HA40A6 by Danaher

The HA40A6 timer is produced by Danaher within the Timers and Controllers series. It is an on-delay cam timer used to coordinate sequential machine operations, such as clutch engagement, heater dwell, or conveyor indexing, by opening and closing multiple power contacts at fixed delays. In industrial automation, it provides repeatable short-cycle timing so electromechanical actuators receive consistent energized periods under line-frequency power.

Power for the HA40A6 is supplied at 120 VAC, allowing direct connection to common control transformers. Its internal synchronous motor is tuned to a 60 Hz line, so the dial graduations maintain linear time-base accuracy without electronic calibration. Each of the three DPDT contact decks carries up to 15 A of resistive load, and the movable elements are tipped with silver to keep contact resistance low over thousands of cycles. The dial mechanism features a 20:1 turn ratio, meaning a full revolution of the outer knob represents twenty revolutions of the timing gear train. This ratio provides fine resolution when setting short delays. Rotation is driven by a synchronous motor through a solenoid-released clutch, so the timer remains idle until an upstream coil pulse couples the drive to the cam stack.

The timing scale extends to a maximum of 20 s, enabling rapid indexing tasks without overshoot. The timer has 3 isolated contact sets that permit simultaneous control of separate loads while sharing the same time base. A broad 4-inch outer dial improves readability during manual adjustment on a panel door. After the cycle is complete, an electric reset circuit returns the clutch to its disengaged state, readying the cams for the next start signal. The solenoid actuation system eliminates manual reset levers, keeping enclosure fronts sealed, while the silver contacts limit arcing during high-inrush events.