Ipctm650 embedded devices test methods subcommittee test. After having verified that the test procedure was correct and that the supply was correctly installed, an investigation of the test voltage found that the voltage applied was in excess of 1,500vac, but not at the 3kv or 4kv level. Jul 31, 2017 the purpose of the dielectric withstand hipot test is to determine whether the insulation from the primary circuit to grounded or accessible parts has sufficient electric strength to withstand the normal overvoltages which could occur in service. The ac test will stress the switchgear insulation similarly to the stresses found during operating conditions. The pts series of dc hipot test sets provide continuously adjustable output voltages for the test and measurement of leakage current in high voltage insulation. To figure out what could cause such failures, i decided to current limit the hipot tester with a highvoltage series resistor. This is primarily due to the availability of other test methods and the high levels of power consumption. As long as the buttons are held down the hipot test will happen. My colleague uses a programmable acdc hipot tester to 1 determine that a unit under test is truly connected to the hipot tester and 2 conduct a dc hipot test. Some passed initially, then failed later in functional testing. Hipot, insulation, leakage current and pegbtesters. This function is to change the time required for the outputted test voltage from the specified value falling to zero. The typical highpotential hipot test is an example of a type 1 field test.
Between contacts and shielded, the puncture voltage must not less than 1. Trsrentelcos hipot test equipment cover a wide voltage range from 5kv to kv. We find that it helps many people understand specifically how high voltage tests identify. Caution in case of use for combining more than 2sets of high voltage. It was not clear why the higher voltage test was being applied but the test lab was adamant that it was correct. Figure 4typical record of insulation resistance of a mill motor. Dc hipot tester hipot test procedure electrom instruments. Ac hipot tests 15 dc hipot tests 15 arcing 16 line regulation 17 load regulation 17 ramping 18 minmax current detection 18 ground continuity test 18 polarization test 19 ground bond test 19 insulation resistance test 20 measurement procedure 21 dielectric absorption 21 charging current 21 leakage current 21 leakage current test 22. The hipot test the dielectric voltagewithstand test is commonly known as the hipot test. This type of system works for fast hipot tests but can be.
Hipot testing stresses the insulation and capacitors of. Combine 500 test procedures totally or 100 sets of memory function. Dc hipot test at test start, there will be inrush current. Timely conducted testing procedures can help notice the loss of cable insulation integrity, spot signs of its deterioration caused by aging, and therefore prevent cable failure. Please refer to the above procedure to select correctly the remote trig. The test is a means to qualify a devices ability to operate safely during. It should be made only after the dc insulation resistance measurement test has been passed satisfactorily and all cleanup has been finished. Inspect whether leakage current of acdc power flows to ground terminal is over standard. Often this english term is even more common than the expression high voltage tester literally translated from german. We have all used ac hipots for decades to test various types of equipment.
Reverse side of card at right is used to record the test data. If a display fails the onesecond test method, redo the test using the sixtysecond etl test outlined below, as required by article 36 of ul standard 1433. Safety guidelines for hipot testing and setting up a safe. The case is very rugged and provides room for cable and accessories. One safe and effective testing method offered by industrial tests, inc. The dc voltage potential in the windings is rapidly raised to a predetermined level, or raised in steps up to this level, depending on what test method is used. Understanding hipot certification testing electronic design. Sefelec reference pent0438 operating manual xs series. Apply an ac hipot test to confirm insulation does not leak. Using the right diagnostic tester keeps equipment operational so that users are able to ascertain whether insulation is functioning properly. It is the data behind the hipot test that can help manufacturers ensure the product is safe and consistent. The main advantage of the dc test is dc voltage does not produce harmful discharge as readily occur in ac.
Withstand or hipot cable testing withstand or hipot testing is used to evaluate the condition of cable insulation during installation, acceptance, or maintenance testing. If this is a mystery, a simple water metaphor may help you understand hipot testing a little better. Dc high voltage testing is not a substitute for ac in most cases and should be avoided. Designed to verify that the insulation of a product is adequate enough to withstand high voltage. A dielectric withstand test or high potential or hipot test is an electrical test performed on a component or product to determine the effectiveness of its insulation. The hipot test is usually a 100% production line test and can be performed using either an ac or a dc voltage. The dielectric test set can be used to determine insulation resistance by the same test methods. If either switch is released, the hipot test aborts.
