Who Uses 400 Hz Systems?


400 Hz systems are mostly used in avionics, military, shipboard, and aerospace applications. Commercial airlines, the military, and their contractors are the main users of these higher frequency power systems.


How 400 Hz is Superior to 50 & 60 Hz


In certain applications, there is a substantial benefit to be gained in minimizing volume and weight. Obviously anything that is lifted aloft and/or continually flown aloft takes appreciable energy and it occupies precious space in the aircraft. These same restraints apply to mobile military equipment and command centers where transport energy (whether on the ground or in the air) can be a strategic limitation and volume requirements are always to be minimized. Transformers for 50 or 60 Hz power and power supplies are inherently much larger and heavier than 400Hz components and thus are avoided in many such applications. Originating in World War II military aircraft, the advantages of 400Hz have caused it to spread widely throughout the military (air, land, and sea) and throughout civilian aircraft. When space and weight are the deciding factor, the disadvantages of 400Hz are always outweighed.


Is Power Quality Important in 400 Hz systems?


Just like any power system, power quality is very important in a 400 Hz system. In an aircraft where critical flight instruments rely on the power supply, having consistently well-functioning equipment is of the highest priority. A reliable power quality analyzer can tell you everything about the health of a system’s power over time, not just the basic power measurements. Whether performing a routine check or troubleshooting an issue, knowing the power quality of a 400 Hz system can be imperative in resolving power concerns before they become threatening. Predictive maintenance and load studies can be easy and successful with the right testing tool. Owning a high quality power analyzer is like having a multimeter, harmonic analyzer, power meter, and oscilloscope all in one. A capable 400Hz power quality analyzer will measure, log, and capture all aspects of power and have many more advanced measurement capabilities than most other common testing tools.

Applications for Power Quality

  • Evaluate Quality of Incoming Power (swells/sags/outages/high-speed transients at service entrance or generator output)
  • Evaluate Quality of Power Within Circuits to Find Failure Causes (swells/sags/inrush/high-speed transients)
  • Evaluate Harmonic Distortion of Power (THD profiles over time)
  • Verify ATS & Backup Power (outage/recovery/inrush)
  • High Frequency Studies (power-line spectrum analysis to 100KHz)

Conventional Power Monitoring Applications

  • Long, Extended Studies
  • Cost & Efficiency Analysis
  • Power Factor Mitigation
  • Evaluation of Motor Health

Power Analyzers that Can Safely Monitor 400 Hz Systems


Not every power analyzer has what it takes to monitor 400 Hz; most are limited to 50 Hz or 60 Hz. Here are the PowerSight complete power analysis systems that fit the bill for avionics/military power studies.

PowerSight Analyzer System Meter Type Current Probes 1kV Voltage Leads Captures Transients / Sag / Swell / Inrush Price
Power Analyzer 4 flexible YES NO $4,290
Power Quality Analyzer 4 flexible YES YES $6,995
Power Quality Analyzer 4 flexible YES YES $7,540