Forget Bluetooth, even 2.4GHz devices often don't work due to local interference! Just came across a 2.4GHz phone which put a lovely interference bar up on a 2.4GHz video/tv link. I think it's the base station paging to find out if the phone is still there!
Regards Capitol
What is the fixation with kitchens? My house has one ring that includes the kitchen. Like I said ring mains are not very well designed.
I can assure you that a two part portable AC works fine even if it does draw
3kW.
I meet with VCs on a regular basis whilst working with startups and governmental agencies and have seen this regularly all through 2003/4/5. Before 1999 it was of course a lot more speculative of course, and of course was fairly dead in my field through to early 2003 apart from some IPOs.
There were a large number of WiFi startups but I'm not aware of any that got full funding until the standards were fixed. Bluetooth was a little vaguer as the technical document was at first presumed to be solid and investments were made before the errors were found. It turned out that the people who could solve those problems fastest, like CSR, got the business.
For all future startups expect the seed and S1 funding to be available to many but the main tranche of funding needed to fab the IC not to be made available until the standard is fixed.
$30m for a startup. Have advised on four this yeara and one of the biggest hurdles is convincing them this is the minimum they will need - most seem to think they can manage on $8-10m. Even certain government agencies struggle to get their head round this. But nobody is going to commit this sort of money without a standard.
Totally agree. But this is having an impact on the more traditional standards bodies and they are speeding up. 3G was defined far faster than GSM for example despite being far more complicated. We are also seeing things like UMA defined outside the standards environment then presented as a 'done-deal' only at a higher quality level than Bluetooth was. I expect this sort of thing to multiply.
But as you say startups don't compete in the main arena but on the edges and it is often possible for them, with assistance from a BT, Alcatel or whoever, to get their IP in a standard. Alternatively the people on the startup work for one of these big players and only set up shop once they are sure the standard is ready.
I bet your post went over more ATM links that it did packetised links to get to me. Of course the information was stored in packetised form whilst traversing the ATM network but these packets were not looked at apart from at the ISP servers, the BT exchange routers and our PCs. I think ATM will be around for some time yet.
There are private networks and bypass technologies of course, but the bulk of transport is still leased links, voice and Internet traffic and the bulk of all of these use BT's network - which is predominently ATM based.
Yeah right, only a 60%+ difference in the answer ;-)
Do me a sausage...
Lets say we have a load with a nominal impedance of 8 ohms. That would be 7.2kW dissipation assuming zero voltage drop in the supply cables. In reality less obviously.
So lets say we have 30m of 2.5mm T&E cable in the ring at a nominal resistance of say 15 mOhm/m (R1 + R2), that 0.45 ohms in total.
So that is 8.45 ohms load total, or 28.4A
Double your cable resistance and you get a current reduction to 27.0A, a
5% reduction in the total current flow (and total power dissipation)In the above example it drops it to a sustainable current for a single bit of 2.5mm^2 T&E clipped direct or in plaster...
Hmmm...
Hmmm...
Does it have thermal mass? Thought so....
Clutching at straws perhaps...?
Depends on your insulation. Could be 0.1 for a cavity wall filled with insulation.
One of the factors you include in your circuit design is the type of insulation surrounding the cable. If you feel that you are getting close to the limits then you specify either a heavier cable, or one with a thermosetting insulation, or simply one sheathed with a material having a higher k value (XLPE or LS0H cables for example).
The Euro-plug. No other plug could be legally shipped within the EU on any appliance. Adapters would have to be used but people would be encouraged to gradually change their wall sockets as needed.
As it would become the IEE 'n'th edition, it would be in fact the only current standard. Do you still wire things to 15th edition for example ? However that standard would have to make recommendations on the best way to make modifications to existing systems and that may well be to extend rings as we do now, but with the new socket. Conversely it could decree that all new wiring must be on new radials to the full Euro standard. Not for me to guess what the IEE would decide.
Which to me is a big advantage. But you think otherwise. We are never going to agree on this one so I think it's time to let it rest.
Obviously the EU has more weighty matters on it's plate at the moment but if and when these are solved harmonisation of a whole raft of things will be back on the agenda - transport and electrical systems amongst them.
Most countries don't want their existing systems kept so no. But I expect any standard would have at least the UK, German and Swedish systems in addendas. However this is for existing systems, not new installs.
An interesting point - will it be cheaper for us to install electric boilers or electric room heaters ?
They are typically the area in a house with the highest concentration of high power consumption devices. Hence why they are sensibly wired with their own ring circuit.
No, you mean *your* ring main is not very well designed. The last one I installed is fine thanks.
