ANENG MH13 Megohmmeter Ohm Tester

1. Introduction

The ANENG MH13 Megohmmeter Ohm Tester is a specialized instrument designed for measuring insulation resistance. It serves as an ideal test tool for assessing the insulation resistance of large transformers, generators, high-voltage motors, power capacitors, cables, and arresters. This digital multimeter offers a 2000-count display and includes advanced features such as Polarization Index (PI) and Absorption Ratio (DAR) measurements, along with 100 sets of data storage.

2. Safety Requirements & Warnings

Always read this manual thoroughly before use and follow all instructions to ensure safe operation.

Safety Symbol Description:

• Caution: Refer to the user's manual before using this meter. Double Insulation.
• Warning: Dangerous Voltage (Risk of electric shock).
• Danger: To avoid serious or fatal damage that may be caused by certain states and wrong operations.

General Precautions:

• Do not use accessories not provided by the original factory.
• During testing, a DC high voltage output is present on the measuring terminals E and L. Avoid touching them to prevent electric shock.
• To prevent errors from test lead insulation leakage, suspend the test rod connected to the 'L' end, avoiding contact with external objects or the 'E' end wire.
• If the measured object's insulation resistance is high and shows serious 'word jumping' (fluctuation), connect the instrument's 'G' (shield) terminal to the cable shell to eliminate measurement errors due to surface leakage.
• After testing, disconnect all connecting wires.
• Do not use or store the instrument in direct sunlight, high temperature, or high humidity.
• The measuring end should not be short-circuited for more than 60 seconds.
• Continuous working time should not exceed 30 minutes.
• If the instrument is abnormal (e.g., broken casing, exposed metal parts), discontinue use immediately.
• Do not press function buttons while test leads are connected to a live circuit; first exit measurement, then change the item.
• Do not install substitute parts or make unauthorized changes.
• Do not replace the battery when the instrument is wet.
• Ensure all test leads are securely connected.
• Turn off the instrument before opening the battery cover.
• Before measuring, confirm the correct function button is selected.
• After use, press and hold the 'OFF' button to turn off the unit. Remove batteries for long-term storage.
• Clean the instrument case with a damp cloth or detergent; do not use abrasives or solvents. Dry thoroughly if wet before storage.

3. Package Contents

The ANENG MH13 Megohmmeter Ohm Tester package includes the following items:

• Insulation Resistance Tester (ANENG MH13)
• Instruction Manual
• Storage Bag
• Alligator Clips
• Test Leads (Red and Black)
• Signal Shielding Wire
• Packaging Box

4. Specifications

The following tables detail the technical parameters of the ANENG MH13 Megohmmeter Ohm Tester:

General Specifications:

• Max Count: 2000 counts
• Display Type: Analogue and Digital (HD backlit screen)
• Battery: 8 x AA5 (1.5V) batteries (included)
• Material: Silica gel/ABS
• Weight: 640g
• Pen Material: PVC/Brass
• Overall Length of Test Leads: 108cm
• Features: Back support, Low voltage indication, Absorption ratio, Polarization Index, Autoranging, Automatic discharge, Test voltage display, High pressure indication, Measurement time display.
• Data Storage: 100 sets
• Operating Temperature: 0~40 ℃
• Working Conditions: 0°C~35°C, relative humidity ≤ 75%, altitude ≤ 2000 meters.
• Withstand Voltage: AC 2KV 50Hz for 1 minute.
• Low Battery Indication: Display shows 'E3' symbol.
• Certification: CE

Technical Data Tables:

5. Controls and Display

The ANENG MH13 features an intuitive layout for easy operation. Refer to the diagram below for button and terminal identification:

Key Components:

• Output Voltage Terminals: 250V-2500V (Square symbol)
• AC/DC Voltage Terminals: AC/DC 600V (LINE), MAX 600V, EARTH G, AC/DC 10V-600V
• Insulation Resistance Terminals: LINE (L), EARTH (G), Sampling Jack (E)
• Display: LCD screen with 2000 counts, bar graph, and backlight. Shows measurement values, units (MΩ, GΩ, V), time (min, sec), PI, DAR, MEM, READ, HOLD, CLR, FUL, low battery indicator.

