A major player in the EVSE market has kindly consented to provide some technical training for the electrical installation tutors at a training centre where I often tutor part-time. I imagine it is not entirely motivated by altruistic considerations but at least it gives an opportunity for the tutors and myself to get some kind of grasp on the various products on offer and where this particular manufacturer sees the direction of travel for EVSE. I am already aware that the company is moving away from products that rely on the installation of earth electrodes in PME situations and are placing considerable focus on load management. Is there any particular question that you would ask them given the opportunity?
Ok Andy, you seem to think that total disconnection if the mains goes 20V down on normal indicates a broken CNE. It may, but may not. You can disconnect everything but disconnecting the Earth connection requires all manner of saftey systems to be safe, a single contactor doesn't do it at all. Remember that Earth connection needs to be disconnected in <40ms, just like an RCD. Any fault will disconnect and reconection cannot be automatic, can it? The fail would be all the time, not even occasionally with a real mains supply. A half-cycle at nearly zero volts is remarkably common and causes no trouble to anything except you mains disconnection idea. The problem is you do not have the time to wait, as waiting could kill someone!
As far as cars go, I currently have a Ford thing with a stop-start engine and extra-low emission on loan. OK it works, but a new battery every couple of years is likely and the cost of one is £££. If I stop and the battery packs up I cannot move, again looney. On an older car, as long as I can do one start I can go as far as I like and the miles per gallon are very nearly as good as my much bigger diesel. Electric cars are good in jams as found in Bristol where I have ther misfortune to live. They are designed into the road system at every opportunity, because of "climate change" and the Council wishes to drive vehicles off the road and everyone to use public transport (including building a tube network at an incredible cost in a hard rock, hilly area). B**** brilliant. I wish I could think of ideas like that, on some immense salary, but unfortunately, I can understand why they are stupid and impossible, which is because I am an Engineer not a politician with an agenda.
Ok Andy, you seem to think that total disconnection if the mains goes 20V down on normal indicates a broken CNE. It may, but may not. You can disconnect everything but disconnecting the Earth connection requires all manner of saftey systems to be safe, a single contactor doesn't do it at all. Remember that Earth connection needs to be disconnected in <40ms, just like an RCD. Any fault will disconnect and reconection cannot be automatic, can it? The fail would be all the time, not even occasionally with a real mains supply. A half-cycle at nearly zero volts is remarkably common and causes no trouble to anything except you mains disconnection idea. The problem is you do not have the time to wait, as waiting could kill someone!
As far as cars go, I currently have a Ford thing with a stop-start engine and extra-low emission on loan. OK it works, but a new battery every couple of years is likely and the cost of one is £££. If I stop and the battery packs up I cannot move, again looney. On an older car, as long as I can do one start I can go as far as I like and the miles per gallon are very nearly as good as my much bigger diesel. Electric cars are good in jams as found in Bristol where I have ther misfortune to live. They are designed into the road system at every opportunity, because of "climate change" and the Council wishes to drive vehicles off the road and everyone to use public transport (including building a tube network at an incredible cost in a hard rock, hilly area). B**** brilliant. I wish I could think of ideas like that, on some immense salary, but unfortunately, I can understand why they are stupid and impossible, which is because I am an Engineer not a politician with an agenda.