So that's why cars use less and less material with every new model?
As the electrical distribution system world wide, uses ring connections for local areas and also uses diversity to minimise the costs of transformer installations, I'm prepared to accept that rings are a "good thing" and that "Diversity works". Perhaps I'm just naive!
Regards Capitol
ps, does remind somewhat me of IMM logic however. n combi's?
Obviously there often is blackening at old joints but I have been surprised at how many blackened points you see at some point in the middle of a cable run. Of course one only sees this once the cable has been pulled out so it is hard to tie down why it might have happened.
Not intending to prolong the pain too much further, but what advantages can you see in said harmonisation? I can see one or two from the OEMs point of view (i.e. only having one mains lead type to worry about), but they seem pretty minor. Have I missed something?
Electric heat pump aircon I would have thought. With the recovery of "free" heat from outside you bring the cost down to that approaching gas.
Not even a power tool ? I typically replace one a month and I'm not using them anything like as much as a professional might.
Sorry but that is exactly what was suggested - hence the proposal for using localised mini-CUs such as those already in use in Italian commercial premises. It could also eventually would allow remote control and monitoring of every appliance as well but that isn't the prime reason.
I dont think so, but if you can provide a link... AIUI they say its not
16th edn compliant when used for that, which is a different thing. Any proper understanding of rings has to start by grasping the difference between ratings that include safety margins, regs, and what a cable can really carry. They are necessarily not the same things.they are.
thats entirely illogical
Smaller yes, but certainly not insignificant. Theres an entire industry of manufacture, wholesaling and retailing thats making a nice living out of the cost of materials.
NT
Seriously?
I Don't recall ever needing to replace a fuse on a power tool. I had to replace one once on a 5 amp extension lead which got upset with prolonged use of a 6 amp chainsaw, but that was 20 years ago!
My point was that it's unrealistic for a VC to expect a start-up prior to funding to have the resources to drive a standard for their technology. This may be conservative UK VC behaviour, but is not typical in the US.
You're talking about the semiconductor industry. Obviously for that, it would be reasonable for a standard to exist prior to major funding.
However, this is a special case because of the huge investment required for fabrication.
It is not typical in the rest of the networking industry.
Obviously, but you are speaking of the semi industry, and that is not typical outside it.
Again, this relates to the telecomms and semi industry. My point was that the issue of a standard being *required* to receive VC funding is not generically true and is more specific to the sector with which you are familiar. Outside of that, it is more typical to do something that either doesn't require a standard or which makes use of existing ones without being hampered by them.
While I can appreciate the importance of having standards set in advance for semiconductors which are a) expensive in the setup phase and b) expensive to change; it is not generically true and a blanket application would kill off innovation. Added to this, VCs are notoriously impatient for a return. The majority simply won't hang around waiting for the likes of international standards organisations to dick around producing camels.
Really? When did they chuck out all the SDH?
The goal of all harmonisation is that at sometime in the future we are all following the same rules and use the same products throughout Europe.
Look at the nonsense when you visit mainland Europe now. Changing the UK to driving on the right isn't an option (and in fact driving on the left will soon be in the majority worldwide so it could be argued that it is actually continental Europe who would have to change) but it would be useful to have the same rules - not 'prioritie a droite', different speed limits, do you park with handbrake on or off, is taping the car in front normal or not, etc. Then at the hotel - mains adapter plugs, modem adaptor plugs and so forth.
If you want to see positive examples of harmonisation consider the Euro, your GSM phone and the English language. All work almost everywhere - the latter even in Paris :-)
The alternative is of course that in 100 years we are still where we are now. It works but it's nowhere near perfect.
And concerning your point about OEMs, you should see how many different wall-warts many companies have on their master parts lists. They really are a logistical nightmare and shipments arriving at local distributers with the wrong one in the boxes is far too common to be funny anymore.
I'm sure it did, but these days, as Stefek I think said, they are in the form of point to point links hooking together IP infrastructure. In that sense, the concept of a packetised link becomes pretty much irrelevant in the sense that the link can be ATM, POS, .....
The latest game in this series is MPLS. My prediction for that is that it will go the way of the others within 10 years.
I'm sure it will, but it is relegated to creating low level links between layer 3 IP infrastructure and never achieved more than a tiny fraction of the multi-service potential that was claimed it would do.
At one point the proponents were claiming that it would replace Ethernet as a generic connectivity medium, even to the desktop. I can think of only a very small number of organisations that adopted it for this purpose, and most long since threw it out because a) it was expensive, b) it didn't work properly, c) test equipment was poor and expensive and d) expertise was in short supply.
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