The Insulation Resistance Tester Can Be Used To Measure The Resistance Value Of Various Insulating Materials And The Insulation Resistance Of Transformers, Motors, Cables, Electrical Equipment, Etc. Below We Will Discuss Some Common Problems.
01
What Does The Output Short-Circuit Current Of The Insulation Resistance Tester Mean?
Long Cables, Motors With More Windings, Transformers, Etc. Are Classified As Capacitive Loads. When Measuring The Resistance Of Such Objects, The Output Short-Circuit Current Of The Insulation Resistance Tester Can Reflect The Internal Resistance Of The Internal Output High-Voltage Source Of The Megger. .
02
Why Use The External “G” End To Measure Higher Resistance
The “G” Terminal (Shielding Terminal) Of The Exterior, Its Function Is To Remove The Influence Of Humidity And Dirt In The Test Environment On The Measurement Results. When Measuring Higher Resistance, If You Find That The Results Are Difficult To Stabilize, You Can Consider Using The G Terminal To Eliminate Errors.
03
In Addition To Measuring Resistance, Why Should We Measure Absorption Ratio And Polarization Index?
In The Insulation Test, The Insulation Resistance Value At A Certain Moment Cannot Fully Reflect The Pros And Cons Of The Insulation Function Of The Test Sample. On The One Hand, Due To The Insulation Material Of The Same Function, The Insulation Resistance Appears When The Volume Is Large, And The Insulation Resistance Appears When The Volume Is Small. Big. On The Other Hand, The Insulating Material Has The Charge Absorption Ratio (DAR) Process And Polarization (PI) Process After Applying High Voltage.
04
Why Can Electronic Insulation Resistance Tester Produce Higher DC High Voltage
According To The Principle Of DC Conversion, An Electronic Insulation Resistance Tester Powered By Several Batteries Is Processed By A Booster Circuit. The Lower Power Supply Voltage Will Be Increased To A Higher Output DC Voltage. The High Voltage Generated Is Higher But The Output Power Is Lower.
Precautions For The Use Of Insulation Resistance Tester
1. Before Measuring, Perform An Open Circuit And Short Circuit Test On The Insulation Resistance Tester To Check Whether The Insulation Resistance Tester Is Normal. The Specific Operation Is: Open The Two Connecting Wires, The Pointer Of The Swing Handle Should Point To Infinity, And Then Short The Two Connecting Wires, The Pointer Should Point To Zero.
2. The Device Under Test Must Be Disconnected From Other Power Sources. After The Measurement Is Completed, The Device Under Test Must Be Fully Discharged (About 2~3 Minutes) To Protect The Equipment And Personal Safety.
3. The Insulation Resistance Tester And The Device Under Test Should Be Separated And Connected Separately By A Single Wire, And The Surface Of The Circuit Should Be Kept Clean And Dry To Avoid Errors Caused By Poor Insulation Between The Wires.
4. During The Shaking Test, Place The Insulation Resistance Tester In A Horizontal Position, And No Short Circuit Between The Terminal Buttons Is Allowed When The Handle Is Rolling. When Testing Capacitors And Cables, It Is Necessary To Disconnect The Wiring When The Crank Handle Is Rolling, Otherwise The Reverse Charging Will Damage The Insulation Resistance Tester.
5. When Swinging The Handle, It Should Be Slower And Faster, And Evenly Accelerate To 120r/Min, And Pay Attention To Prevent Electric Shock. During The Swing Process, When The Pointer Has Reached Zero, It Can No Longer Continue To Swing To Prevent Heating And Damage To The Coil In The Watch.
6. In Order To Prevent The Leakage Resistance Of The Device Under Test, When Using An Insulation Resistance Tester, The Intermediate Layer Of The Device Under Test (Such As The Inner Insulation Between The Cable Shell Core) Should Be Connected To The Protective Ring.
7. The Appropriate Insulation Resistance Tester Should Be Selected Depending On The Voltage Level Of The Equipment Under Test. Generally, For Equipment With A Rated Voltage Below 500 Volts, Choose An Insulation Resistance Tester Of 500 Volts Or 1000 Volts; For Equipment With A Rated Voltage Of 500 Volts And Above, Choose An Insulation Resistance Tester Of 1000 To 2500 Volts. In The Selection Of The Range Scale, Care Should Be Taken Not To Make The Measurement Scale Excessively Exceed The Insulation Resistance Value Of The Equipment Under Test To Avoid Large Errors In The Readings.
8. Prevent The Use Of Insulation Resistance Testers To Measure In Lightning Weather Or Nearby Equipment With High-Voltage Conductors.
Post time: Feb-06-2021
