Test and Measurement Instruments – their features and functionality

Test and measurement instruments play a vital role in almost all the production as well as development processes. These equipments are not only used to ensure the product quality but also determine the effectiveness of certain processes. Such electrical measuring instruments being developed, are helpful in different ways and are required globally in every place where the signals are generated or analyzed in labs or production.

Following are the features and functionality of few:

1. Insulating Oil Tester: These are in use and consumption since 1960, and have been designed to easily determine the die electric strength of the oils used in switch gears, capacitors, transformers or any other electrical equipment and are considered ideal for laboratory use as well as on-site.Few of the series and model available are:

• AT-100: These are easily operated with an automatic test cycle accompanied by a BDV display. Additionally, they also have an automatic calendar and time running irrespective of the fact if the power is on or off, a built in printer along with a test chamber access interlock.
• US, A, AD, Series: Having test voltage that can be held at any desired level, portable, rugged and with cover and built with one-piece construction with safety interlocked transparent hood covering test cell. These have tests insulating oils to IS, IEC, ASTM, etc.and test voltage to 100kV
• CU Series: These are easy to operate, programmable, even recall and print last 99 test results stored for 100 years even with power off.
• OTSA Series: These are available in Auto and Manual mode, with Large LCD display, built in printer facility, having user Friendly RS 232 Interface, safety protection and accurate performance as few of the key features.

2. Accelerometer: To measure various acceleration forces such as the constant force of gravity or static forces or to measure the vibrations, an electromechanical device, called the accelerometer is used. Few of them works on piezoelectric effect, consisting of microscopic crystal structures which stress due to accelerative forces causing the generation of voltage, and another way to do this is by analyzing the changes in the capacitance.

3. High Voltage Testers: High voltage test equipments (HV detectors) are specially designed for the safe and practical detection of voltages on electrical medium and high voltage systems. It generally used to determince is the electric voltage is present or absent in the device or equipment which is being tested. Various kinds of High Voltage Testers available at Udeyraj include:

a. 5 KV AC Hipot
b. 5 KV AC Hipot, 6 KV DC Hipot along with IR Tester
c. AC DC Hipots
d. DC Hipot Testers DPW Series

These testers have been designed to get measurement of the leakage currents accurately which makes the evaluation of the insulation easier.

4. LCR Meter: An LCR Meter calculates from current, voltage and difference of phase the LCR factors, and measures the inductance, capacitance and the resistance. Their key features include test and voltage current, measured parameters, test frequency.

5. Contact Resistance Testers: These are used in high current cable contacts and in circuit breakers to test the contact resistance. These are mainly used to measure the circuit breaker contact resistance. At Udeyraj, MRL-series is a new generation, fully automatic, 4 terminal line loop contact resistance tester. These have some excellent features like Built-in printer, ability to access stored last 100 test results, front panel with legend and are micro control operated.

6. Oil Tan Delta Tester: These are used in power transformers to measure the tan/delta power factor along with the capacitance of insulation at multiple frequencies and gives a better picture of the insulating oil and also indicate if any contamination is found. OTD-45 at Udeyraj, is a self-contained single unit which consist of a temperature sensor with high frequency of induction heating along with oil test cell, with I-Touch LCD screen and facility of memory storage and recollection of test results along with max output of 2k/l.

7. Circuit breaker analyzer: It uses a Windows based program installed in the laptop or tablet to help determine what the condition is of various types of circuit breakers. It integrates the condition based analysis, vibration analysis along with internet data transfer with an online database to make the testing of circuit breakers easy and hassle free without having to remove the breakers from their position. They have instantaneous opening as well as closing speed, with maximum speed, time-travel characteristics curve

8. Time Interval Meter: It displays time delay or pulse width between individual pulses to a resolution of 0.2 µs and can also display the average time delay or average pulse width between multiple pulses. The UDEY TIM-1 is a precise test set which uses a crystal base of measurements which have the four-digit digital display, portable and light weight with multi-range display feature to 9999 seconds in five different ranges.

9. Auto variable transformer: A variac, or the variable transformer has a similar construction as that of the fixed type. A primary winding is wrapped across a laminated magnetic core which is then used as in the auto transformer, but it is not fixed at any tapping point which is predetermined, instead a carbon brush is used to tap the secondary voltage. Variable transformers can handle only lower voltages even though they are used for similar purposes as regular transformers.

10. Transformer Turns Ratio Meter: It is an automatic transformer ratio tester which is microprocessor based and is designed especially to accurately measure the turn ratios in CVTs also known as the Capacitor Voltage Transformers. UDEY TRM-11 is a fully automatic transformer ratio tester, which measures ratios, ratio errors of single as well as three phase transformers. Operators just need to enter the parameters, and then the device does all the work and displays the result on the LCD screen at the end of the test. They are equipped to carry out automatic calculations of ratio errors, as well as isolate the test voltage after the testing, and provide an option to print 30 previous test results.