Our Testing Services
Our lab contains a wide range of electrical, mechanical, chemical, and environmental test capabilities that can be augmented, adjusted, or modified to meet the needs of your particular applications. The following are some of the services that Lectromec offers.
The Abrasion Resistance test evaluates an insulation's ability to endure rotational abrasion.
This test measures both permittivity and A/C loss of an insulation sample and uses these values to determine a variety of characteristics of said specimen.
Accelerated aging is a test to help predict the long term chemical and mechanical durability of wire/cable insulation materials. Subjected to temperatures in excess of their prescribed rating, insulating materials break down quickly so data that would take months and years to gather can be attained in mere weeks and days.
The accelerated service test evaluates the performance of a finished cable at electric overload conditions.
Accelerated aging is a test to help predict the long term chemical and mechanical durability of wire/cable insulation materials. Subjected to temperatures in excess of their prescribed rating, insulating materials break down quickly so data that would take months and years to gather can be attained in mere weeks and days.
The purpose of adherence of plating is to measures the effectiveness of adherence of the applied plating to conductor. Copper conductors are normally plated with pure metal coatings to improve the conductor performance and reduce resistivity.
The Adhesion of Conductors test measures adhesion of each conductor layer of a cable to the cable's dielectric core.
The adhesion of Nickel coating test evaluates the adherence of a nickel plating to an underlying copper/ copper alloy material.
Life cycling of polyalkene wire is a three step process that starts with placing the wire in a high temperature air circulated oven for a defined period of time. Sustained high temperature exposure is performed followed by mechanical and electrical tests.
The specimens are suspended in a heat chamber without touching one another or the walls for 7 days at the applicable test temperature. After the conditioning period, the specimens are removed from the heat chamber and conditioned at room ambient temperature for 4 hours minimum.
It is no surprise that aircraft components are expected to withstand rapid and extreme changes in altitude without loss of functionality. The altitude immersion test subjects a sample connector to such changes in altitude pressure and assesses its ability to maintain functionality.
Wired, mated, and assembled connectors are tested inside a pressurized chamber with the temperature reduced to simulate an altitude of 100,000 feet. The chamber's internal temperature is reduced to -65 °C and is maintained until the connector temperature stabilizes.
The Armor test consists of two smaller tests, Springiness and Toughness. Each is designed to evaluate the durability of armor wire.
Fiber optic cable attenuation testing is a procedure performed to measure the loss of signal strength or power as it travels through a fiber optic cable. Attenuation refers to the decrease in the intensity of light signals as they propagate along the fiber.
The purpose of attenuation testing is to assess the quality and performance of the fiber optic cable, ensuring that the signal loss is within acceptable limits. By measuring the attenuation, network operators can determine if the cable meets the required specifications and if any corrective actions are necessary.
The testing process typically involves the following steps:
Setup: Prepare the necessary equipment, including a light source and a power meter.
Connector Inspection: Inspect and clean the connectors on both ends of the fiber optic cable to ensure accurate test results.
Launch and Receive Cables: Connect the launch cable (a known good fiber cable) to the light source and the receive cable to the power meter. These cables serve as reference cables and help establish a consistent testing environment.
Measurement: Launch a light signal into the fiber optic cable using the light source and measure the received power using the power meter. The measurement is typically done at multiple wavelengths to account for different light sources used in the network.
Analysis: Calculate the attenuation by comparing the transmitted power with the received power. Attenuation is usually expressed in decibels per kilometer (dB/km) or decibels per meter (dB/m).
Interpretation: Compare the measured attenuation with the acceptable limits specified by the industry standards or the cable manufacturer. If the measured attenuation exceeds the limits, further investigation or corrective actions may be required, such as identifying and repairing any damaged sections or connectors.
Fiber optic cable attenuation testing is crucial for maintaining the performance and reliability of optical communication networks. It helps identify potential issues, such as fiber degradation, faulty connectors, or improper installation, allowing operators to take appropriate measures to optimize network performance.
The purpose of the attenuation test is to measure the energy lost by transmitting a signal through a cable. The energy lost measurement quantifies the cable's resistance to electrical signal transmission.
The axial concentricity quantitatively measures the concentricity of a wire or cable sample as a TIR (Total Indicator Reading) measurement.
The Axial Stability test evaluates the ability of wire/ cable insulation to resist longitudinal dimensional change while cycling between high and low temperatures.
The backshell shield braid to shell conductivity test measures the voltage drop between a connector backshell's shield braid and to either the threads or mounting bracket of the receptacle.
The barometric pressure test evaluates the performance of electrical components at reduced atmospheric pressure such as is expected in high altitude flight.
