Improved testing of earth bonding connections between fuel tanks and airframe sections is provided by the DO4000 range of high performance, digital milliohmmeters now available from Cropico.
The portable and rugged instrument includes several advanced features to check the integrity of earth connections within an aircraft’s body as an integral part of an advanced quality control programme.
The DO4000 can also be a key feature of maintenance programmes designed to identify and reduce the potential for airframe corrosion on front line fighter aircraft. Technicians can utilise the instrument to measure the ground points on a range of civilian and military aircraft and helicopters.
These ground points are located at various key points around the airframe and the DO4000 enables technicians to quickly and easily check that the resistance levels between each one are lower than <2.5milliOhm.
Ground points are required to create a safe electrical network inside an aircraft - when it flies through dry air it gets statically charged, so when it lands this needs to be safely discharged through the ground.
Features of the DO4000 include forward and reverse current measurement with auto averaging, true current zero, long scale length and a selectable measurement range from 40Ω to 4kΩ with respective resolutions between 10µΩ and 1Ω.
Within the range, model 4001 also includes temperature compensation, with preset coefficients for copper and aluminium plus user settable coefficients for other materials. Temperature measurement over the range -50 to +800°C is also available.
Protection up to 415V rms is provided at the measurement terminals and push button operation is achieved easily by clearly marked function controls. Direct reading measured values are displayed on a four-digit LCD display.
Over range and low battery indication is also provided and warning LEDs illuminate when an open circuit lead condition is detected. The 4000 series can be supplied with a rechargeable battery option featuring a battery pack, docking station and charger.