Button Functions:

• TEST: Initiates insulation resistance test. Red warning light indicates high voltage output. Also functions as a discharge button.
• ▲ (Up Range / Page Up): Increases range or navigates up in stored data.
• ▼ (Decrease Range / Page Down): Decreases range or navigates down in stored data.
• HOLD*: Single press to hold current data. Long press to turn backlight on/off.
• SELECT: Function switch button to cycle between Insulation Resistance, AC Voltage, and DC Voltage modes.
• MEM READ: Used for data storage and viewing stored data.
• PI/DAR: Switches between Absorption Ratio (DAR) and Polarization Index (PI) measurement modes. Automatically computes DAR/PI.
• Power Button (Red): Press and hold for 2 seconds to power the unit on or off.

6. Setup

6.1 Battery Installation

1. Ensure the device is powered off and test leads are disconnected.
2. Locate the battery compartment on the back of the device.
3. Unscrew and remove the battery cover.
4. Insert 8 AA (1.5V) batteries, paying close attention to the positive (+) and negative (-) indicators inside the compartment to ensure correct polarity.
5. Replace the battery cover and secure it with the screw.

6.2 Test Lead Connection

• Plug the red test lead into the 'L' (LINE) input jack of the meter.
• Plug the black test lead into the 'E' (EARTH) input jack of the meter.
• For measurements requiring a shielded connection (e.g., to avoid surface leakage errors with high insulation resistance), connect the signal shielding wire to the 'G' (EARTH) port.

7. Operating Instructions

7.1 Power On/Off

• To power on, press and hold the red power button for more than 2 seconds.
• To power off, press and hold the red power button for more than 2 seconds.

7.2 Insulation Resistance Measurement

1. Power on the device. It will default to insulation resistance measurement mode, displaying "---".
2. Use the ▲ and ▼ buttons to select the appropriate output voltage (e.g., 50V, 100V, 250V, 500V, 1000V, 2000V, 2500V, 5000V). The selected voltage will appear in the lower right corner of the display.
3. Connect the test leads to the two ends of the object under test. Ensure the test rod connected to 'L' is suspended if possible to avoid leakage errors.
4. Press the TEST button. The red warning light on the button will illuminate, indicating high voltage output. The insulation resistance value will be displayed in the middle of the screen, and the measurement time on the bottom left.
5. To stop the measurement, press the TEST button again. The test light will turn off, and the measured value will remain on the display.
6. Note: Before testing, ensure the circuit under test is de-energized. Do not measure live equipment. After measurement, do not touch the circuit with bare hands due to stored capacitance.

7.3 DC Voltage Test

1. From the standby interface, short press the SELECT button to enter the AC voltage function and press it again to switch to the DC voltage function. The display will show "DC" and "V".
2. Insert the red test lead into the "AC/DC 600V" jack and the black test lead into the "G" input jack.
3. Touch the two test leads to the two ends of the voltage to be measured. The measured DC voltage in volts will be displayed.
4. Note: The measured voltage should not exceed 600V DC.

7.4 AC Voltage Test

1. From the standby interface, short press the SELECT button to enter the AC voltage function. The display will show "AC" and "V".
2. Insert the red test lead into the "AC/DC 600V" jack and the black test lead into the "G" input jack.
3. Touch the two test leads to the two ends of the voltage to be measured. The measured AC voltage in volts will be displayed.
4. Note: The measured voltage should not exceed 600V AC (RMS) and the frequency should be between 40Hz and 70Hz. Measurements outside this range may have reduced accuracy.