Coupling components have the potential to undergo high mechanical stress as a result of poor clamping, heavy wire harnesses, and maintenance operations. The intention of the bayonet coupling pin strength test is to assess the strength of the pins in each of the couplings. For this test, a static 50-pound load is applied to the coupling pins to determine if the coupling is structurally sound. The pass/fail conditions are based off of consistent electrical connection and no disengagement of the contact.
This test is used to determine the insulation elasticity and propagation of damage through the wire/cable insulation.
This test determines if a finished wire specimen will block (stick to itself) when subjected to the rated temperature of the specimen. While on an aircraft, wires may be exposed to high temperatures and it important to check if the finished wire specimens are prone to blocking. At the end of the test, we will inspect the wire and examine for adhesion (blocking) of adjacent turns.
Bonding compounds are often used as a means of protecting electrical terminations from the moisture and other contaminates. Furthermore, proper adhesion of potting compounds can have a positive impact on component durability to vibration and mechanical shocks. The bondability of insulation to potting compounds test evaluates the adhesion to the wire/cable insulation.
Piezoelectricity refers to the phenomenon where certain materials generate an electric charge when subjected to mechanical stress or pressure. Conducting a piezoelectricity test on a data cable involves evaluating whether the cable exhibits any piezoelectric properties under specific conditions.
General Test Procedure
Assess the voltage differential on the cable prior to mechanical stress.
Apply a static mechanical load on the cable center point and measure the voltage differential.
Compare the measured data with the baseline measurements taken before the stress application. Assess whether the data cable displays any significant piezoelectric properties. If there is a noticeable change in the electrical response during the test, it indicates the presence of piezoelectricity in the cable.
This test is used to determine the ability of the insulation to withstand the rubbing of one insulation on another in a vibratory environment. Wire's in close contact with other wires can rub on each other on aircraft causing deterioration to the insulation. Different insulation materials have different damage effects to the insulation. The test analyzes the effects of different materials on the test sample.
Knowing the weight of every component on an aircraft, down to the last wire, is vital to good design. This test is to be used to evaluate the weight of a finished cable specimen.
This test measures the capacitance of a cable per unit length. Capacitance is defined as the ratio of voltage between two surfaces divided by their difference in charge.
The Case Insulation Test is a combination of the dielectric withstanding voltage and insulation resistance tests adapted to insulated capacitors.
This test measure the characteristic impedance of a cable defined as the resistance of a transmission line
This test determines the elongation of insulation of a wire in a circumferential direction. This test was developed to measure the resistance of polytetrafluoroethylene (PTFE) insulation to rupture when under a radial stress. Using a power driven apparatus built by Lectromec technicians, a cone shall be driven through the insulation. At the end of the test, the average percent circumferential elongation shall be calculated.
This test determines the resistance of wire insulation to cracking at low temperature while being bent around a mandrel. Using a special cold chamber, we can condition the specimen at the low temperatures that can be experienced during flight and study how it reacts to the extreme conditions. This is a very good way to determine if the wire sample would be able to survive at these typical temperatures. At the end of the test, we will examine for any visible cracks then perform a wet dielectric test for assurance.
The color retention test evaluates an insulation's ability to maintain its color under elevated temperature exposure.
In this test, a contaminate liquid is slowly dripped between two electrodes on the surface of the material. By adding this contamination, electrical conduction between the two electrodes is started and carbonization of the polymer slowly occurs. Once the carbonization occurs and the electrical current exceeds the threshold set on the test, the test is halted, and the voltage is decreased. This continues until sufficient amount of data is gathered to interpolate the number of contaminate drops necessary to achieve the electrical current threshold.
This test determines the diameter of the conductor after the insulation has been removed. This physical test can be very useful when trying to conduct tests or determining if a wire sample can be used in a specific machine. At the end of this test, we will report each measured conductor diameter and the average conductor diameter for each specimen measured.
This test determines a conductor's direct current (DC) resistance at a specified reference temperature (typically set at ambient temperature). There are two methods used to conduct this test known as the Kelvin Bridge Method and the Wheatstone Bridge Method which are used to obtain the resistance of the specimen. Both methods will give similar results, however, the Kelvin Bridge Method is more accurate. At the end of the test, the reported results include the specimen's conductor resistance and the test parameters.
The purpose of this test is to assess the conductor's ability to absorb solder. Soldering is a common method for wiring to connectors on aircraft. Certain conductors plates such as tin and silver are more solderable and thus used for these applications.
Conductor stranding is a quality check method to determine the stranding value. The value is determined by the number of strands times the wire gauge of the strands.
Connectors in any application should be designed to withstand regular mating and unmating throughout their service lives. The connector durability test evaluates this ability by performing a large number of mating and unmating cycles on the connector under test.
