HA42A6 by Danaher

The HA42A6 timer is produced by Danaher and belongs to the Timers and Controllers series. It is a cam-operated industrial component intended for panel mounting in automated equipment where precise, short-range sequencing is required. When energized, its synchronous motor advances the internal cam stack so that preset contacts transfer at scheduled points within a cycle, coordinating downstream actuators, heaters, or motor starters without a separate PLC. This design suits conveyor indexing, packaging, and dwell applications that call for repeatable timing over intervals of less than one minute.

The HA42A6 switching hardware is rated for 15 A, enabling direct control of most pilot-duty coils and small motors. Each pole uses contacts faced with silver, a material chosen for low contact resistance and minimal arc erosion when interrupting inductive loads. A total of 3 independent contact sets allows separate circuits to operate through a single timed cycle. The operator dial drives the cam through a 20:1 turn ratio, so one full revolution of the pointer produces twenty revolutions of the timing gear and provides fine angular resolution. Users can select any interval from zero up to the maximum setting of 120 s, allowing the timer to support multiple dwell lengths without mechanical changes.

Clear operator interaction is provided by a 4 in outer dial that remains legible in typical machine enclosures. After each run, the mechanism returns to its starting position through an electrically operated reset coil, permitting automatic rearming from a control relay instead of requiring manual spring winding. The synchronous motor is calibrated for a mains frequency of 60 Hz, so the cam advances at a constant rate proportional to the line frequency. Nominal power is supplied at 120 VAC, allowing the timer to operate with standard North American control transformers without a separate power supply.