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Low-Profile Secondary Power Distribution

Power Distribution Unit

Ultra-Thin Design

AMETEK's low-profile solid-state secondary power distribution units (SPDUs) replace centralized circuit breaker and relay panels to provide a more advanced, smaller, and lighter weight solution of power management. These SPDUs are designed to be remotely located throughout the aircraft and managed using a robust digital data bus. The result is significant system and harness weight savings and the ability to easily accommodate customizations that are commonplace in interior and VIP aircraft designs. Along with superior circuit protection, our solid-state SPDUs provide enhanced integration and maintenance benefits, including automated load control capability and electrical system health monitoring consolidated into a single, lightweight box.

Our low-profile SPDU is a thin, flat packaged array of AC or DC thermally mounted Solid State Power Controllers (SSPC) on a carrier board, offering a RS485 control bus. Each SPDU has provisions for master reset and each individual SSPC can be addressed, and each output status can be displayed. Each SPDU connects to a field adjustable personality module that customizes each output on the SPDU to a specific current rating.

Reduce Aircraft Wiring

Using a distributed power control system greatly reduces the amount of wiring needed since each wire is not required to route to a centralized location. Reducing the wire runs simplifies installation, saves weight, and increases power system reliability.

Programmable Over-Current Trip Capability

The SPDU has a removable personality module that allows each circuit to be easily set for different load applications. For example, a 15A circuit can be set down to a 10A circuit by turning an adjustment screw in the personality module. This provides for very flexible installation and the SPDU can be adjusted for future aircraft modifications. No longer is it necessary to stock multiple part number circuit breakers for different loads.

Arc Fault Detection

Our technology solutions sensing capability can also be used to trip on intermittent arc faults produced by wire insulation failure. The arc fault sensing is designed to recognize the unique signature of an arc without tripping on turn-on transients from motors, lamps, etc. The ability to detect arc faults is an added feature that increases safety in aircraft power distribution and complies with new certification requirements.

Unique Failsafe Design

Unlike other solid-state products, the SPDU contains patented circuitry that prevents a failure in a short-circuited condition. This means that a failure will not cause a critical load to remain powered in an unprotected and uncontrolled manner. 


Our SPDUs provide digital bus control of all electrical devices up to 45A DC or AC per unit. Reliability is also dramatically increased since solid-state switches do not wear out like conventional circuit breakers or relays.

Features and Benefits:
  • Detachable personality module allows easy customization
  • AC = 12 channels, DC = 16 channels
  • Monitor load voltage, current, trip status
  • Replaceable bus bar mounted contactors
  • RS-485  data bus control and monitoring of all outputs
  • Attractive solution based on weight, size, and performance
  • No active cooling required
  • Remote mounting simplifies aircraft design
  • DO-178B, level A software
  • Qualified for use in non-environmentally controlled areas of the aircraft
  • Patented "Fail Open" technology - will not fail short