The engagement force of a connector contact is an indicator of whether a good electrical connection is made. This test examines the contact engagement forces.
MIL-DTL-26482 compliant connectors must have contact resistance for size 20 is less than30mΩ less than 20mΩ for size 14. Contact resistance is the contribution to the total resistance of a material that comes from the connector.
This test examines the axial force necessray to displace a contact from the proper location when inserted into a connector.
For this test, a pin installed in the connector is crimped to a wire, and the wire is hung over a mandrel with a weight. The connector position relative to the mandrel then undergoes one hundred cycles, effectively stressing the installed pin. Two pins are tested per connector, and the pins in question must not become dislodged to pass the test.
The contamination test measures the quality factor (Q) of a test sample. One end of the specimen is cut square, while the other end is prepared to provide the shortest possible connection to the high terminal of a Q-meter, with the shield connected to a ground terminal. After attaching the specimen, measurements are taken with the Q-meter.
The objective of the continuity of the conductor coating is to examine the quality of the conductor platting before it has been subject to stranding or the insulation application process. Further, this examines the durability of the conductor coating to both mechanical and thermal stresses.
Also referred to as Contrast of Jacket or Contrast Test. The readability of a wire/cable is of critical importance for the proper installation, maintenance, and repair of the wiring system, thus the reason why UV laser marking of wires has become a widely used technology through the aerospace industry and has several benefits over traditional ink marking of wires/cables. The contrast measurement test examination evaluates the contrast of the UV laser marked area with the unmarked parts of the wire.
High voltage spikes onto wires/cables can progressively degrade the insulation performance and lead to an insulation breach and/or create conductive paths through the insulation. In this test, the sample is exposed to a high voltage to determine the corona inception and corona extinction voltage.
Cross-talk occurs when a signal traveling through one cable interferes with another generally in a twisted pair cable.
The crush resistance test method measures the capability of wire insulation to withstand an applied load, simulating the damage that may occur when insulated wire is crushed between two flat surfaces.
In practice, the energy stored in capacitors will dissipate and discharge through the dielectric. The leakage rate is based on a combination of factors that include: the dielectric material, component age, use, temperature, and applied voltage. The DC leakage test is a test that helps to identify the long-term power storage capacity of capacitors and is often included as part of capacitor qualification test plans.
This test is to measure the direct-current (dc) resistance of resistors, electromagnetic windings of components, and conductors. It is not intended that this test apply to the measurement of contact resistance.
This purpose of this test is to evaluate the performance of a cable after installation of plastic cable ties. On aircraft, improper installation of cable ties can cause deterioration to the cable over time.
This test determines if a finished wire specimen will block (stick to itself) or flaring of layers when subjected to the rated temperature of the specimen. While on an aircraft, wires may be exposed to high temperatures and it important to check if the finished wire specimens are prone to blocking or delamination. At the end of the test, we will inspect the wire and examine for adhesion (blocking) and delamination (separation of layers) of adjacent turns.
This test evaluates tape wrapped insulation for sealing between wraps after thermal stress.
A conductor's resistance changes with temperature and is dependent on the conductor's material properties. In this test, the wire is submerged in a oil bath with a temperature accuracy of 0.2C. The bath is progressively heated to the target temperature and the change is conductor resistance is captured at multiple temperature during the test.
This test is typically used as a process control test to ensure that the measured diameter of a manufactured wire is within the range provided in the wire/cable specification. The wire/cable is measured in several locations and the average diameter is reported. For non-uniform cables, such as with twisted pairs, measurements are made both for the minimum and maximum diameter.
The dielectric is perhaps one of the most referenced tests when examining wires. The reason is that it tests the most important part of the wire insulation: determine if the wire insulation is free of breaches (or has been sufficiently degraded such that a high voltage would breach any weak points in the insulation). The basics of the test are that the entire wire, except for an inch at both ends, is placed in a water bath (with salt and wetting agent) and a high voltage potential is placed between the conductor and the return electrode in the water bath. If there is a failure in the insulation, then there will be a noticeable current flow. Dependent on the test method used, the pretest soak time, voltage amplitude and type (AC or DC) will vary.
In particular, this test method examines the performance at different pressures (altitudes). As the atmospheric pressure decreases, so too does the required maximum service voltage to be used in testing.
The dimensional stability test determines the protrusion or contraction of the insulation with respect to the outer conductor on both specimen ends.
The purpose of this test is to measure the dimensions such as gauge and diameter of a cable. The dimensions of a cable determine the amount of electric current or wire rating a wire can carry.
The test evaluates a wire's ability to prevent arc-propagation to other wires in the sample harness.
Electrical connectors are expected to connect and disconnect regularly without degradation for routine activities such as maintenance, replacement, and troubleshooting. The durability test evaluates the ability of an electrical connector to withstand mating and de-mating for a large number of repetitions.
