The megger insulation tester is essentially a highrange resistance meter ohmmeter with a builtin directcurrent generator. Jan 15, 2021 the measurement of insulation resistance is a common routine test performed on all types of electrical wires and cables. K0019e02 september 2015 construction power, energy, environment service, maintenance insulation resistance measurement of solar panels insulation tester ir4053. Once the measurements are made, the output is turned off. Leaking is measured as leakage current in general and is a result of voltage tension. Insulation resistance testing of low voltage cables in the field. Insulation resistance measurement functions power supply dimensions and mass basic specifications dc v range 4. Battery insulation resistance measurement methods, insulation resistance measurement methods, insulation resistance determination apparatuses, and articles of manufacture are described. Apr 30, 2015 this ti design provides a reference solution to measure insulation resistance up to 100m it has an onboard isolated 500vdc power supply and an isolated signal conditioning circuit to measure the leakage current. The measurement is usually done before the turning on of the pv inverter or at least once or twice per day. An inside look at the reasons for testing, the types of testing available, and the proper test methods for each application. Turn digital multimeter dial to resistance, or ohms, which often shares a spot on the dial with one or more other test measurement modes continuity, capacitance or diode.
The insulation resistance of an insulation is defined as the resistance in megohms offered by the insulation to an impressed direct voltage. Jan 01, 2015 this resistance is often measured by a metering instrument namely as megger. Cable insulation resistance measurements made during. In this example well consider a ceramic capacitor of 2. Tester performs at least 7 insulation tests of v dc into 1m. As an example of this phenomenon, consider an insulation resistance measurement where the effective insulation resistance is 5000 megaohms, the effective test conductor capacitance to ground is 5 microfarads, the test voltage is 500 volts, and the fundamental. The most important reason for testing insulation is to insure public and personal safety. The motor used at that time is in a sound condition, and the insulation resistance reading through the measurement with an insulationresistance meter was 100 m. Pdf test of insulation resistance is prerequisite for leakage effect evaluation in many electrical measurements. An insulation resistance diagnostic system was recently developed and exercised during a series of cable fire tests sponsored by the commercial u.
The measurement of insulation resistance is a common routine test performed on all types of electrical wires and cables. How to measure insulation resistance with the fluke 1587. Specifications are subject to change and revision without notice. Equivalent circuit of cable insulation resistance test circuit where. This design is useful to find leakage due to insulation breakdown in transformer and motor windings.
Perform pv insulation resistance measurements safely. Power cables with extruded insulation and their accessories for rated voltages from 1 kv um 1,2 kv up to 30 kv um 36 kv part 1. R insulation resistance measurement of cable l cable length. Aug 04, 2014 determination of minimum insulation resistance the ieee std 432000 indicates that the minimum insulation resistance for ac and dc machine stator windings and rotor windings can be determined by. Troubleshooting with insulation resistance test instruments.
By examining the variations of the insulation value according to the test voltage application time, it is possible to assess the quality of the insulation. Insulation resistance testing is a nondestructive test procedure. How to measure resistance with a digital multimeter fluke. Measuring insulation resistance for threephase motor. The complete guide to electrical insulation testing. Measurement of winding resistance and insulation resistance of 3 phase 11 kv 433 v, 16kva oil cooled type transformer august 20 doi. The insulation resistance includes both volume and surface resistance and can be expressed as the parallel combination of the two. This absorption can activate conductive contaminants on the substrate surface or in the base material of the substrate. Insulation resistance ir is a measure of the insulating property of dielectric materials and is typically expressed in megohms. For discussion on insulation resistance measurement methods and procedures refer to milstd202 and astm american society for testing and materials standard d257. All digital multimeters have a resistance measure ment capability ohms. The new range of megger insulation resistance testers consists of three models.
Insulation resistance meter p n photovoltaic array e products used information valid as of september 2015. In principle, the value of the insulation resistance is very high but not infinite, so by. Application note leakage current and insulation resistance es. Diagnostic insulation testing at voltages above 1 kv is an area that is less familiar to many electrical maintenance personnel. Insulation resistance testing test equipment depot. The insulation resistance is subject to a certain degree of ageing however, moisture etc. This application sets the model 2450 to source 20 v and makes 10 resistance readings with a 100 ms interval time.
Insulation resistance measurement is based on ohms law. Cables for rated voltages of 1 kv um 1,2 kv and 3 kv um 3,6 kv reference number. Insulation resistance testing of low voltage cables in the. If a capacitor is tested at 200v and measures a dielectric leakage current of 10na the insulation resistance must be 20gw. The resistance of the leads is now subtracted from pending measurements until is pressed again. Insulation resistance testing introduction insulation resistance testers can be used to determine the integrity of windings or cables in motors, transformers, switchgear, and electrical installations. This behavior is primarily due to the fact that polymeric materials absorb moisture over time. Insulation resistance will always be 2000 megahms at or below 100c. Ideal for electricity board and industrial companies for predictive and. Testing insulation resistance of rotating machines, recommends the insulation test voltage to apply, based on winding rating, and minimum acceptable values for electric motor windings.
