The Airpax™ AP series are fully sealed, magnetic circuit protectors that combine power switching and accurate, reliable circuit protection with inverse time delays and trip free features.
Unlike a thermal circuit protector, the AP does not change its trip current over a wide temperature span. In addition, the AP magnetic circuit protector is available in either DC, 50/60Hz or 400Hz versions and with various delays to match the protector to specific application requirements.

One of the most important features of this protector is the “trip free” action, which means the circuit will not remain closed in the presence of an overload even though the handle is held in the ON position. The delay mechanism senses the fault and the contacts open. Waterproof panel integrity is provided by an “O” ring bushing seal and a silicon rubber gland within the bushing/handle assembly. Salt spray testing per MIL-STD-202, Method 101, Test Condition B, with no evidence of corrosion, electrical or mechanical damage.

Typical applications include communication, navigation and aircraft instrumentation, radar and power supplies. The Airpax™ UP circuit protector, with UL recognition and CSA certification, is essentially the same as the AP in construction and operating principle. It is approved for operation at 50 volts DC to 20 amperes, 120 volts 50/60Hz to 15 amperes and 240 volts 50/60Hz to 7.5 amperes.

The UP circuit protector is available in single pole units only, due to UL and CSA creepage specifications and the wide glass terminals utilized. The Airpax™ AP-MIL protectors are produced in accordance with MIL-PRF-39019 and the pertinent specification sheets, are subjected to an exacting production and test program to maintain their Qualified Products Listing (QPL).

One, two and three pole series trip units, with or without auxiliary contacts, have been accepted for this listing. Refer to specification sheets MIL-PRF-39019/1 through 6 for the application government designations. The AIRPAX cage code number is 81541.