The durometer hardness test is, simply put, a durometer measurement of the hardness of jacket material. The test determines if the jacket material is of adequate harness for use in cable construction.
The dust test evaluates an electronic component's ability to endure an atmosphere laden with dry dust. A component sample is placed in a chamber where circulating fans move the dust laden air at a specified speed.
The dynamic cut-through test is designed to assess the cut-through force of a wire/cable specimen. The wire/cable specimen is compressed under a the fine edge of a jig until contact is made between the wire/cable conductor and the test jig. The pass/fail criteria for this test is based on the wire/cable's specification.
This test measures the degree to which the core conductor of a cable is off-center. In cable design, efforts should be made to ensure the conductive core of a cable is as centered as possible to ensure insulative uniformity throughout.
When using connectors in wire system design, the regular and consistent contact between contacts on both sides of the connector is crucial. To determine this, the electrical engagement test examines the mating length of the connector contacts.
Whether through contamination during maintenance actions, ingress from degraded seals, or other degradation, the fluid ingress into a connector can cause degradation and impact reliability. To assess this, the electrolytic erosion test measures the propensity of connectors to erode when contaminants are present and the connector is in use.
The test consists of introducing a salt-water contaminant to a connector, mating the connector, then energizing the pins for 40 hours at 60 volts. Upon completion, the contacts are examined under magnification for erosion to the base metal.
This test determines if the wire insulation can withstand a temperature aging test for a time period at a temperature greater than the temperature rating of the insulation. The wire must then withstand the bend and wet dielectric tests after the thermal exposure in order to pass. The purpose of the test is to ensure that the insulation will not fail if exposed to extreme heat which may occur while during flight. At the end of this test, we will know which specimens passed or failed by reporting the results of the bend and wet dielectric tests.
Environmental stress crack tests a sample ethylene plastic's susceptibility to cracking as a result of environmental stress and the presence of selected chemicals (soaps, oils, detergents, etc.).
A polarized capacitance bridge is used to measure equivalent series resistance of a capacitor. The Pass/ fail criteria are determined by the product specification sheet.
Samples are visually inspected at 3X magnification to identify defects in the contact(s). A sample will fail the examination if the presence of metal cracks or peeling of the plating is observed.
In this test, the receptacle connector is mounted as in normal service to a rigid panel. Before mating the plug connector to the receptacle, an adapter is attached to the connector. A defined load at a specified rate is applied to the adapter arm then held for one minute. During test test, any circuit discontinuity greater than 1 microsecond will be considered a failure.
This test is a visual examination of particular categories of wire. A Lectromec technician will thoroughly inspect the wire, without magnifying aid, to identify any kinks, cracks, damage, or other abnormalities of the wire.
Flammability is perhaps one of the most common and most important tests performed on aerospace wiring. In general, a length of the wire/cable under test is placed in a draft-free chamber and hung free over a high-temperature flame for 30seconds - 15 minutes (specification dependent). A piece of tissue paper is placed under the sample to catch falling debris.
SAE Test Method: In this test, the specimen is flexed 180Deg between two mandrels until there is a break in electrical conductivity of the conductor. The pass/fail criteria of is based on the particular specification, typically set at a minimum threshold for the number of flexing cycles with conductor loss.
This test evaluates the ability of a terminated wire sample to maintain its structural integrity under conditions of repeated stress at the point of termination. The location of a crimp termination on a wire is more likely to experience conditions of mechanical stress than other locations along the length of the wire. It is crucial in the design of any electrical system for terminations on wires to be physically dependable, particularly in aerospace applications where regular maintenance and movement-related stresses are common.
The flexibility of a wire/cable is dependent on a combination of the conductor and insulation constructions. There are two methods covered by the EN3475 flexibility test, the appropriate method is determined based on the size of the cable under test.
European Test Method: In this test, the specimen is flexed 180Deg between two mandrels until there is a break in electrical conductivity of the conductor. The pass/fail criteria of is based on the particular specification, typically set at a minimum threshold for the number of flexing cycles with conductor loss.
The fluid absorption test evaluates the ability of a cable sleeve to prevent absorption of external fluids. Testing is performed using fluids as identified in the sample's product specification.
The forced hydrolysis test places wire/cable specimen in a high-temperature water bath for an extended duration to evaluate the durability of a wire insulation in high-humidity conditions. Depending on the particular wire specification needs, the test may be required to run for thousands of hours. After the prolonged exposure, the sample is then examined and exposed to a dielectric voltage withstand (DVW) test.
Components that degrade in fuel exposed environments, when located inside of the fuel tank, may break off and create FOD that clogs fuel pumps. Thus, it is necessary to verify the performance of any secondary support product prior to use in these environments.
