The Siren Board

I understand that the later Thunderbolt RCM controls were designated RCM1A for three phase power and RCM1B for single phase power. My question is concerning the earlier Thunderbolt controls designated TC-4, TC-7, TC-7C and TC-7D. All of these designations are stamped into the serial number section of the data plate. It isn't a serial numbering system as I have seen the same designations on other control enclosures. Does anyone have any idea what the different TC designations are for?

I've got a lot of tbolts also that are TC-7D. I have no clue what it means. It's stamped on every tag on the siren.



picture credit goes to DJ226

My ID tag looks similar except it doesn't have any letter after the "T."

My thunderbolt ID Tags are similar... I guess it stands for "Thunderbolt"?

The TC designations are specific to the controls only. These individual designations are on the control enclosure wiring schematics for the panel only. I have the schematics for the TC-7, TC-7C and the TC-7D. I don't have them for the TC-4, but I know I've seen that designation on a control enclosure.

Some of my tbolts have TC-7D on the blower frame tag and the head tag.