By hvhipot 
Are you curious about how those massive electrical devices ensure smooth and unobstructed transmission of current without accidents? Behind this, there are some seemingly insignificant ‘heroes’, and the circuit resistance tester is one of them. Today, let’s talk about this’ small device, big effect ‘guy.
What is a circuit resistance tester?
Simply put, a circuit resistance tester is an instrument specifically designed to measure the resistance in electrical circuits. It calculates the total resistance of the circuit based on Ohm’s law (R=U/I) by applying a constant DC current and measuring the resulting voltage drop.
Why is it important? Resistance is the ‘roadblock’ for current transmission. The larger the resistance, the more energy loss, the more severe the heating, and may even cause equipment damage or safety accidents. In the power system, even small resistance anomalies can accumulate into major problems over long periods of operation.
The ‘behind the scenes’ driving force that affects circuit resistance
To accurately measure, it is necessary to understand the factors that affect resistance:
Material and cross-sectional area of conductor: Copper has a lower resistance than aluminum, and the larger the cross-sectional area, the lower the resistance.
Contact point quality: Whether the connection point is oxidized or loose will significantly increase the contact resistance.
Temperature: When the temperature of most conductors increases, the resistance also increases accordingly.
Connection length: The longer the wire, the greater the total resistance naturally.
Intelligent ‘Detective’: Choosing the Right Measurement Tool
HV Hipot Electric Co., Ltd. has developed and produced various high-performance electrical measurement equipment, including advanced circuit resistance testers. They have the characteristics of high accuracy, easy operation, and intuitive data, which can help you quickly locate problems.
How to “pulse” the power circuit?
To measure circuit resistance, the following steps are usually followed:
Select appropriate testing points: Identify key connection points, such as circuit breaker contacts, busbar connections, internal connections of switchgear, etc.
Connect the test line: Connect the current and voltage terminals of the tester to the two ends of the tested circuit.
Start testing: Apply the test current according to the instrument instructions, and the instrument will automatically calculate and display the resistance value.
Analysis results: Compare the measured values with standard values or historical data to determine if there are any abnormalities.
FAQ
Q1: In which scenarios is the circuit resistance tester mainly used? A1: Widely used in power substations, power plants, switch manufacturing plants, industrial enterprises, etc., for measuring the circuit resistance and contact resistance of electrical equipment such as high-voltage switches, transformers, busbars, cables, etc.
Q2: Why does direct current need to be applied to measure circuit resistance? A2: DC current can avoid the influence of inductive reactance in AC current and more accurately reflect the pure resistance characteristics.
Q3: What safety precautions should be taken when measuring? A3: Operators need to wear insulation protective equipment, strictly follow the instrument operating procedures, and ensure a safe testing environment.
Q4: What factors can cause an increase in circuit resistance? A4: Oxidation, corrosion, loose connectors, insufficient cross-sectional area of wires, and excessively long wires can all lead to an increase in resistance.
Q5: How to determine if the circuit resistance is qualified? A5: Compare the measured values with the technical requirements of the equipment, national standards, or historical data of similar equipment. If they exceed the allowable range, they may not be qualified.