The purpose of the fungus resistance test is to determine the susceptibility of a specimen to fungus growth on the insulation. To do this, short sections of the specimen are exposed to a variety of common molds/fungus for several weeks then visually examined. A passing specimen will show no fungus growth on the insulation, a failed specimen will show some level of fungus growth susceptibility.
To insure interchangeability between connectors, the mechanical configuration of connectors must remain consistent. The gauge location test verifies connector geometry. A standard test gauge (a test device shaped to particular dimensions) is installed in a connector cavity and the axial location of the front of the gauge is measured against a set reference location to test conformance. The pass/fail criteria for this test is based off of the particular measurements and configuration of the connector under test.
Applicable test instruments, or test gauges, are installed in three randomly selected cavities in each connector. An axial load is applied to individual test gauges in both directions slowly until the maximum load is reached. The displacement of the gauge tool with respect to the connector is reported.
The heat resistance test evaluates the ability of an insulative sample to maintain tensile strength after undergoing an elevated temperature exposure.
The heat shock test evaluates the ability of an insulative material to endure elevated temperature conditions. Slight variations in test setup exist between the test standards covered by this listing and should be considered before choosing which standard best suits your needs.
The bust duct test simulates the condition where a high-temperature, high-pressure air line has ruptured near a wire harness. The test objective is to determine how long the wire/cable can be exposed to these harsh conditions without impacting the insulation reliability.
For this test, contacts are removed and crimped to a wire and then reinstalled. An initial measurement of the axial location is made with an axial load, a specified weight is suspended freely from the contact, and a monitoring circuit connected that senses discontinuities. The connectors are then placed within an oven at elevated temperature. Upon completion and at room temperature, the axial location is re-measured with the same axial load for any discrepancies.
Exposure to humidity is among the most common means of electrical equipment degradation. The humidity testing offers a means of assessing the potential for a in-service connector and/or crimped contact degradation due to heat and humidity. The problems are most pronounced on components with significant imperfections in the component plating. This test seeks to assess the impact of high relative humidity at various temperatures.
The humidity resistance test evaluates the impact of prolonged heat and humidity exposure to wire/cable insulation.
This test examines a connector's resistance to corrosion, and entrance of moisture, long-term durability in high moisture environments. This test method identifies several means of testing a connector in humid conditions.
The impulse dielectric tests can be thought of a production line means of checking for insulation/jacket breaches in wires/cables. In this test, a voltage is placed on the specimen and the specimen is pulled under a 'chain mail' curtain connected to ground. The test is performed at a higher voltage than the standard dielectric tests performed on wires/cables, but this is necessary given the short duration of the voltage differential across the insulation/jacket.
The ASTM B267provides requirements and suggestions in the use of insulated wire coverings such as silk, nylon, cotton, and glass which can be verified at Lectromec.
Measuring the insulation concentricity and wall thickness is a quality assurance test that can identify uniformity issues. Wires with non-uniform insulation (or cables with non-uniform jackets) will have an unbalanced insulation wall thickness that can make the wire/cable more susceptible to mechanical or electrical failure. This test can be performed on wire gauges ranging from 30AWG to 0000AWG and one wholly tape wrapped and extruded constructions.
In this evaluation, the insulation construction of a wire sample is validated by a visual examination at 2x magnification.
This test is to be used to evaluate the cross-linking certain types of wire insulation.
This test determines the insulation resistance of a finished wire sample. Insulation resistance is of interest in high impedance circuits and as an insulation process quality control test. When used as part of a wire/cable environmental testing, prolonged thermal exposure, and/or extended high voltage testing, changes in the insulation resistance can be used as an indicator of insulation deterioration.
This test examines the insulation resistance between connectors pins and the resistance between pins and the connector shell. This test is necessary to identify any manufacturing defects or specimen contamination. The pass/fail criteria conditions for this tests are connector specification specific and have a pin-to-pin and pin-to-shell resistance over 1MOhm.
The insulation shrinkage test objective is to evaluate a wire/cable’s insulation propensity for shrinkage with exposure to elevated temperature.
The insulation stripping test evaluates the ability of insulation to be stripped from a wire sample without causing damage to the conductor.
This test provides tensile property data on extruded electrical wire insulation removed from the wire/cable specimen. Identifying the insulation's tensile properties are useful to determine the ability to withstand mechanical stresses the wire/cable may experience in service conditions.
The insulation volume resistance test verifies that the amount of leakage current from a wire sample is within the acceptable range for a particular application by determining the resistivity of the insulation sample.
This test is to be used to determine whether a specimen will crack when wrapped upon itself or around a mandrel.
