AP/UP, AP/MIL Series
Magnetic Circuit Protectors
Introduction 71
Poles 72
Configurations 75
Operating Characteristics 76
Delay Curves 77
Specifications 78
Decision Tables 79AP/UP, AP/MIL Series
Hydraulic Magnetic Circuit Protectors
INTRODUCTION
The Airpax AP series are fully sealed, magnetic circuit Typical applications include communication, navigation and
protectors that combine power switching and accurate, reliable aircraft instrumentation, radar and power supplies.
circuit protection with inverse time delays and trip free features.
The Airpax UP circuit protector, with UL recognition and CSA
Unlike a thermal circuit protector, the AP does not change its certification, is essentially the same as the AP in construction
trip current over a wide temperature span. In addition, the AP and operating principle. It is approved for operation at 50 volts
magnetic circuit protector is available in either DC, 50/60Hz or DC to 20 amperes, 120 volts 50/60Hz to 15 amperes and 240 volts
400Hz versions and with various delays to match the protector to 50/60Hz to 7.5 amperes. The UP circuit protector is available in
specific application requirements. single pole units only, due to UL and CSA creepage specifications
and the wide glass terminals utilized. The UP series offers an
One of the most important features of this protector is the trip optional FM approval (Factory Mutual Research), provided for
petrochemical applications. FM approval is available for single
free action, which means the circuit will not remain closed in
pole, series trip, UP type units only.
the presence of an overload even though the handle is held in
the ON position. The delay mechanism senses the fault and the
The Airpax AP-MIL protectors are produced in accordance
contacts open.
with MIL-PRF-39019 and the pertinent specification sheets,
are subjected to an exacting production and test program to
Waterproof panel integrity is provided by an O ring bushing
maintain their Qualified Products Listing (QPL). One, two and
seal and a silicon rubber gland within the bushing/handle
three pole series trip units, with or without auxiliary contacts,
assembly. Salt spray testing per MIL-STD-202, Method 101,
have been accepted for this listing. Refer to specification sheets
Test Condition B, with no evidence of corrosion, electrical or
MIL-PRF-39019/1 through 6 for the application government
mechanical damage.
designations. The AIRPAX cage code number is 81541.
AP Series - Introduction
71