Product Description:

The 0123935-689 is a shaft-driven electromechanical preset counter manufactured by Danaher within the Timers and Controllers series. It advances its five-digit register with counterclockwise rotation of a right-hand shaft, allowing production equipment to accumulate counts without electronic sensors. A base-mount footprint simplifies fastening to machine plates, and the mechanism trips an internal switch at the chosen preset so downstream controls can start or stop processes. The counter supports batch sizing and position tracking in automated production lines where a mechanically driven counting mechanism is preferred.

The shaft can be driven at up to 2500 rpm, while the internal pawl accurately registers pulses at a maximum rate of 5000 cpm. Each revolution must overcome 4 oz-in (2.83 N·cm) of static torque, so light belts or gear trains can turn the unit without slipping. The spindle measures 1/4 in (6.35 mm) in diameter, matching commonly available couplings. When the preselector reaches 99,999, an isolated output becomes active, and the five counting wheels display the terminal value with characters measuring 0.206 × 0.150 in. The contacts can directly switch loads of up to 20 A at 115 VAC for connected heaters, solenoids, or motor starters.

The housing is molded from Zamak, a zinc-based alloy that resists corrosion from machine oil and provides dimensional rigidity for the gear train. The contacts use an SPDT arrangement, allowing either the normally closed or normally open circuit to be routed through the same terminal block. After a batch is finished, the register can be restored using a manual reset knob. The smaller preset wheels have characters measuring 0.165 × 0.120 in and allow the desired target to be selected in a single movement. The assembly weighs 2 lb 9 oz (1.16 kg), making it suitable for installation on compact index tables while providing enough mass to damp vibration that could otherwise cause false counts.