Addressing the Big Questions of Partial Discharge

June 11, 2021 Michael Traskos

In this high-voltage present, wires and cables must address new challenges, perhaps the most notable is partial discharge (also referred to as corona). This article discusses the fundamentals of partial discharge, its impacts on wiring design, and test methods used to assess a component’s partial discharge performance. The PD may occur between (1) the conductor and insulation, (2) within void in the insulation, (3) between insulation layers, or (4) between the insulation surface and shield. Read more

Impact of Secondary Wire Harness Protection on Heating

December 10, 2019 Michael Traskos

If you are standing outside on a cold winter day, would you be warmer in a T-shirt or in a jacket? The answer is obvious, but somehow that ‘obvious answer’ is obscured when thinking of aircraft wire harness design. A common question of OEMs and aftermarket modifiers is: how much of an impact (if any) does secondary harness protection have on wire harness heating?

Lectromec took time this last week to put together a representative harness and run tests to generate data on the thermal impact of three secondary wire harness protection schemes. While this data is not representative of every wire harness configuration, it does provide a basis for determining if additional testing (or simulation) are needed for your application.

Getting the Right Bonds

November 22, 2019 Michael Traskos

Things were so much easier with aluminum aircraft structures. The structure acted as an EMI shield, electrical grounding could be done right to the structure without additional effort, and the electrical mating of the structure was straight forward. Now, with composite structures, aircraft design concepts such as electrical bonding, particularly in the case of handling lightning strikes, becomes more important.

When done right, the impact of a lightning strike should have a limited impact.

In this article, we review the concepts around primary aircraft bonding, its requirements, and the implementation as they relate to lightning strike.

Shield Grounding and EMI Protection

March 5, 2018 Michael Traskos

The push for more electric aircraft is driven by weight savings and the availability of reliable electrical components. This is made possible with greater power generating capacity, however, this comes with an increased challenge of ensuring reliable data transmission. More power flowing through the aircraft means higher levels of electromagnetic interference (EMI). Aerospace environmental test […] Read more

Evaluating Secondary Wire Harness Protection Performance

October 4, 2017 Michael Traskos

There are several reasons to deploy secondary harness protection (SHP): chafe protection, maintenance protection, fire protection, harness cable management and, in some cases, arc protection. The EN6059-502 test examines secondary harness protections and the potential damage from arcing. This article runs through the test method and problems that could occur if the results are misinterpreted. […] Read more

Fuel System Protection Part II

July 19, 2017 Michael Traskos

Lectromec has written multiple articles on fuel system safety as it relates to SFAR88, AC 25.981, and AC 25.1701. In this article, we continue the discussion by reviewing some of the recommendations that came out of the NTSB report on TWA 800 and subsequently influenced AC 25.981. Some of these recommendations may not apply to […] Read more

Signs of an Aging Wiring System

May 1, 2017 Michael Traskos

All components wear out over time, but the rate at which they degrade will vary depending on the quality of the product, how is it handled, and the environmental conditions in which the component is installed. To consider all the potential ways that an EWIS can fail, it can be overwhelming. As a brief list […] Read more

Nuisance Trips

December 16, 2016 Michael Traskos

Circuit protection devices are primarily responsible for protection of electrical circuits from low impedance faults. These device types may be thermal, arc fault circuit breaker (AFCB), or integrated within a solid-state power distribution. Regardless of type, their role remains the same. But circuit protection devices are not error free. In the cases when the circuit […] Read more

Ampacity Improvements

October 24, 2016 Michael Traskos

When electrical current flows down a conductor, it gets warm due to resistive heating. The more current that flows, the warmer the conductor gets. Depending on the wire gauge, conductor conductivity, and ambient temperature of the wire location, the conductor temperature reaches the maximum certified temperature. This maximum electrical current is where the outward heat […] Read more

What are the Potential Issues with Tin Plated Conductors?

September 11, 2016 Tristan Epp Schmidt

Tin plated copper is a common choice for wire conductor within the aerospace industry. The advantages of using tin as the plating for copper conductors is the low cost, increases to solderability, and corrosion resistance. However, tin-plated conductor does have drawbacks. Here we review some on the key differences between common platings for aerospace wires. Read more

Protection & Prevention