14-10-2012, 12:57 PM
Ok, in order....
There is nothing wrong with the operation of either the teddington or the relay, both work correctly as designed. The contacts inside the teddington arc when they break, driven by a decrease in temp by the sensor (capilliary tube containing methanol/water mix driving against a bellows in the teddington). The guys on the mainline who have bottomless pockets just stick a new one in when the one fitted gives up the ghost, I don't have that sort of bottomless pockets in the order of a couple of hundred pounds as a starting price and I really want to fix this on a prevention basis. They just live with the knowledge that they are going to be replacing units on a regular basis, totally rediculous and wasteful. We were looking at treating the coil as if it was an old car spark coil with condenser and points, snubbing the back emf to earth by fitting the cap across the coil but a diode or diodes in series across the coil with diode negative to earth looks a possibility.
There is nothing wrong with the operation of either the teddington or the relay, both work correctly as designed. The contacts inside the teddington arc when they break, driven by a decrease in temp by the sensor (capilliary tube containing methanol/water mix driving against a bellows in the teddington). The guys on the mainline who have bottomless pockets just stick a new one in when the one fitted gives up the ghost, I don't have that sort of bottomless pockets in the order of a couple of hundred pounds as a starting price and I really want to fix this on a prevention basis. They just live with the knowledge that they are going to be replacing units on a regular basis, totally rediculous and wasteful. We were looking at treating the coil as if it was an old car spark coil with condenser and points, snubbing the back emf to earth by fitting the cap across the coil but a diode or diodes in series across the coil with diode negative to earth looks a possibility.
