Standard Electric Time Master Clock Restoration Part 1

[@jeffg8232]

Hi. Thank you so much for taking the time to put up this detailed description. Just this spring, I inherited a beautiful Seth Thomas No. 70 Regulator (second beat, #68 movement, late 1920's vintage). The clock runs very reliable. It obviously was used as a master clock since it has wires and connections for batteries and for the slave clocks. There's no self wind mechanism and nothing for bells. Anyway, all the switches and solenoids have been stripped out of the clock, other than the snubbing resistors and the wires. I was very interested on how the clock managed a once-per-minute switch closure to activate the slave solenoid and slave clocks, and now everything is perfectly clear. Perhaps Seth Thomas did the minute switch contacts a bit different, but I get the general idea. I plan to do a KZbin video on the clock and movement later this year. Thanks again.

[@chip2139]

I worked for Standard in the Washington DC branch from 1972 to 1978. Standard was still servicing those clocks, I received training on those clocks. I think the working voltage was 36 VDC. The slave clocks were 24 volts dc. The Tape systen is the program machine. It is like a slave clock. Impulse is 24 VDC Correction voltage is 48 VDC.

[@shedactivist]

Great video. Thanks for taking the time to produce it. Very useful to me because I have a similar master and programmable slave clock that needs my attention.

[@MinnesotaClocksandWatches]

I'm very glad you are finding them helpful. They are such cool clocks. What type of clock do you have?

[@shedactivist]

@@MinnesotaClocksandWatches I have a 1950's National Time Recorder Co. master clock which is self winding like the one in your video. It has a mercury switch that tilts once a minute to wind and send a pulse to the programmable slave. That is also a NTR with two program wheels, one for a bell and one for periodic on/off function, plus a day cam. It also has a clockwork bell duration timer. I love them but they don't run reliably so I need to work on them.

[@MinnesotaClocksandWatches]

Cool - that sounds more similar to the International Time Recording clock that I showed in the project introduction video. My ITR from 1925 still uses dry contacts - a mercury switch would be an improvement. It's interesting how long pendulum clocks stayed in service before being replaced by synchronous electric - I guess it's hard to improve on a good design.

[@shedactivist]

@@MinnesotaClocksandWatches Yes indeed, but I am still amazed at the amount of engineering and ingenuity required just to make a bell ring for 10 seconds.

[@cliveperryman3242]

Where and which collection are these clocks , are some from Upton Hall Institute in Newark Lincs ??

[@MinnesotaClocksandWatches]

These are part of my private collection in Minnesota. I have a couple new ones that I just acquired - trying to find time to work on them!

[@shedactivist]

I saw another way to determine voltage by measuring the resistance of the solenoid coil and use Ohms law with an assumed maximum of 0.5 Amps. That would quickly get you into the ball park. My clocks run on 12 volts and they do indeed draw 0.5Amps for the winding solenoid. 6 volts is not enough but it showed me that 24 volts would be too much.

[@MinnesotaClocksandWatches]

That's definitely another approach. After you experiment to find the voltage that drives the clock reliably, you can calculate the current consumption of each component from the measured resistance of the coils. I had data logging equipment, so I was able to get a wholistic view of the clock as sometimes multiple things happen at once, and seeing it graphed out over the run cycle was convenient.

[@Inkreptile]

You measured the resistor wrong... Don't touch the probes or you put your body resistance in parallel wich gives a wrong value other then that nice video

[@MinnesotaClocksandWatches]

Resistance between fingers is on the order of millions of ohms, especially during a Minnesota winter. My example was a 50 ohm resistor. You are right in principle that if I was looking for an accurate value I would have setup differently, but in this case, my finger resistance had absolutely no impact on the concept I was trying to demonstrate.