7.5 Absorption Ratio (DAR) Measurement

The DAR measurement helps determine if equipment is affected by moisture. It uses the insulation resistance values at 15 seconds and 1 minute.

1. Ensure the insulation resistance measurement is complete (measurement time > 1 minute).
2. Press the PI/DAR button until "DAR" is displayed. The instrument will automatically calculate and display the absorption ratio.
3. DAR Calculation: (1 minute insulation resistance) / (15 seconds insulation resistance).
4. Judgment Standard:
   • ≥1.4: Best
   • 1.25-1.0: Good
   • ≤1.0: Bad

7.6 Polarization Index (PI) Measurement

The PI measurement is crucial for assessing the insulation condition, quality, and aging problems of power systems (transformers, motors, cables, etc.).

1. Ensure the insulation resistance measurement is complete (measurement time > 10 minutes).
2. Press the PI/DAR button until "PI" is displayed. The instrument will automatically calculate and display the polarization index.
3. PI Calculation: (10 minutes insulation resistance) / (1 minute insulation resistance).
4. Judgment Standard:
   • ≥4: Most
   • 4-2: Good
   • 2.0-1.0: Warning
   • ≤1.0: Bad

7.7 Data Hold and Backlight Operation

• Data Hold: Single press the HOLD* button to hold the current data on the display. Press it again to exit data hold.
• Backlight: Long press the HOLD* button for more than 2 seconds to turn the backlight on. Long press again for more than 2 seconds to turn it off.

7.8 Data Storage and Retrieval

• Store Data: After measuring insulation resistance, press HOLD* to hold the data (displaying "HOLD"). Then, press MEM READ to save the data (displaying "MEM"). The instrument can store up to 100 sets of data.
• Read Data: After powering on, press the MEM READ button (displaying "READ"). Use the ▲ and ▼ buttons to scroll through stored data. Long press MEM READ to exit data reading.
• Delete Data: In data reading mode, press the SELECT button to delete the current data (displaying "---"). To delete all stored data, long press the PI/DAR button.

8. Maintenance

8.1 Cleaning

• Use a damp cloth or mild detergent to clean the instrument case.
• Do not use abrasive cleaners or solvents, as these can damage the casing.
• If the instrument becomes wet, dry it thoroughly before use or storage.

8.2 Battery Replacement

If the low battery indicator (E3) is displayed on the LCD, replace the batteries:

1. Turn off the instrument and disconnect all test leads from the meter and the object under test.
2. Unscrew and remove the battery cover from the back of the meter.
3. Remove the old batteries and insert 8 new AA (1.5V) batteries, ensuring correct polarity.
4. Replace the battery cover and secure it with the screw.

Warning: Do not open the battery cover during measurement.

9. Troubleshooting

• Instrument Malfunction: If the instrument is broken or has exposed metal parts, stop using it immediately.
• Short Circuit Indication: During a short circuit test, if the resistance value is less than 0.5 MΩ, it indicates a short circuit.
• Measurement Errors / Word Skipping: If the insulation resistance of the object is high and there is a serious 'word skipping' phenomenon, connect the shielded cable to the 'G' port to avoid measurement errors caused by surface leakage.
• Low Battery: If 'E3' is displayed, replace the batteries as described in Section 8.2.

10. User Tips

• Language of Manual: This manual is provided in English. For instructions in other languages, please check the official ANENG website or contact customer support.
• Unknown Voltage/Current: When measuring an unknown voltage or current, always start with the highest available range to prevent damage to the instrument, then adjust to a more appropriate range for accurate readings.
• Motor Resistance Test: When testing motor resistance, ensure the motor is powered on for a successful connection. A beep indicates a successful connection.

11. Warranty and Support

For warranty information, technical support, or service inquiries, please contact ANENG customer service or your authorized dealer. Please have your product model (MH13) and purchase details available when contacting support.

A PDF version of the user manual may be available for download. Please refer to the official product page or contact support for the link.

Note: Specifications and features are subject to change without prior notice.