Insulation color is often used to identify a wire or cable's system or function(s). The jacket color test evaluates the characteristics of an insulative jacket's color as compared to the limitations specified in the applicable standard.
The jacket flaws test (or spark test) aims to identify any defects in a wire/ cable's outer insulation that would allow an amount of leakage current.
The life cycle test (also referred to as the 'Multi-day heat aging test') seeks to assess short-term elevated temperature exposure to a wire/cable above the sample's temperature rating.
During the degradation process of ETFE and XL-ETFE, fluorine gas is released from the insulation into the environment. This test seeks to quantify the amount of off-gassed material.
The connector is mated and de-mated a dozen or more times. After the mating and de-mating cycles, the installation and removal forces are recorded for each of the contacts.
The long-term readability of wire/cable identification is important for supporting EWIS maintenance operations. A wire/cable with an easily identifiable circuit identification will make it easier to identify the correct circuit in need of evaluation/repair/replacement. If the identification has worn off, then debugging operations may require removing more equipment and/or demating more connectors.
The marking durability test seeks to evaluate the wire/cable identification after abrasion. The pass/fail criteria are based on the individual wire/cable specification but is primarily focused the readability of the wire/cable marks.
This test measures the funtional capacitance between a pair of insulated wires within an multi-pair cable.
The mutual inductance test measures the effectiveness of the insulation on inner conductors within a cable to resist cross-talk induced by adjacent signal-carrying conductors within the same cable.
The Nitric acid immersion test determines the ability of a wire's insulation to resist breakdown in the presence of a strong acid. Test samples are submerged in red fuming nitric acid for a duration of 8 hours. Resistance to the acid is determined via a wet dielectric test - any dielectric breakdown is considered a test failure.
This test is used to calculate the nominal resistance per length based on the resistivity and cross-sectional area of the round wire sample.
The notch test is a test that examines the propagation of nick in the top layer of a wire. Small notches are common during installation or maintenance of wires, and this test evaluates how well the insulation can withstand mechanical stresses after incurring a notch.
The overload resistance test, also known as the smoke resistance test, is designed to examine the durability of the wire insulation under extended periods of internal heating caused by over-current conditions.
A phase constant is a physical property of a propagating sine wave representing the shift in phase the wave experiences while travelling along its path. This test measures the phase constant of a twisted pair cable as a value of radians per length.
Phase delay is a measure of the delay in time a signal is emitted and when it is received at the other end. It is important that signal carrying cable adhere to a minimum phase delay to ensure timely and accurate function of the relevant system(s).
Composite connectors (Class J and M) provide the benefit of a lightweight construction with limited drawbacks. To verify the connector plating in high temperature operation conditions, the plating adhesion test is performed.
For this test, the connector under evaluation is immersed in oil at its operational temperature. It is then quickly cooled to room temperature by immersion in a solvent or ice water. The connectors are then removed and visually examined for any separation or loosening of the plating.
The test is used to determine how thorough the plating process has been performed on conductor specimen when coiled around a mandrel and immersed in a oxidative accelerant.
The post test examination is a visual assessment commonly used after stressing the sample connector. This is an encompassing visual examination of physical nonconformities and possible effects of previously applied testing. This test is typically performed without the aid of magnification.
This test is a visual examination of a tape-wrapped PTFE jacket intended to identify any evidence of delamination.
The Rapid Change of Temperature test evaluates the ability to withstand a series of rapid temperature changes without diminishing its performance.
The chemical composition of a wire's insulation degrades at elevated temperature; this test provides data to establish curves describing the rate of degradation with respect to the exposure temperature.
The Resistance to Electrical Arc test evaluates the efficacy of sleeving/ insulation to protect wires from damage due to electrical arcing.
This test evaluates the ability of cable insulation to resist flame propagation when exposed to fire; for a high quality cable insulation, the flame should extinguish quickly and not spread along the length of the cable.
In this test, a sample is exposed to a variety of aerospace fluids. The duration and temperature of the exposure varies and is defined by the selected test standard.
This test evaluates the ability of a wire or cable to withstand extended exposure to hot water while connected to a relatively low voltage source.
This method is intended for use in determining the effect of oil on oil-resisting insulation and sheath of insulated wire and cable. The procedure may be used for determining the resistance of insulation and sheath to oil at any desired temperature. The tensile strength and elongation, or other characteristic used for determining the degree of deterioration is determined immediately after exposure of the material.
In the resistance to ozone test, a sample is placed in a heated enclosure with an atmosphere containing a prescribed amount of ozone; typically the ozone count is in the parts per billion range. After the exposure, the sample is removed and visually inspected for cracks. For a sample to 'pass' the test, no insulation cracks should be detected during the post-exposure visual inspection.
