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John Olsen24/09/2010 00:08:55
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I was at Canterbury university in 1980, they were doing work on AC motor controls then, and I did a project in that area. They had just built an electric car as a test bed. The motor contol part worked fine, but then, the motor control part has never really been the problem with electric cars. Even with 1905 style technology, you can get quite respectably high efficiency out of the electricity to mechanical part of the conversion. The real problem has always been the weight of the necessary battery pack and of course its cost. The lithium cells have helped there, but there is still a way to go I think.
 
Most of the types of inverters likely to be used for DC to three phase conversion inherently have diodes between each output and the DC rails, either for protection or because they are inherent in the devices. This means that such devices will generally inherently provide regenerative braking. The Canterbury car was set up that way, the first bit of travel on the brake pedal slowed down the AC frequency to give nicely proportional braking from the motor, but when you pressed harder it started working the hydraulic brakes. With half a ton or so of batteries in a mini size vehicle, you sometimes needed that. It also had a built in limited slip differential. There was a motor for each (front) driving wheel, both driven off the same controller. To a limited extent, one motor could go faster than the other, eg around corners. However, if one motor started to slip, eg on wet grass, it would only slip up to syncronous speed at most, and the other motor would continue to drive.  Quite nice, if only we could find a battery with the same energy density as a tank full of petrol.
 
Of course , the inverter back then that took a box the size of a computer case will now almost fit in my pocket. 
 
regards
John
Andrew Johnston24/09/2010 09:17:35
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John S,
 
Makes sense, even dreaming spires need maintenance, unlike perspiring dreams.
 
Andrew
Richard Parsons24/09/2010 13:17:50
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Sam’l  you comment why no profile? Model Engineers are a lonely secretive lot. We go to our workshops (the place which SWMBO calls our ‘play room’ and stay there with luck for hours. The dog might visit us occasionally, but it usually leaves when something goes wrong.  It does not like the language which would make the hairs on the head of a Billingsgate fish porter stand on end. My shop has many cobwebs in it my SWABBO is afraid of spiders. Nuff said!

My only public appearances are at the Supermarket (for portering and payment duties) and at the local Kocsma (a place where you can get delicious liquid refreshments from barrels and brown bottles).

John -So it was you who left those confounded bricks there.  I nearly fell over the damned things leaving the Angle and Greyhound one night on my way to visit the Port Mahon! (Yes they are both real inn signs).

Edited By Richard Parsons on 24/09/2010 13:18:38

Stub Mandrel24/09/2010 19:42:05
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John S, so that's why they call them red-brick universities!
 
Beware what you put in your profile - the SO might find out what you spend all the hard-earned on.
 
I have been an enthusiastic CFL user for years. Our house is cursed by three-socket fittinmgs meant for three 40W canlde bulbs. as much use as a chocolate fireguard. We have three 100W-equivalent CFLs in each one - much better!
 
Neil
Andrew Johnston24/09/2010 22:50:17
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Oh dear Neil, that's a real faux pas! Even though Oxford University does have some red brick buildings and sad to say the engineering department is white tile.
 
But here's a little puzzle; Oxford and Cambridge are the two oldest collegiate universities in the UK, but which is the third oldest? Hint; it's a proper red-brick university.
 
Oh, and I don't need to worry about the SO either; the dining room is the tool and measurement equipment store, the kitchen is for castings and parts for the traction engines and the entrance hall is for work in progress.
 
Regards,
 
Andrew
Andrew Johnston24/09/2010 22:56:57
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Hi Sid,
 
I must admit that Canada is on the short list of countries I would like to visit. A friend of mine from Cambridge has just upp'd sticks and moved to Vancouver, to become technical director of a power electronics company there. It was a no holds barred move, he's sold the house here, and taken the wife, kids, and the machine tools, but I don't know about the dog.
 
He did offer me some work a few months ago, but I had to turn it down because I was too busy on other projects. In due course I hope there'll be some more work available, so I can visit Vancouver and BC, and get paid for it.
 
Regards,
 
Andrew
Gone Away24/09/2010 23:19:09
829 forum posts
1 photos
Hi Andrew,
 
That's about the same as I did, something over 40 years ago with £500 in my pocket . Of course I was just 25 then (most unlike me really). At that time it was pretty easy to walk into a job if you had decent qualifications (I had nothing arranged prior to coming here).
 
Canada's been pretty good for me and I don't regret it for a minute but I must admit to a slight hankering, now that I'm retired, to moving back to some small out of the way place in Cornwall or Devon or Dorset. (I have relations ^H^H^H^H^H^H relatives in Cornwall). Too many ties here now though.
 
