Product Description:

The HP55A601 is an electromechanical preset timer produced by Danaher within the Timers and Controllers series. It inserts a controllable delay between an incoming 120 V control signal and the switching of its output contacts, allowing the timer to pace indexing tables, washing systems, or conveyor sections without a PLC. A synchronous motor, a reversible clutch, and a front dial convert line frequency into predictable elapsed time. The panel-mounted design allows timing adjustments to be made directly from the front of the device without opening the control enclosure.

The device runs directly from a single-phase 120 VAC at 60 Hz source, so no auxiliary power conversion is necessary. When line voltage is applied, the armature pulls in after an average of 28 ms, establishing the initial timing reference. The double-pole contacts can switch up to 10 A at 120 VAC, making them suitable for small pump motors or solenoid banks. Any timing interval up to 30 min can be selected by rotating the dial, which is marked in half-minute divisions. Across successive cycles, the mechanical train limits drift to within ±9 sec, providing repeatability for processes that require consistent soak or dwell periods.

During energization, the coil experiences a 10 A inrush and stabilizes as the motor load settles at 2.45 VA. The reverse clutch transmits torque with a supply burden of only 10.5 VA. Once a timing sequence finishes, the contacts release in 17 ms, and the mechanism fully rearms in 0.5 sec so another cycle can begin without a lengthy delay. For short timing cycles, the dial can be set to a minimum of 1 min. Connection to the control wiring is simplified by a terminal block with 15 numbered screw positions. These positions keep the motor, clutch, and contact connections clearly separated for easier wiring and fault isolation.