About the Telechron Master Clock Type A

The Telechron Master Clock Model A represents one of the most sophisticated synchronous electric master clocks ever manufactured. Designed and built by the Warren Telechron Company of Ashland, Massachusetts, this clock was the backbone of time distribution systems in power plants, telephone exchanges, and large institutional buildings during the mid-twentieth century.

Unlike traditional pendulum master clocks, the Telechron Master A uses a synchronous electric motor locked to the 60-cycle (60 Hz) alternating current power grid. This means the clock's accuracy is directly tied to the accuracy of the power grid frequency, which in the United States is maintained to extremely tight tolerances over a 24-hour period. The result is a clock that requires no manual regulation and maintains accuracy indefinitely without adjustment.

The Three-Face Design

One of the most distinctive features of the Model A is its three-dial arrangement:

• Primary dial -- Displays the current time driven directly by the main synchronous motor. This is the "official" time.
• Backup dial -- An independent time display that serves as a check on the primary. If the two dials ever disagree, it indicates a malfunction in the drive train.
• Elapsed time / program dial -- Used for timing events or controlling program tapes that trigger bells, signals, or other timed actions throughout a building.

The Restoration Project

This restoration project involved bringing a Telechron Master A back to full operational condition. The work included:

• Case restoration -- The original oak case was stripped, repaired, and refinished to its factory appearance. Missing hardware was sourced from period-correct suppliers.
• Motor servicing -- The synchronous motor was disassembled, cleaned, and inspected. The bearings were checked and lubricated.
• Dial restoration -- All three dial faces were carefully cleaned and any faded markings were restored.
• Electrical work -- All wiring was inspected and replaced where deteriorated. The pendulum drive coil for slave clock synchronization was tested and verified.

The final result is a fully operational Telechron Master A that runs accurately on modern 60 Hz power, just as it did when it left the factory decades ago.