditions (call them what you will) that the auto sport switches are
not allowed, but they're allowing them to compete anyway as most
people are turning up with them !.
They say they won't be allowed during the actual contest, hmm, so
they're safe enough for most of the battles but not for all. They say
you must have a removable link, i.e. the piece that comes off is part
of the circuit, and that slave relays aren't allowed, the link must
break the actual power.
Potential entrants may also like to know that they are telling people
the FS1 type failsafes are not recomended, but are being allowed !,
again they don't seem to be able to make up their mind about safety.
Unfortunately they don't seem to know what IS recommended either. The
only thing that seems certain is that failsafes are being properly
tested (for the first time by most accounts) and many have had
problems passing this test, so be prepared.
From initial reports the organisation seems to be as bad as ever, and
the rules just as flexible when it suits THEM 8-(.
Greg
nigel.paget
Our robot Knightmare qualified with the 300A key isolator from Maplin.
We got told to replace it for the main TV event.
We did this and installed a 60 A (60 amps at 240VAC) fuse carrier.
We got to the heat final against Spawn and after an head-on collision our
fuse carrier became dislodged.
We would have won this otherwise and would have got to the semi's.
(I know any body could have said this if you look at the first melee we had
with Spawn you will see we could have beat him.)
Thats the game and we accept our defeat, but down to robot failure not a
fair fight in our eyes.
Anyway, the thing that makes it worse is that other robots on the TV event
still had their key isolators and we had obeyed the rules.
Nigel (team Knightmare captain.)
Greg Middleton <gr...@nospam-deepseaplc.com> wrote in message
news:397ff35b.4501422@gateway...
andy the pugh
> We did this and installed a 60 A (60 amps at 240VAC) fuse carrier.
Which sounds a bit lightweight, really, as the current is all that
matters.
> We got to the heat final against Spawn and after an head-on collision our
> fuse carrier became dislodged.
Bad luck, I suspect that there might have been quite a lot of that with
the new rules. The rule makes sense, it would have been nice to have had
more than a weeks notice though.
FWIW our removable link was a 9mm brass rod which slid through two
aligned cylindrical contacts in a block af nylon. I modified some big
MilSpec connectors, but a sufficently effective arrangement could
probably be fashioned from a couple of split bits of tube.
The advantage with this sort of arangement is that the rod has to be
pulled out at least 2" to break the circuit.
--
ap
Greg Middleton
>
> Regarding Removable links.
>
> Our robot Knightmare qualified with the 300A key isolator from Maplin.
> We got told to replace it for the main TV event.
> fuse carrier became dislodged.
I'm sorry to hear you got knocked out this way but I'm not the least bit
surprised how it happened. Fuse carriers were not designed to be used as
switches, let alone on a vehicle experiencing severe G forces, and
clearly can simply fall out.
At least that failure mechanism is 'fail safe', the other worrying
failure mechanism when you misuse these (and one I've come across
professionally) is that the contacts can weld because they're just not
designed to switch current. That's 'fail to danger' i.e. you can't stop
a runaway, and I suspect it's only a matter of time before this happens
too.
Unfortunately Mentorn just don't seem to have a clue, forcing people to
replace a purpose designed and properly rated safety component with
something not designed or rated for the job was quite simply negligent,
if an injury had resulted from this action they would have been in real
trouble.
Incidentally you mention 60A at 240VAC, but remember that the fuse
holder is still only rated at 60A even at low voltage DC and this is
just not up to the job for most heavy weights. Stick the hundreds of
amps that some bots intermittently draw through the these contacts and
it could weld in situ 8-(.
Greg
Gary Pike
triangular axe bearing machine. Our whiskers got caught around the wire
loop and as we went backwards we pulled it out.
We used an aircraft recharging link that has a half turn screw fit and will
handle at least 500 amps. Matt actually liked it although suggested it was
rather overkill, and told us we needed a simple plug in connector.
Like everyone has said, the old key switches worked well before. The only
problem is you can't easily see if they have been switched off. Like a
mains powered machine, if you pull the plug out, you know it is powered
down.
Derek had a bag with the part in that they recommend, still in their RS
bags. I suggested to Rick my team mate to go with Derek to get the numbers
written down. Derek told Rick (who didn't know the numbers were on the
bags) that he didn't have them to hand and he would see him later. Of
course he never did and the ease at which getting the numbers would have
been was lost. So any help Mentorn could have been to ensure we had the
correct parts went with it.
This is one of the things I don't understand, they make a suggestion/new
rule, but are unwilling to state exactly what they want. Although I'm sure
it isn't easy for those of you in the UK, but here in Guernsey we are the
only Roboteers and have no one to discuss ideas with face to face, plus we
don't get to RW events due to the 300 pound trip every time. Anyway, we're
designing for RW5 now and hopefully will begin construction of the
championship winning machine in the next few weeks.
I'm sorry to break it to you like this, but we have already won RW5, in our
heads. :-)
BTW, did the sheep get through to the show this year?
Gary
"nigel.paget" <nigel...@ntlworld.com> wrote in message
news:VEhn5.21519$Lv6.2...@news2-win.server.ntlworld.com...
> Regarding Removable links.
>
> Our robot Knightmare qualified with the 300A key isolator from Maplin.
> We got told to replace it for the main TV event.
> We did this and installed a 60 A (60 amps at 240VAC) fuse carrier.
> We got to the heat final against Spawn and after an head-on collision our
> fuse carrier became dislodged.
nospam
connectors to me, http://www.andersonpower.com/ a 350A version available but
we borrowed their 175A set from the mangler. Did the job.
Jonathan Barnes
"Greg Middleton" wrote
> At least that failure mechanism is 'fail safe', the other worrying
> failure mechanism when you misuse these (and one I've come across
> professionally) is that the contacts can weld because they're just not
> designed to switch current. That's 'fail to danger'
> Incidentally you mention 60A at 240VAC, but remember that the fuse
> holder is still only rated at 60A even at low voltage DC
I believe AC fuse holders need to be de rated for DC use so It's worse than
just the amp limit.
--
Regards
Jonathan.
To reply please remove additions.
Barnes's theorem: For any fool-proof device there
exists a fool greater than the proof
Greg Middleton
>
> "Greg Middleton" wrote
>
> > At least that failure mechanism is 'fail safe', the other worrying
> > failure mechanism when you misuse these (and one I've come across
> > professionally) is that the contacts can weld because they're just not
> > designed to switch current. That's 'fail to danger'
>
> > holder is still only rated at 60A even at low voltage DC
>
> just the amp limit.
I suspect you're confusing fuse ratings with fuse holder ratings. The
rating of a holder is purely a function of the heating caused by the
current, remember the holder is not designed to break a circuit so it
matters not if you're dealing with AC or DC, and if the insulation can
handle 240V it can also handle 36V. Fuses on the other hand are designed
to break a circuit and breaking DC is much more difficult than AC of
course.
Greg