One downside: living here does mean that you pay more than anyone else in the world for MEW. Gaddafi and the Ayatollah can get it cheaper than Canadians.
 

Edited By Sid Herbage on 24/09/2010 23:23:49

Ian S C25/09/2010 09:41:33
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Andrew, did they name it after you (3rd oldest uni). Got a cousin in Vancouver the rest of the familys' visited him , I'm waiting for him to come here. Perhaps he can't escape. Ian S C
Richard Parsons25/09/2010 11:11:28
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One of my ‘long fathers’ went to Canada, or rather he was sent to Canada by his sons (as a remittance man) after his wife, their mother, died. It seems to have been because of his new hobby which was, by all accounts, molesting young ladies. He seems to have persisted with this hobby in Canada and got paid to move further and further West where (on Vancouver Island) he was forced to re-married and begat a new family. Some years later history repeated its self and he was sent to New Zealand (again on remittance) where in his old age he had to marry again – The grounds for divorce was that the shot guns (in Canada) were not properly loaded-. There the dirty old devil seems to have begat another tribe in the ‘Land of the Long White Cloud’.
 
Sid - My tribe got 'hodded out' of Dorset many hundred years ago for 'Gross Evil'.  (this probably had somethig to do with either molesting young ladies or for flogging seawater as top of the range smuggeled brandy.

Edited By Richard Parsons on 25/09/2010 11:20:02

Andrew Johnston25/09/2010 11:11:31
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Hi Ian,
 
No, it's not named after me! I agree that St. Andrews is the third oldest university in the UK, but it's not the third oldest collegiate university in the UK.
 
Regards,
 
Andrew
 
Andrew Johnston25/09/2010 11:24:54
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7061 forum posts
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Hi Sid,
 
Funny that you should mention that MEW costs the earth in Canada. I mentioned to my friend in Vancouver that I'd just had an article published in MEW, and he bemoaned the fact that he'd need a second mortgage to buy a copy locally.
 
I wonder why it is so expensive in Canada, and how does it compare with US prices?
 
Regards,
 
Andrew
Gone Away25/09/2010 15:07:31
829 forum posts
1 photos
Hi Andrew,
 
I was really referring to the subscription price. The US subscription price is a bit less than than the Canadian - which is odd considering that they're both serviced out of Montreal.
David Clark 125/09/2010 15:19:59
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3357 forum posts
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10 articles
Hi There
Canada hs a purchase tax on magazines.
I think it was mentioned it is 11%.
regards David
 
Gone Away25/09/2010 15:35:08
829 forum posts
1 photos
.... it's 13% but it's calculated separately not buried in the price. That is, the quoted prices (the ones I was commenting on) are exclusive of tax and are still $10 more than ROW.
David Clark 125/09/2010 16:41:38
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3357 forum posts
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10 articles
Hi Sid
As far as I am aware the canadian price includes Tax.
Unless you can prove differently.
Then I can queery it.
I keep asking them to change the subscription advert to read ROW except USA and Canada.
It keeps falling on deaf ears.
At best it is misleading, at worst, it looks like fraud but is unintentionally so.
regards David
Gone Away25/09/2010 17:11:59
829 forum posts
1 photos
 Hi David
 
OK, I went to the ExpressMag website. The price is CDN$99 (no mention of tax). Added it to the shopping basket and went to checkout. It says:
 
Subtotal $99 before taxes
 
 so:
 
UK price £44.50
ROW (e.g. Iran) £52.95
US (US$89)  ~ £56
Canada (CDN$99) ~ £62
 
BTW, on the subscription page, there are separate buttons for UK, US, Canada and ROW which is quite clear to me. I don't think it's misleading as you suggest. The US and Canada buttons flip you through to ExpressMag.
David Clark 125/09/2010 19:32:49
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3357 forum posts
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10 articles
Hi There
I was going by subscription prices in magazine.
regards David
 
Gone Away25/09/2010 20:35:59
829 forum posts
1 photos
You mean the fact that it doesn't make it clear that the ROW price does not include Canada and the US?
 
Yes, now that I look in the mag I can see what you mean about misleading.
Stub Mandrel25/09/2010 20:47:46
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4318 forum posts
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Andrew,
 
I went to the oldest college in the country - Aberystwyth. Oh! you're talking about England! Probably Durham then?
 
Neil
NEIL SMITH 126/09/2010 02:47:31
26 forum posts
ROW don't need a middleman,why do we?
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