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A clock driven by a synchronous motor is in principle as accurate as the line frequency of its power source. (Although small frequency drifts will occur over any given several hours, grid operators actively adjust line frequency in later periods to compensate, thereby keeping motor-driven clocks accurate; see Utility frequency § Stability .)
Synchronous motor clocks are rugged because they do not have a delicate pendulum or balance wheel. However, a temporary power outage will stop the clock, which will show the wrong time when power is restored. Some synchronous clocks (e.g. Telechron) have an indicator which shows if it has stopped and restarted.
The electric clock market grew rapidly in the 1930s, and Telechron's patented power interruption indicator gave his clocks an advantage over competing synchronous clocks, but by the 1950s battery-operated clocks that weren't dependent on the power grid took market share, and in the 1960s the quartz clock replaced synchronous clocks.
Upon discovering the Telechron technology, Hammond designed a motor that was synchronous, like Warren's, that is to say, it rotated at a speed that was tied to the frequency of the current supplied by the power grid. In this way, any clock operated by such a motor would run with great precision as long as the operators of the power grid kept ...
In an alternating current (AC) electric power system, synchronization is the process of matching the frequency, phase and voltage of a generator or other source to an electrical grid in order to transfer power. If two unconnected segments of a grid are to be connected to each other, they cannot safely exchange AC power until they are synchronized.
Reluctance motor subtypes include synchronous, variable, switched and variable stepping. Reluctance motors can deliver high power density at low cost, making them attractive for many applications. Disadvantages include high torque ripple (the difference between maximum and minimum torque during one revolution) when operated at low speed, and ...
Clock synchronization is a topic in computer science and engineering that aims to coordinate otherwise independent clocks. Even when initially set accurately, real clocks will differ after some amount of time due to clock drift , caused by clocks counting time at slightly different rates.
Telecommunication networks rely on the use of highly accurate primary reference clocks which are distributed network-wide using synchronization links and synchronization supply units. Ideally, clocks in a telecommunications network are synchronous, controlled to run at identical rates, or at the same mean rate with a fixed relative phase ...