Tasasuuntauskellot

Tasasuuntauskellot, also known as synchronous clocks or synchronous motors in clock mechanisms, are timekeeping devices that utilize a synchronous motor to drive the clock's hands. Unlike purely mechanical clocks that rely on weights or springs, tasasuuntauskellot derive their power and timing from an alternating current (AC) electrical supply. The synchronous motor within these clocks is designed to rotate at a precise speed directly proportional to the frequency of the AC power grid.

The fundamental principle behind a tasasuuntauskellot is that the AC power source provides a consistent and stable frequency, typically 50 or 60 Hertz depending on the region. The synchronous motor's rotor is designed to lock onto this rotating magnetic field generated by the AC current. This ensures that the motor's rotation speed remains constant as long as the power supply's frequency is stable. This consistent rotation is then transferred through a gear train to move the clock's hour, minute, and second hands at their correct relative speeds, thus indicating the accurate time.

The accuracy of a tasasuuntauskellot is directly dependent on the stability of the electrical grid's frequency. Historically, these clocks were very popular due to their inherent accuracy and low maintenance requirements compared to some mechanical clocks. They eliminated the need for manual winding or regular adjustments for timekeeping. However, with advancements in quartz and atomic clock technology, the prevalence of tasasuuntauskellot has decreased in favor of more precise and independent timekeeping solutions. Despite this, they can still be found in older installations or in specific applications where grid synchronization is deemed sufficient.