In the resistance to pinch test, the specimen is placed perpendicularly across a steel rod then compressed under an anvil. The force on the specimen is slowly increased until the insulation is breached and a conductive path is formed between the specimen's conductor and the test apparatus. The pass/fail criteria are product specific.
The purpose of a diode in an electrical circuit is to ensure that current is only allowed to flow in the correct direction. In other words, it acts as a conductor in one direction and as an insulator in the other. The reverse current leakage test evaluates this function by applying a reverse-biased voltage to the sample and measuring for any reverse current.
This test measures the ability of a high frequency connector to withstand a specified RF voltage and frequency.
Safety wires are responsible for maintaining the position of a cable/ wire harness on an aircraft and must be able to endure forces due to turbulence or repeated maintenance. This test evaluates the ability of a connector to withstand pulling forces from a safety wire at the location of the safety wire hole.
This test assesses the wire/cable's insulation durability to sharp edges at ambient temperature. The sample is abraded until there is electrical conductivity between the scrape abrasion jig and sample under test.
This test assesses the wire/cable's insulation durability to sharp edges at eleveated temperature. The sample is abraded until there is electrical conductivity between the scrape abrasion jig and sample under test.
This test evaluates the quality of a sealing component part. This test may identify defects in the sealing material or due to the manufacturing process used to form the seal.
The Seamless or Smooth Surface Verification test is a process control test used to ensure that smooth wrapped tape insulation has properly annealed without a visible outer edge or observable internal wrapping lines.
Aerospace connectors are expected to withstand regular mating and unmating during maintenance, component replacement, etc. It is important that a connector be adequately secured when in use, but not so tightly mated as to hinder the ability to unmate for maintenance. The shell spring finger force test evaluates the force required to engage and separate two mated connectors.
This test measures the resistance between each grounding contact and the shell of a connector. This quality is imperative to the functionality of the connector as current leakage between contacts and the shell can lead to severe malfunction.
For several applications, it is necessary to have a conductive connector shell. For example, harnesses that contain EMI sensitive circuitry are typically shielded and need good grounding and EMI protection as the signals pass through connectors.
Shield coverage is determined by a mathematical formula as defined in AS85485 dependent on the physical properties of the cable shield.
The smoke resistance test places a high current through the wire/cable to determines if the insulation/jacket will produce smoke. The current is increase on the specimen until the conductor temperature reaches the rated insulation temperature.
The Solder Contacts test as defined in MIL-DTL-26482 follows the procedure of a Solderability test in accordance with MIL-STD-202 but with a few different requirements.
This test is used to generate data for comparison between cable specimens using the same stiffness and springback apparatus. Stiffness and springback affect harness manufacturing, harness and cable installation, and maintenance operations.
The strip force test quantitatively evaluates the ease of removing insulation from a finished wire sample. It is important in any electrical system that wire insulation be adherent enough to the conductor to maintain structural integrity and non-adherent enough such that a standard wire stripping tool may readily remove insulation as needed.
The purpose of this test is to measure the level of difficulty to remove the insulation from the conductor. The insulation should not be easily removed from the conductor however should be able to be removed with the usage of a proper insulation removal tool.
The purpose of this test is to measure the resistance of the outer surface of the insulation in a high humidity environment. This is to ensure that the resistance along the outer surface is large enough to prevent leakage current between connections.
This is an examination to ensure that after temperature changes connectors do not display signs of peeling, blistering, flaking, and separation of plating or other damage detrimental to the operation of the connector.
This method is intended for use in determining the tensile strength and percentage elongation at break of conductors
This method is intended for use in determining the tensile stress of insulation and sheath compounds. It is applicable to the usual grades of rubber and thermoplastic compounds used for insulation and sheaths.
The thermal endurance (or high temperature endurance) test determines the ability of the insulation of a firezone or similar wire to resist degradation due to exposure to high temperature.
The thermal index test (also known as the Relative Thermal Life and Temperature Index) is based on multiple cycles of elevated temperature exposure, mechanical stressing, and electrical insulation integrity checks. The goal of this test is to determine the maximum continuous operational temperature for the wire/cable for a targeted time interval (the common goal for aerospace wires is to find the maximum continuous temperature for 10,000 hours of operation). This is achieved with long-term exposure to temperatures above this desired temperature rating.
Temperature cycling can cause rapid degradation of wire/cable insulation integrity. This can manifest and insulation splits, cracks, and/or delamination. Often an overlooked test method for assessment, the thermal shock test proves and excellent means of assessing the construction quality of a wire or cable.
The thermal shock test is applicable to hermetically sealed connectors. The connector undergoes successive cycles consisting of times submersed in hot and cold water baths. After cycling is complete the connectors are dried in a forced air oven, and to pass the examination, the connector must have sustained no damage detrimental to the operation of the connector.
