N/o - N/c Having Trouble

alan i thought you could remember when panels still had valves in them ?

(hands in membership of round table and honery rsty tin of ovaltine)

lol!

well at least you know what valves are,

the first panels i worked on used ex GPO very large relays, later i worked on rely-a-bell panels, same relay's but using mechanical interlock, i think brocks and afa amongst others also used the same basic design.

meant on a pm you had to clean the 'open to air' springs with a piece of note paper, adjustment was with pin nosed pliers to the latch. door contacts were brass kerry clip's on the frame and a bar attached to the door, had to be cleaned with emery cloth - no fancy dan electronics back then - pah!

the 1000ft monoptic rays were mains driven, bigger than a 8mm projector - no standby or backup, used a synchronous turntable motor (from a gramophone) to run a fan with slots in to give modulation from a car headlamp bulb, the receiver had valve's .

very often we bounced the beam around a warehouse using several if not a dozen mirrors at the corners, real bugger to re-align on your own if the fork lift had a little ooops', especially on high side windows. also, try to working out exactely where the sun was flooding the receiver causing fasle alarms in that situation

most 'service engineers' in here don't know your born by comparison, you knew you had a 'arrived' when the firm gave you a swing needle meter - without a crack glass

regs

alan