30-09-2020, 08:21 PM
Hi
The changeover happened some time in the mid 1930's, possibly when the Ruby changed from ARQ to ARR but that's only my guess. Early senders have an oval cover plate and a side terminal, later ones a rounded rectangle shape and an end terminal.
Over the intervening years many senders and gauges must have been swapped of course !
I don't know of an easy way to change the sense of the sender, other than dismantling and modifying it.
One thing that goes wrong is that the end of the sender's resistance wire is earthed by simply trapping it between the outside of the insulating bush of the terminal and the hole in the mazak body (on the ones I've seen anyway). You eventually get corrosion and poor contact. Dismantle and clean to cure.
The changeover happened some time in the mid 1930's, possibly when the Ruby changed from ARQ to ARR but that's only my guess. Early senders have an oval cover plate and a side terminal, later ones a rounded rectangle shape and an end terminal.
Over the intervening years many senders and gauges must have been swapped of course !
I don't know of an easy way to change the sense of the sender, other than dismantling and modifying it.
One thing that goes wrong is that the end of the sender's resistance wire is earthed by simply trapping it between the outside of the insulating bush of the terminal and the hole in the mazak body (on the ones I've seen anyway). You eventually get corrosion and poor contact. Dismantle and clean to cure.