Friday 29 October 2010
Tuesday 3 August 2010
Measuring bonding resistance in aircraft frames
Measuring bonding resistance in aircraft frames
Any electrically operated equipment used on aircraft as well as the bonding resistance of the frame itself, has to be checked regularly to ensure safety is not compromised.
So, the ability to make accurate and reliable measurements is crucial but with the values involved usually very low - often down to milliohms - the key requirement is to understand and eliminate potential sources of error from the measurement process.
To achieve this Cropico, the specialist supplier of precision measurement equipment, offers a range of advanced, precision instruments capable of meeting the demanding requirements of the aircraft industry.
The Cropico Series 4000 digital ohmmeter range provides a practical solution for a wide range of low resistance measurement applications.
The portable and rugged instrument includes a number of advanced features to ensure measurement accuracy including forward and reverse current measurement with auto averaging, true current zero, long scale length and a selectable measurement range from 40m ohms to 4k ohms with respective resolutions between 10 micro ohms and 1 ohm.
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 +800ºC 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.
Cropico are industry leading manufacturers of thermocouples, temperature sensors & temperature measurement devices.
Any electrically operated equipment used on aircraft as well as the bonding resistance of the frame itself, has to be checked regularly to ensure safety is not compromised.
So, the ability to make accurate and reliable measurements is crucial but with the values involved usually very low - often down to milliohms - the key requirement is to understand and eliminate potential sources of error from the measurement process.
To achieve this Cropico, the specialist supplier of precision measurement equipment, offers a range of advanced, precision instruments capable of meeting the demanding requirements of the aircraft industry.
The Cropico Series 4000 digital ohmmeter range provides a practical solution for a wide range of low resistance measurement applications.
The portable and rugged instrument includes a number of advanced features to ensure measurement accuracy including forward and reverse current measurement with auto averaging, true current zero, long scale length and a selectable measurement range from 40m ohms to 4k ohms with respective resolutions between 10 micro ohms and 1 ohm.
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 +800ºC 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.
Cropico are industry leading manufacturers of thermocouples, temperature sensors & temperature measurement devices.
Monday 19 July 2010
Temperature Indicators Launched by Cropico
Cropico has launched the 3000 series of portable, high-accuracy digital temperature indicators that features three units, all with one milli-Kelvin resultion for real-time displays. The series, designed for precision temperature measurement in a range of electronics, industrial, scientific and environmental monitoring applications, comes with a choice of inputs for platinum resistance digital thermometers and all popular thermocouple types.
The Cropico 3000 has inputs for Pt25 and Pt100 platinum resistance thermometers and thermocouples. The 3001 offers the same flexibility but does not include the PT25 input option, while the 3002 is designed for use with Pt100 platinum resistance thermometers only.
The Cropico 3000 has inputs for Pt25 and Pt100 platinum resistance thermometers and thermocouples. The 3001 offers the same flexibility but does not include the PT25 input option, while the 3002 is designed for use with Pt100 platinum resistance thermometers only.
Thursday 15 July 2010
Self Heating Thermometers - Resistance Measurement
Self-heating Thermometers
This effect can be minimised by using a large sensor element that is in good thermal contact with its measurement environment, while allowing sufficient time for the temperature to stabilise. An alternative is to use a short measurement pulse of current thus minimising the heating effect. A good thermometer may be configured to measure with either a continuous or a short current pulse ensuring that the best possible measurement is made.
Resistance Measurement
To measure the resistance of the temperature detector, a current must be passed through the device - typically a current 1mA to 5mA. A source current of 1mA flowing through the 100Ω resistance will generate 100μW of heat. If the sensor element is unable to dissipate this heat it will indicate an artificially high temperature.This effect can be minimised by using a large sensor element that is in good thermal contact with its measurement environment, while allowing sufficient time for the temperature to stabilise. An alternative is to use a short measurement pulse of current thus minimising the heating effect. A good thermometer may be configured to measure with either a continuous or a short current pulse ensuring that the best possible measurement is made.
Tuesday 29 June 2010
D07 Plus - Accurate Low Resistance Measurement
Electric review has posted an article on the latest offering from Cropico, here is an excerpt with a link to the full article at the end of the post.
The Digital Ohmmeter D07Plus from Cropico, a specialist supplier of precision measurement
equipment, improves the accuracy to which low resistance can be measured.
Adding to the popular Cropico digital micro ohmmeter range, the versatile, rugged and easy-to-use D07Plus simplifies resistance associated with electrical connections, weld integrity, cable and joint resistance, electric motors and other engineering applications.
Read full article here.Useful Links
Digital Thermometers, Temperature Measurement & Resistance Measurement from Cropico
Wednesday 23 June 2010
What is an Ohmmeter?
An ohmmeter is a piece of electrical test equipment designed to measure electrical resistance, the opposite of electrical current (for that we use current meters).
There are two types of ohmmeter:
R= V / I
Therefore Resistance is equal to voltage divided by a constant current (I) which is provided by the ohmmeter itself.
For high precision measurements the above types of meter an inadequate. A high precision ohmmeter is required
There are two types of ohmmeter:
- Micro ohmmeter (microhmmeter or microohmmeter) - These make low resistance measurements.
- Megohmmeter (or megaohmmeter) - These devices measure larger resistance values.
R= V / I
Therefore Resistance is equal to voltage divided by a constant current (I) which is provided by the ohmmeter itself.
For high precision measurements the above types of meter an inadequate. A high precision ohmmeter is required
Subscribe to:
Posts (Atom)