The Eureka Governor is an electronic power supply for the antique English Eureka battery clock that will make them keep quartz accurate time. It requires no changes to the clock, and simply takes the place of the existing battery. I have been making a Governor for more than 20 years. I have refined the design for 2025 with several new features:
- It regulates an English Eureka clock to run at a quartz-accurate rate.
- It allows an adjustable drive voltage to the Eureka clock from 2 to 5 volts.
- It has screw terminals for batteries to allow for your choice of holders. It includes a holder for four ‘C’ cells.
- It has a jack where you can plug in a MicroSet Clock Timer to measure the Eureka rate for setup.
- It has a calibration Mode with an LED to indicate if the Eureka is slow, fast, or within the capture range.
- If the Eureka is too slow the LED blinks 3 times slowly.
- If the Eureka is too fast the LED blinks 10 times quickly.
- If the Eureka is within the capture range the LED stays on solidly for 2 seconds.
The Eureka Governor works by turning the batteries on and off at precisely timed intervals. This causes the clock to fall into synchronization with the quartz timed pulses. No modifications to the clock are required, preserving the value and original design of the clock. After installation of the Governor the clock looks and behaves no differently, except that it always shows the correct time!
The Governor includes a high efficiency voltage regulator which allows you to tailor the voltage to your individual clock. You can also increase or decrease the amplitude by making adjustments to the operating voltage.
Shown below is a MicroSet graph of a Eureka clock running with the Governor installed. The correct rate for a Eureka is 2700 BPH. At the left side ofthe graph the clock is running intentionally slow, around2695 BPH. A third of the way in the clock synchronizes to the timebase in the Governor. You can see the action of the Governor as the rate then speeds up and slows down around the center of the graph. The cumulative error for this clock is a second per month, which is the accuracy of the hand-tuned quartz crystal. (The graph shows an error of 3.3 minutes per day because the first third is unregulated.)
You can order a Eureka Governor 2025 at the bottom of the MicroSet Order Form.