V of isolation resistance must be maintained from highvoltage systems to chassis ground. The main objective of insulation testing is to measure these leakage currents. The insulation resistance meter is a special instrument for measuring the maximum resistance value, insulation resistance, absorption ratio and polarization index. Material with high insulation resistance could possess a mechanical fault that might fail during a voltage test and conversely material with low insulation resistance might not breakdown during a voltage test. Facilities instructions, standards, and techniques volume 31. Preventive maintenance test with insulation resistance. Fluke insulation testers can now conduct the entire range of test voltages specified in ieee 432000 with a best in class, 3 year warranty and cat iv 600 v safety rating. Jp20140162a insulation resistance measurement circuit. The resulting current is called insulation current and consists of two main components. The voltage usually measures at least 500v, and causes a current to flow around the surface of the insulation. Measurement of insulation resistance ir part 2 fluke insulation resistance tester up to 10kv allows testing of high voltage systems such as control gears, engines, generators and cables. The ohmmic value of the insulation resistance is expressed in megohms m. Measure the insulation resistance at a test voltage of 500 v which varies depending on the battery voltage. Figure 2typical megger test instrument hookup to measure insulation resistance.
Ideal for electricity board and industrial companies for predictive and preventive maintenance. Instruction manual digital insulation resistance tester. Preventive maintenance test with insulation resistance test. This measurement is performed using an insulation tester, also called a megohmmeter. Only the current through the insulation is measured, since any surface current will be returned on the guard lead. This insulation resistance measurement system was able to identify and quantify the changes in insulation resistance occurring between the separate conductors and the conductors. Pdf measurement variations of insulation resistance. Technical information tempirsense the influence of. To perform an insulation step voltage test, apply the following procedure. For 3 terminal instruments mit4812, mit4852 only 17 result storage.
Oct 27, 2020 mesaurement of inslation resistance is quite important. A megohmmeter also called insulation resistance tester, teraohmmeter is then used to measure the ohmic value of an insulator under a direct voltage of great. Insulation resistance of dielectric materials under. The system or equipment is taken out of service and disconnected from all other circuits, switches, capacitors, brushes, lightning arrestors. Test lock test 617 9 5 di gi tal ins u lati on t es te r 100 0 v t est m. Understanding insulation resistance testing pdf 0712.
The megger insulation tester is a small, portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. You make insulation resistance measurements between traces on a printed circuit board and between conductors in cables and connectors. Measurement of insulation resistance ir part 1 index. Insulation resistance cannot be measured under high pressure. As an alternative, the insulation resistance temperature correction factor can be looked up from a table, for a given standard temperature 15. Measurement variations of insulation resistancepolarization. One method is to measure the insulation resistance of each panel with respect to ground. Application note leakage current and insulation resistance. Measure isolation resistance and insulation leakage currents to check the safety of occupants in the hev or ev system.
The reference design uses an onboard isolated 500v dc power supply and isolated signal conditioning circuit to measure the leakage current for determining the insulation resistance. This method allows conclusions to be drawn even if. If a circuit includes a capacitor, discharge the capacitor before taking any resistance reading. The megger insulation tester is essentially a highrange resistance meter. Set the megohmmeter to 500 v and connect to measure the resistance of each winding lead to ground. All digital multimeters have a resistance measurement capability ohms. What is the insulation resistance meter and how to test it.
Measurement variations of insulation resistancepolarization index during utilizing time in hv electrical machines a survey january 2015 measurement 59. The results obtained from ir test are not intended to be useful in finding localized defects in the insulation as in a true hipot test, but rather give information on the quality of the bulk material used as the. Its objective is to measure the ohmmic value of the insulation under a direct voltage of great stability, generally 50, 100, 250, 500, or vdc. This is a portable tool that is more or less an ohmmeter with a built in generator thats used to produce a high dc voltage. According to one aspect, a battery insulation resistance measurement method includes determining a voltage of a battery, determining a voltage of a first terminal of the battery with respect to a ground. Time may be saved if the generator winding is kept grounded until the test on the winding is made. It can be adjusted to all testing voltages that are specified in ieee 432000. Its scale unit is megger, which has a high voltage power supply. One test was run with the insulation resistance measurement system providing. For systems designed to work at more than a few volts, using the standard ohms function does not give us an accurate picture of the. Measure the insulation resistance of electric vehicles. Understanding insulation resistance testing aemc instruments.
Connect the insulation tester ir4053s e earth side to the ground terminal and the l line side to the photovoltaic cell strings p side. When insulation resistance measurements make it possible to verify if materials or equipment meet standard requirements, it is important to refer to these standards when choosing the measurement voltage. For good insulation, the resistance usually reads in the megohm range. Mar 03, 2021 loads such as motors and solenoids decrease in resistance over time due to insulation breakdown and moisture. During periodic tests the measurement of the insulation resistance is part of the measurements to be undertaken in accordance with din vde 0105100 vde 0105100. The standard duration of voltage application are 1 minute or 10 minutes.
