Standard Electric Time Co. S-1-24 Timer

Brooke Clarke 2007

Standard Electric
          Time Co. Time Interval Counter S-1-24


Before electronic counters, like the HP vacuum tube neon 500 series that used the AC4A decade counting module analog mechanical methods were used.  This prrticular model is DC powered and counts in milli seconds.  The 6,000 RPM (100 Rev/sec) 27 VDC motor is geared down by 50 times so the fast hand moves at 2 Rev/sec.  The slow hand counts in half seconds up to 15 seconds.

There are 4 electromagnetic components:
The instructions say to let the motor run for three minutes before making a measurement.  Depending on how the two toggle switches are set you can make different types of measurements.  With both switches off the clutch engates when +27 volts is on terminal "I" and stops when the input stops, so measures pulse width.  With both switches on the timer starts like before, but the relays latch and hold so the timer keeps running after "I" goes low.  It stops when input "II" goes high thus making a time interval measurement.

If you know of any applications where these were used by the Air Force (Army Air Force?) or have a manual please let me know.


Standard Electric Time Co. S-1-24 Inside View
Although made in 1951 it still functions, although I haven't checked the calibration.  It makes a sound that I remember hearing in movies, maybe of atomic bomb tests or some other scientific experiment.  It has a distinctive sound.

There is some type of soft fuzzy off white substance on some of the shiny metal surfaces.  For example the zero lever going from the lower left post up and to the right is completly covered with it.  The screw in the lower right has it's head covered.  The screws on the back of the relays are shiny and clean.  It wipes off easily, but if not cleaned will come loose and get on the dial or other parts. 

I think it's possible to dissassemble the clock work while leaving all the electromagnetic items connected to thier wires.  That would allow cleaning the mechanical parts and putting fresh modern lubricants on.

If you have any maintanance information let me know.

The zero lever from the lower left post that goes up and to the right is coated with the fluffy substance as is the screw head at the lower right.  But the screws on the back of the relays are not coated.  If you know what this is please let me know.
The relays were made by C. P. Clare.  The motor made by Delco div of General Motors.  The motor appears to have a cast iron case.  To the left are the two brushes and the worm 50:1 reduction gear.  To the right is the governor.

Model Numbers

These timers were made with different speeds:
Fast Hand
Time for 360
Fast Hand
one tick
Slow Hand
Time for 360
                  Electric Time Co. S-1-24 Stop Clock dial
S-1-24 0.5 sec
0.001 sec
30 min
24 VDC 24 VDC
Standard Electric Time Co. S-1 Stop Clock
1 sec
1/100 sec
60 sec (1 min)
24 VDC 115 VAC
Standard Electric
                  Time Co. S-60 Stop Clock
60 sec
0.2 sec
60 min
115 VAC
S-10 Standard Electric Time Co Timer
1- sec
0.1 sec
1000 sec

115 VAC


Standard Electric Time Co. Slave Clock -
2058712 Stop Clock, W.M. Bristol (Thompson Clock Co.), Oct 27, 1936, 368/112 ; 310/41; 310/77; 477/21; 968/839


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  page created 18 Oct 2007