Does the clock keep accurate time?
The motor is based on your power frequency supplied by the power company. The clock will keep time as good as they supply the line frequency. I would expect it to stay within one minute to a few seconds of the actually time throughout the day, but it can vary depending on where you live.
What If I live outside the US with 50 hz power?
If you live in a 50hz country, there is a different gear and back wall in the plans so your clock will keep time where you live.