11-07-2024, 11:56 PM
I came across similar relays, used (why?) to switch input power to a Westinghouse 3-phase transformer-rectifier unit supplying DC to cinema arc lamps. The high-current path was kept local, and the low-current switching was beside the projectors.
There would appear to be no advantage in mercury relays - the control cabinet even had a couple of spare relays, so they were not considered faultless by design. The number of switching operations was three per hour (for 20-minute reels), hardly massive... However, it did introduce me to a bit of new technology!
Unfortunately the rectifiers themselves, despite dating from 1936, were not MAR's but metal (whether copper-oxide or selenium, I never found out!)
There would appear to be no advantage in mercury relays - the control cabinet even had a couple of spare relays, so they were not considered faultless by design. The number of switching operations was three per hour (for 20-minute reels), hardly massive... However, it did introduce me to a bit of new technology!
Unfortunately the rectifiers themselves, despite dating from 1936, were not MAR's but metal (whether copper-oxide or selenium, I never found out!)