The purpose of the time/current to smoke test is to determine the time (and electrical current) necessary for a wire specimen to produce smoke. The pass/fail criteria for this test is based on the particular wire/cable specification but is typically based on the specimen able to sustain an electrical current level (e.g. 15A) without producing visible smoke.
The tinning test evaluates the ability of the tin layer over a copper conductor to protect the inner conductor from chemical degradation.
In this test, the polyamide (or modified polyamide) topcoat of a sample wire is exposed to boiling water vapor and visually examined for cracking.
On aircraft, cables can be exposed to straining conditions that cause the cable to loose its electrical integrity and damage to insulation. This test assesses the effects of this longtime exposure to straining conditions.
Transfer impedance is the measurement of the current flowing on a shield surface to the voltage developed on the opposite side of the surface. Cable shields are designed to reduce transfer impedance, thus increasing shield effectiveness.
A capacitance unbalance bridge is used to measure the pair-to-ground capacitance of a wire pair inside of a multi-pair cable.
This test evaluates the radial shrinkage of a heat shrink insulation sample to ensure the insulation shrinks to the appropriate dimensions as identified in the detail specification.
The velocity of propagation (also known as the Phase Velocity) test measures the speed of electrical signal transmission down a wire/cable. The velocity of signal propagation is typically represented as a fraction of the speed of light in a vacuum and is primarily impacted by the wire/cable dielectric.
In general, a visual inspection can be used to determine any cracks, conductor exposure and wire degradation which are good indicators for determining the electrical integrity of a wire specimen or cable.
DC resistance measurements and voltage drop calculations are conducted on insulated wires to determine the voltage drop across crimp joints and on re-terminated insulated wires. This evaluation is an effective means of determining the electrical efficacy of a crimp.
This test is typically run as part of posttest assessment procedures to evaluate the sample's insulation/jacket integrity after an environmental or other tests.
Return Loss is a relative measurement of the reflected signal on a cable. In an ideal system, no signal would be reflected, all of the power on a signal would be received by the load, and the return loss would be infinite. In real-life applications, there will always be at least some amount of the input signal reflected back on the cable.
Connectors that are designed to resist pressure and leakage due to water exposure must be capable of doing so over an extended duration. The water pressure test is performed by submerging a number of connector samples in six feet of tap water for a period of 48 hours.
This test is performed on cables intended for routing through watertight bulkheads. Such cables must be particularly resistant to longitudinal water flow to prevent potential damage to internal systems.
The weathering resistance test exposes wire specimens to UV light and condensation and evaluates for any effects on the insulation.
The weight assessment test is used as a test to determine if the final cable weight it within the range listed in the product specification.
This test is used to evaluate the amount of weight lost, if any, from a wire specimen when exposed to temperature and vacuum for a period of several days.
The wet arc-resistance test for wire insulation provides an assessment of the ability of an insulation to prevent damage in an electrical arc environment.
The wet arc-resistance test for wire insulation provides an assessment of the ability of an insulation to prevent damage in an electrical arc environment.
The Wet Short Circuit Test is the European Standard methodology of wet arc track resistance testing. The test identifies the general electrical arcing characteristics of a small harness of wires in contact with a general contaminant.
The wicking test focuses on the wire insulation's propensity for drawing fluids into the insulation.
Insulation color is often used to identify a wire or cable’s system or function(s). This test evaluates the characteristics of an insulator's color as compared to the limitations specified in the applicable standard.
A test sample wire is strung horizontally such that it hangs without resting on any surface. A current 2.5 times that of the "free air rated current" is applied to the sample via a DC power source. The sample is held at this constant current until a current interruption (open circuit) occurs with a maximum allowable time of five minutes. The time to open circuit, if under five minutes, is the reported test result.
It is important that wires involved in a large EWIS system be easily and uniformly identifiable by the manufacturer's markings. This test entails a visual examination of the identification markings on a wire sample.
Knowing the weight of every component on an aircraft, down to the last wire, is vital to good design. This test is to be used to evaluate the weight of a finished wire specimen, it may also be applied to uninsulated conductor for certain standards.
The wrap back examines a wire/cable's insulation susceptibility to breach when tightly wrapped around itself and exposed to elevated temperatures. This test is usually required in the individual wire specifications as part of the insulation integrity assessment. After the elevated temperature exposure, the specimen is visually examined for any insulation cracks (or delamination in the case of tape wrapped insulations). The insulation integrity is then examined with a wet dielectric test.
This test is used to evaluate the quality of insulation and its ability to withstand wrinkling. Wrinkles can occur to insulation when bent back and forth frequently, eventually causing the insulation to deteriorate.