A. Product Overview

The Metrix Plus DIT 3125A Eco is a professional digital insulation resistance tester used to evaluate the condition and quality of electrical insulation.

Electrical insulation can deteriorate because of ageing, moisture, contamination, excessive temperature, mechanical damage and prolonged operating stress. An insulation resistance tester helps maintenance professionals identify deterioration by applying a controlled DC test voltage and measuring the resulting insulation resistance.

The DIT 3125A Eco offers four selectable rated test voltages:

• 500V
• 1000V
• 2500V
• 5000V

Its insulation resistance measurement capability extends from 0.0 MΩ up to 1000 GΩ. 

Key Features

• Digital insulation resistance measurement
• Maximum test voltage of 5000V
• Insulation resistance range up to 1000 GΩ
• Polarization Index measurement
• Timer measurement function
• Automatic discharge function
• Live wire warning with audible indication
• Backlit LCD display
• Low voltage indication
• Automatic power off
• Overload protection
• AC and DC voltage measurement from 30V to 600V
• Battery operation
• 12V DC adapter operation
• Portable heavy duty construction 

B. Working Principle

The Metrix Plus DIT 3125A Eco works by applying a controlled high DC voltage across the insulation being tested.

When the selected voltage is applied, a very small current flows through the insulation. The tester measures this current and calculates the insulation resistance according to the relationship:

Resistance = Applied Voltage divided by Leakage Current

Good electrical insulation generally produces a very high resistance value.

If the insulation has deteriorated because of moisture, contamination, ageing or physical damage, more leakage current may flow and the measured insulation resistance can decrease.

Typical Testing Procedure

1. Disconnect and isolate the equipment from its normal electrical supply.

2. Confirm that the equipment is safe for insulation testing.

3. Connect the appropriate test leads.

4. Select the required test voltage.

5. Apply the test voltage.

6. Allow the instrument to measure insulation resistance.

7. Read the resistance value on the LCD.

8. Compare the result with the equipment specification or applicable maintenance criteria.

9. After testing, allow the automatic discharge function to discharge residual electrical energy.

The correct test voltage depends on the equipment, rated voltage and applicable testing procedure.

Polarization Index Measurement

One of the important features of the DIT 3125A Eco is Polarization Index measurement, commonly referred to as PI.

PI testing compares insulation resistance measurements taken at different time intervals during a sustained insulation test. It can provide additional information about insulation condition compared with a single instantaneous resistance reading.

This function is particularly useful for preventive maintenance and condition assessment of larger electrical equipment. 

C. Why Is the Metrix Plus DIT 3125A Eco Used?

1. High Voltage Insulation Resistance Testing

The tester can apply up to 5000V DC, making it suitable for insulation testing applications that require higher test voltages.

2. Motor Insulation Testing

It can be used to evaluate insulation resistance in suitable industrial motors and motor windings.

3. Transformer Insulation Testing

Electrical maintenance teams can use a high voltage insulation tester as part of transformer insulation condition assessment.

4. Cable Insulation Testing

Power and electrical cables can be checked for deterioration, moisture ingress and insulation leakage.

5. Generator Testing

Insulation resistance testing can form part of preventive maintenance programs for generators and associated windings.

6. Electrical Panel Maintenance

The tester can assist technicians during maintenance and commissioning of suitable electrical panels and circuits.

7. Preventive Maintenance

Periodic insulation testing can reveal changes in insulation resistance before they develop into major equipment failures.

8. Polarization Index Testing

PI measurement provides an additional method of evaluating insulation condition over time.

9. AC and DC Voltage Measurement

The DIT 3125A Eco can measure AC and DC voltage from 30V to 600V, allowing technicians to perform an additional voltage check using the same instrument. 

10. Field and Workshop Testing

The ability to operate using either batteries or a 12V DC adapter makes the instrument useful for both field inspection and workshop applications. 

D. Suitable Buyers

The Metrix Plus DIT 3125A Eco 5 kV Digital Insulation Tester is suitable for:

• Electrical engineers
• Electrical maintenance technicians
• Industrial maintenance departments
• Electrical contractors
• Transformer maintenance companies
• Motor maintenance companies
• Motor rewinding workshops
• Power generation companies
• Power distribution companies
• Electrical testing companies
• Cable installation contractors
• Manufacturing plants
• Preventive maintenance contractors
• Control panel manufacturers
• Electrical commissioning engineers
• Facility maintenance departments
• Engineering companies
• Testing laboratories
• Generator service companies
• Industrial electrical service providers
• Electrical inspection agencies

It is particularly suitable for professionals who need high voltage insulation resistance testing up to 5 kV and high resistance measurement up to 1 TΩ.

Frequently Asked Questions

1. What is the Metrix Plus DIT 3125A Eco?

The Metrix Plus DIT 3125A Eco is a digital insulation resistance tester designed for high voltage insulation testing up to 5000V and resistance measurement up to 1000 GΩ. 

2. What test voltages are available?

The tester provides:

• 500V
• 1000V
• 2500V
• 5000V 

3. What is the maximum insulation resistance measurement?

The maximum specified insulation resistance range is 1000 GΩ, equivalent to 1 TΩ. 

4. Is the DIT 3125A Eco a 5 kV insulation tester?

Yes. Its highest rated insulation test voltage is 5000V or 5 kV.

5. Can the DIT 3125A Eco be called a digital megger?

Yes. In common electrical industry terminology, digital insulation resistance testers are often referred to as digital meggers.

6. Does it support Polarization Index measurement?

Yes. PI measurement is one of the specified functions of the DIT 3125A Eco. 

7. What is Polarization Index?

Polarization Index is a time based insulation assessment method that compares insulation resistance measurements taken at different intervals during a sustained test.

8. Does it have a timer function?

Yes. The DIT 3125A Eco includes a timer measurement function for performing measurements over a selected period. 

9. Does the tester have automatic discharge?

Yes. The DIT 3125A Eco includes an automatic discharge function after insulation testing. 

10. Why is automatic discharge important?

High voltage insulation testing can leave stored electrical energy in the equipment under test. The discharge function helps reduce residual charge after testing.

11. Does the DIT 3125A Eco have a live circuit warning?

Yes. It includes a live wire warning system with audible indication. 

12. Can it measure AC voltage?

Yes. The specified voltage measurement range is 30V to 600V AC and DC. 

13. Can it measure DC voltage?

Yes. DC voltage measurement from 30V to 600V is supported.

14. What is the voltage measurement resolution?

The specified voltage resolution is 1V. 

15. What is the short circuit current?

The specified maximum short circuit current is approximately 1.3 mA.