Circuit Breakers


Hydraulic-magnetic circuit breakers offer precise, specification assured, nuisance free circuit protection.

What do they do?

Tolerant of the shock and vibration that’s so common on rolling stock, they are unaffected by high inrush currents and will only trip at their rated capacity. They can be specified with differing time delay curves to compensate for electrical anomalies. There are many options available to permit customisation to the application including integrated auxiliary switches, alarms, remote off indicators and illuminated rockers.

The accurate and efficient protection offered by Rowe Hankins products ensures continuous and steady operation of Uninterrupted Power Supplies (UPS) units.

The magnetic time-delay circuit breaker operates on the solenoid principle where a movable core held with a spring, in a tube, and damped with a fluid, may be moved by the magnetic field of a series coil. As the core moves toward a pole piece, the reluctance of the magnetic circuit containing the armature is reduced. The armature is then attracted, causing the mechanism to trip and open the contacts on an overload or fault condition.

What are the facts?

  • Trip Free – Will trip open on overload, even when forcibly held on. This prevents operator from damaging the circuit by holding handle in the ON position.
  • Trip Indication – The operating handle moves forcibly and positively to the OFF position on overload.
  • Ambient Operation operates normally in temperatures between -40° C and +85°C.
  • Insulation Resistance.
  • Not less than 100 megaohms at 500Vdc.
  • Dielectric Strength – Shall withstand AC voltage 60 Hz, for 60 seconds between all electrically isolated terminals as described below.
  • Series, switch only : 3,750 VAC.
  • Auxiliary switches : 600 VAC.
  • Series w/ auxiliary switch : 3,750 between main circuit breaker terminal and auxiliary switch terminal.
  • Shock – Shall not trip when tested per MIL-STD-202, method 213, test condition 1 with 100% rated current applied to delayed units, except 90% current in plane 4, (i.e. handle down).
  • Instantaneous units shall have 80% rated current applied in all planes.
  • Vibration – Shall not trip when vibrated per MIL-STD-202, method 204, test condition A with 100% rated current applied to delayed units and 80% rated current to instantaneous units.
  • Endurance – In many applications contact wear due to the electrical load determines unit life. At maximum electrical ratings, the IAR/IUR/IER/CUR/CER can perform 10,000 operations at rated current and voltage at a maximum rate of 6 operations per minute.