| |
You are here: Experts > Home/Garden > Home Improvement/Repair > Electrical Wiring in the Home > 1930's school clock
Expert: Greg Hughes - 11/3/2009
Question
I have a 1930's school clock. It has 3 wires. Black, White, Red. The lable says 24 VDC. Does that mean that you need to supply 24 VDC to the three wires or does it have something internal to convert AC to DC. How would I connect 24 VDC to the three wires. I would like to see if the clock will still work.
Answer
How the schools kept all the clocks running at the same time, which is very important when you have all those classrooms, is they used a low voltage "master clock controller".
The master clock controller sent a pulse ever minute to one of those wires that advanced the minute hand. After 59 minutes the master clock controller sent a pulse to another wire that advanced the hour hand.
Therefore; one wire is the ground, one wire is for the minute hand, and one wire is for the hour hand.
Without a master clock controller your clock will not work. Even though it is 12vdc it requires a pulse, not a steady voltage, to operate it.
My guess is that if you apply house voltage or 12vdc you could damage the circuitry.
If you really want to restore it you will need to take the brand name and look up "master clock controller" for that brand and model.
But since you only have one clock and nothing to sync it with I don't know if it worth doing that or not.
Add to this Answer Ask a Question
|
|
