UNI-T UT501B - User Manual

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UT501B Insulation Resistance Tester is designed with brand-new

design and combination of massive integrated and digital circuits; it

can measure insulation resistance, low resistance, AC voltage, etc,

and enjoys high degree of accuracy, stable performance, easy

operation and reliability. It is used for insulation resistance

measurement for insulation materials and various kinds of electric

equipments such as transformer, electric machines, cables,

switches, electrical appliances, a ideal tool for electric equipment

maintenance, testing and inspection.

Safety Information

Warning

The tester is designed and manufactured in compliance with

IEC61010 standard. The manual covers safety information related

to the safe operations and conditions of the instrument. please read

carefully before using the instrument.

Use always as specified in the manual, and keep it for future use.

conditions and actions that may cause serious or

fatal damage.

Alerts users to avoid electric shock.

conditions and actions that may cause damage to

the instrument or affect accurate measurement.

voltage over 750VAC.

Eg: the instrument damaged or had exposed metal.

Do not touch the tested line during insulation measurement.

during test.

test leads lead when measuring.

When test leads are shorted and connected to the instrument, do

not press TEST key.

Low Resistance Measurement

Polarization Index/Dielectric Absorption Ratio Measurement

PI Measurement

PI Value

DAR Measurement

DAR Value

Shorted Current

Rated current

Insulation Resistance Measurement

Accuracy: ±( a% of reading + b digits ), calibration per year.

Electrical Symbols

Risk of electric shock

discharged.

between test leads and test ports

resistance measurement.

leads

low battery indicator shows

properly.

Low battery indication:

Overload indication: "＞5.5GΩ" shows under insulation resistance

measurement.

display the unit and function simultaneously

Altitude:

under normal condition.)

operating manual, carrying case.

test leads,

Voltage Measurement

● Automatic voltage release

● Backlight for work in dark sites

● Red light for warning

● Safety compliances: Overvoltage CATIII 600V, Pollution

Degree 2 as per IEC61010

5. Tester's Structure(Front View)

measurement

for insulation resistance measurement

Switch button for PI/DAR

Test button

Rotary knob

LCD Display

1. PI/DAR button: measures polarization index/dielectric absorption

ratio.

2. ZERO/LIGHT button: turns on/off the backlight or resets the

display to zero for low resistance measurement.

3. TEST button: turns on/off insulation and low resistance

measurement.

4. Rotary knob set to ACV: to measure AC voltage.

Buttons and Rotary Knob

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Summary

Safety Information and Precautions

Technical Specifications

Insulation Resistance Measurement Specs

Details specifications for insulation resistance testing, including rated voltage, range, and accuracy.

PI and DAR Measurement Specifications

Provides specifications for Polarization Index (PI) and Dielectric Absorption Ratio (DAR) measurements.

Low Resistance Measurement Specifications

Details specifications for low resistance measurements, including voltage, range, resolution, and accuracy.

AC Voltage Measurement Specifications

Details specifications for AC voltage measurement, including range, resolution, and accuracy.

Buttons and Rotary Knob Functions

PI;DAR Button Functionality

Explains the function of the PI/DAR button for measuring polarization index and dielectric absorption ratio.

ZERO;LIGHT Button Functionality

Details the ZERO/LIGHT button for backlight control and zero reset in low resistance mode.

TEST Button Functionality

Describes the TEST button for initiating insulation and low resistance measurements.

Rotary Knob for AC Voltage Measurement

Explains setting the rotary knob to ACV for AC voltage measurement.

Rotary Knob Settings for Measurement

Rotary Knob for Continuity Measurement

Instructions for setting the rotary knob to CONTINUITY for low resistance measurement.

Rotary Knob for Insulation Test Voltages

Instructions for selecting test voltages (250V/500V/1000V) using the rotary knob.

Preparations Before Measurement

AC Voltage Measurement Procedure

Low Resistance Measurement Procedure

Insulation Resistance Measurement Procedure

Continuous Measurement Mode

Explains how to perform continuous insulation resistance measurements using the TEST button lock.

Polarization Index Measurement

Guide for performing Polarization Index (PI) measurements using the PI/DAR button and TEST button.

Dielectric Absorption Ratio Measurement

Guide for performing Dielectric Absorption Ratio (DAR) measurements using the PI/DAR button.

Summary

Safety Information and Precautions

Technical Specifications

Insulation Resistance Measurement Specs

Details specifications for insulation resistance testing, including rated voltage, range, and accuracy.

PI and DAR Measurement Specifications

Provides specifications for Polarization Index (PI) and Dielectric Absorption Ratio (DAR) measurements.

Low Resistance Measurement Specifications

Details specifications for low resistance measurements, including voltage, range, resolution, and accuracy.

AC Voltage Measurement Specifications

Details specifications for AC voltage measurement, including range, resolution, and accuracy.

Buttons and Rotary Knob Functions

PI;DAR Button Functionality

Explains the function of the PI/DAR button for measuring polarization index and dielectric absorption ratio.

ZERO;LIGHT Button Functionality

Details the ZERO/LIGHT button for backlight control and zero reset in low resistance mode.

TEST Button Functionality

Describes the TEST button for initiating insulation and low resistance measurements.

Rotary Knob for AC Voltage Measurement

Explains setting the rotary knob to ACV for AC voltage measurement.

