"dpb" wrote in message ...
Travis Jordan wrote:
wrote in message
oups.com...
I just wired up an Intermatic T103 timer. I noticed after 12 hours
the timer seems to be moving to fast (12 hours registered about 13
hours on the timer). Could I have a wiring issue or is this just a
faulty clock timer? TIA.

That timer uses a simple synchronous clock motor timer that depends on
the 60Hz AC power for accuracy. If the clock motor runs at all it is
probably keeping time. ...

The accuracy of the input doesn't guarantee the accuracy of the output if
it isn't manufactured under precise (enough) tolerances...

The synchronous motor drives a set of fixed tooth gears which in turn drive
the time display. "Manufacturing tolerances" won't cause the timing
accuracy to change. The only probable cause for one of these timers to gain
or lose time is either a) operating a 50 Hz timer on a 60 Hz supply, or
vice-versa, or b) a power outage.

http://www.allaboutcircuits.com/vol_2/chpt_13/2.html