The measurement of insulation resistance is a common routine test performed on all types of. A guide to diagnostic insulation testing above 1 kv. Understanding insulation resistance testing pdf 0206 rev. Basically, there are three different tests that can be done using a megohmmeter. The ieee also provides typical guidelines for for accurate low resistance measurements when using a dmm, insulation. Pdf measurement of winding resistance and insulation. Pdf a new method for insulation resistance measurement at low. Because of that, insulation resistance can also be referred as 1 minute insulation resistance or 10 minute insulation resistance depending upon the duration of the test. Connect the negative terminal of the insulation resistance tester to the ground point of the car body. Ranges in excess of v are not guaranteed for accuracy. Leakage current measurement reference design for determining. This method shares similarities with the astm d5470 standard, such as the measurement of the thermal resistance at different material thickness levels. Insulation testing is data intensive with several parameters, including electrical measurements and environmental conditions, collected.
Technical note the measuring current goes through the rtd element, but a negligible fraction is normally passing through the high insulation resistance riso 1. Fluke 1550c insulation resistance tester 5 kv, with. Megger guide to electrical insulation testing pdf instrumart. Be sure to measure the p side first and to verify that there is no degradation in the insulation.
As a production test, this test is often used as a customer acceptance test, with minimum insulation resistance per unit length often specified by the customer. I t total current supplied by the high voltage dc source i s stray leakage currents within test circuit not measured i l leakage current in test fixturing measured i. Assr601j insulation resistance measurement for photovoltaic. The test method is determined by the type of equipment being tested and the reason for testing. Insulation resistance test and oil test of distribution. Resistance measurements are then made between each winding and all other windings grounded. Insulation resistance testing guide chauvin arnoux. Insulation resistance testing, measuring, monitoring bender. For a vdc system, normal practice requires insulation resistance to be more than 1m. Insulation is a material property and is measured as insulation resistance.
Insulation resistance measurement is done using an ir tester. Tester performs at least 265 resistance measurements of 1. Measure the resistance value at the pside terminal, verify that there is no degradation in the insulation, and then measure the nside terminal. Calculation the insulation resistance can be calculated using the following formula.
Technical challenges in the measurement of insulation resistance. Standards jis c2 insulation resistance measurement, en626 emc, en6155712 dimensions 159w. May 27, 2020 with a sudden drop in resistance the 155x will cut the voltage and display the ramped voltage and resistance. Instead, we installed a known resistance r0 as shown in fig. We normally take the reading of the measurement at a certain time after application of test voltage. How insulation resistance is measured jm test systems. Insulation resistance testing, measuring, monitoring. Cable insulation resistance measurements made during cable. It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs. Figure 1shows the electrical schematic for an rtd and the insulation resistance connected to a temperature transmitter. Ieee std 432000 recommends a procedure for measuring insulation resistance of armature and field windings in rotating machines rated 1 hp, 750 w or greater.
Tida00440 leakage current measurement reference design for. The test measures the insulation resistance between the phases andor between phase and ground. Repeatability by definition repeatability of a sensor is the relationship of the original resistance at 0c and any different resistance at 0c after being subjected to the following test. Insulation resistance measurements should not be considered the equivalent of a voltage breakdown test. By having strong thermal insulation surrounding the diode, heat escapes only through an exposed cooling tab, which is used as the probe for the thermal interface material measurements.
Understanding insulation resistance testing pdf 0712 technical assistance 800 34391. With measurement storage and pc interface, the 1550c is the perfect tool for preventative or predictive maintenance programs designed to identify potential equipment failures. When measuring insulation resistance on a capacitor, it is recommanded to use the. The guard terminal is useful when measuring very high resistance values. Connect the positive terminal to each motor phase terminal.
Page 74 of 87 applications test sample resistivity measurements. Measuring the insulation resistance is often run in four techniques. By injecting a known dc voltage lower than the voltage for dielectric testing and then measuring the current flowing, it is very simple to determine the value of the resistance. Technical challenges in the measurement of insulation. Insulation resistance testing 19 measurement for 2 terminal instruments and mit2500 19 variable voltage insulation testing mit4202, mit4302, mit4852, mit2500 22. The insulation performance of electrical products is one of the important signs to evaluate its insulation, which is reflected by the insulation resistance. Insulation resistance measurements on pcbs are sensitive to environmental conditions. Testing solid insulation of electrical equipment, december 1991. Capacitor insulation measurement many actual electrical devices are equiped with input filters including capacitors to comply with emc standards.
1030 1018 465 1462 723 228 673 1498 793 1252 247 783 1071 859 817 333 371 1632 1496 1519 584 814 121 447 1256 1117 374