Rotary Knob Settings for Measurement

Rotary Knob for Continuity Measurement

Instructions for setting the rotary knob to CONTINUITY for low resistance measurement.

Rotary Knob for Insulation Test Voltages

Instructions for selecting test voltages (250V/500V/1000V) using the rotary knob.

Preparations Before Measurement

AC Voltage Measurement Procedure

Low Resistance Measurement Procedure

Insulation Resistance Measurement Procedure

Continuous Measurement Mode

Explains how to perform continuous insulation resistance measurements using the TEST button lock.

Polarization Index Measurement

Guide for performing Polarization Index (PI) measurements using the PI/DAR button and TEST button.

Dielectric Absorption Ratio Measurement

Guide for performing Dielectric Absorption Ratio (DAR) measurements using the PI/DAR button.

The UNI-T UT501B is an insulation resistance tester designed for measuring insulation resistance, low resistance, and AC voltage. It combines massive integrated and digital circuits to deliver high accuracy, stable performance, and ease of operation. This device is an ideal tool for the maintenance, testing, and inspection of electrical equipment, including transformers, electric machines, cables, switches, and appliances.

Function Description

The UT501B offers multiple measurement capabilities:

Insulation Resistance Measurement: This is the primary function, allowing users to assess the integrity of insulation materials in various electrical systems. The device provides selectable test voltages (250V, 500V, 1000V) to accommodate different testing requirements.
Low Resistance Measurement: In addition to insulation, the UT501B can measure low resistance, which is crucial for checking continuity and the resistance of conductors.
AC Voltage Measurement: The tester can also measure AC voltage, providing a versatile diagnostic tool for electrical systems.
Polarization Index (PI) Measurement: The PI function helps evaluate the long-term health of insulation by comparing insulation resistance at different time intervals (10 minutes vs. 1 minute). A higher PI value generally indicates better insulation quality.
Dielectric Absorption Ratio (DAR) Measurement: The DAR function provides another indicator of insulation condition by comparing insulation resistance at shorter time intervals (1 minute vs. 30 seconds or 1 minute vs. 15 seconds). This helps detect moisture or contamination in insulation.

Usage Features

The UT501B is designed with user convenience and safety in mind:

Clear Display: An LCD screen displays measurement readings, units, and function indicators simultaneously. It also features a low battery indicator and an overload indication for readings exceeding the maximum range.
Automatic Ranging: The device automatically selects the appropriate measurement range, simplifying operation.
Automatic Voltage Release: After insulation resistance measurement, the device automatically discharges any stored electrical energy in the circuit under test, enhancing safety.
Backlight: A backlight function allows for operation in dark environments.
Warning Light: A red warning light indicates potentially hazardous conditions during testing.
Rotary Knob and Buttons: The device features a rotary knob for selecting measurement functions (ACV, CONTINUITY, 250V, 500V, 1000V) and dedicated buttons for PI/DAR measurement, backlight/zeroing, and initiating/stopping tests.
Continuous Measurement: For insulation and low resistance measurements, the device can be set to continuous mode, allowing for hands-free testing once initiated.
Safety Precautions: The manual emphasizes critical safety guidelines, such as not measuring circuits with voltage over 750VAC, avoiding flammable environments, not operating with wet hands or surfaces, and ensuring circuits are fully discharged and isolated before resistance measurements. It also warns against touching conductive parts of test leads during measurement and opening the battery cover during operation.
Battery Indication: A low battery indicator prompts users to replace batteries when their voltage drops below 7V, ensuring reliable operation.
Self-Check Function: The UT501B includes an internal 10MΩ resistor for self-checking the accuracy of its measurements, allowing users to verify the device's performance.
Ergonomic Design: The device is designed to be portable and easy to handle, with dimensions of 150mm(L)x100mm(W)x71mm(D) and a weight of 0.7kg (including battery).

Maintenance Features

Proper maintenance ensures the longevity and accuracy of the UT501B:

Battery Replacement: The device uses six 1.5V AA alkaline batteries. The manual provides clear instructions for safe battery replacement, emphasizing the importance of turning off the power, removing test leads, and securing the battery cover afterward. It also warns against mixing new and old batteries or incorrect polarity.
Cleaning: The housing can be cleaned with a soft cloth or sponge dampened with clean water. Users are advised not to submerge the instrument in water and to dry it thoroughly if it gets wet before storage.
Storage: For long-term storage, it is recommended to remove the batteries to prevent leakage. The device should be stored in a dry environment, away from high temperatures, high humidity, flammable, explosive, or strong electromagnetic fields.
Professional Servicing: If the instrument requires verification or repair, it should be delivered to a qualified professional serviceman or designated repairing department.
Test Lead Replacement: If test leads or adaptors are damaged, they should be replaced with components of the same model or electrical specification to maintain safety and performance.

UNI-T UT501B Specifications

General

Type	Insulation Resistance Tester
Test Voltage	100V/250V/500V/1000V
Auto Range	Yes
Low Battery Indication	Yes
Data Hold	Yes
LCD Backlight	Yes
Alarm Light Display	Yes
Alarm Buzzer	Yes
High Voltage Indication	Yes
Over Load Indication	Yes
Auto Discharge	Yes
Power Supply	6x 1.5V AA Batteries
Display	Digital LCD
Safety Standards	CAT III 600V