When ac hipot tests are used for routine maintenance, the power transformer can be examined at rated voltage for 3 min instead of testing at 65% of factory test voltage. The shock accidents are usually occurred on the following conditions. Megger guide to electrical insulation testing pdf instrumart. Aug 20, 2017 why we do hipot test,types of hipot test and basic of. The paper will further extrapolate to educate oems the full guidelines regarding what hipot testing is designed for and the difference for high potential individual net testing. Dont touch any charge component of connecting output terminal. The test voltages to be used vary depending upon whether the device or circuit is low or high voltage, a primary or control circuit and whether tested at the factory or in the field. During cable pulling, cable is sometimes subjected to physical stress due to excessive force exerted on it that could eventually leads to damaging the outer layer parts that serve as primary protection of the cable. How dc hipot works dc voltage is applied to open disconnected windings by the hipot tester or motor analyzer.
It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs. Continuity test checks surety of current flows easily from. It is then maintained at this value for one to ten minutes 3. Then a single wire or network of connected points called a net is disconnected from 0v and connected to the ac source see figure 2. Understand that each step in the work plan must be executed as planned. This is an important part of the test procedure, since this impedance. Hipot test is a contraction for high potential hv testing. The test may be between mutually insulated sections of a part or energized parts and electrical ground. Very low frequency vlf testing hipot testing california. Highpotential testers hipot locate tolerance errors and nicked insulation, and perform successful production line hipot testing in manufacturing with our selection of hipot test equipment.
Hipot setup and testing for hipotronics hd103 and hd106 acdc voltage testers overview to ensure your own personal safety and the safety of your coworkers, and to be sure that our displays are suitably tested to ensure customer safety, it is essential that you understand the proper setup and use of our hipot testers. Hipot tester 190711907219073 users manual for the outputted test voltage from zero rising to the specified value. May 01, 2014 hipot testing 101 this archived webinar covers. Now they can be used for field testing cable and rotating machinery. Safety, operation, and procedure instructions for the pts. He programs the first step of the hipot tester sequence for 250 v, 60 hz. Merging technology on units requires more in depth test verification than on old. Mar 08, 2016 apply an ac hipot test to confirm insulation does not leak. These features are used with a dc hipot or ir test. This test of the dielectric strength is mandatory as it is part of the requirements of all national standards e. The dielectric voltage withstand test page 2 the dielectric voltage withstand test is an integral part of the product safety evaluation of electrical and electronic devices, and provides manufacturers with important information regarding the quality and appropriateness of the chosen insulation system. The current standards provided for the use of dc hipot testing for acceptance testing of cables are recognized by the current industry standards. The hipot 150 is a portable high voltage test set that is designed to locate faulty insulation on electrosurgical instruments and accessories.
Because the products highvoltage power supply uses the pwm switching method, if the test voltage is 500 v. Electrical safety testing reference guide touch area. Meanwhile, your heart palpitation unregulated and blood pressure falling down causes tragedy cant be redeemed. Later, hipot highpotential testing started to fail on random units at a 10 percent rate, which was much higher than i expected, since the supplier tested before shipping. Hipot testing shall not be conducted on test specimens that have previously been exposed to high voltage levels or other similar testing. Voltages, dwell, ramp and current cutoffs will be explored.
In this scenerio it appears that the hipot test could in very rare cases burn out the unit and by not running the functional test first could cause a dead unit to get to our customers. To allow a hipot test an operator must use each hand to hold down a button. However, it provides limited knowledge of the cable condition other than whether the cable system withstood the voltage for the duration of the test or not. The megger insulation tester is a small, portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. If the hipot does not have a complete circuit, it cannot discharge the dut at the end of the test. Hipot test standards dc hipot test analysis electrom. Testing of high voltage cables manual horizon power 1st edition february 20 prepared by field practices. This guide provides a general overview of the regulatory framework and approval process and explores the specific manufacturing responsibilities and test procedures associated with electrical safety testing. Sep 25, 2015 a minor disadvantage of the dc hipot tester is that because dc test voltages are more difficult to generate, the cost of a dc tester may be slightly higher than that of an ac tester. Watch the ampere meter while the voltage is increasing if the value hits the current limit before the test voltage is reached, you may have to increase the voltage ramp time to offset for the capacitive load. Curve b shows same values corrected to 20c see page 22, giving a definite downward trend toward an unsafe condition. In this case the operator only needs to load the board to the machine and initiate the test. A dc hipot test should be used only when a vlf test set is not available. Propulsion laboratory and as given in jpl internal documents nos.
A hipot test starts with all of the points in a cable held at 0v. We now have the means to hipot high capacitance coils or long hv cables in the field with relatively portable and affordable ac test equipment. Due to the nature of a dc withstand test, setting high and low leakage limits can prove difficult. Very low frequency vlf withstand testing the basics. Very often the word hipot tester is mentioned in connection with the high voltage test. Its easy, quick, conclusive, and supported by ieee standards and used. The dielectric voltagewithstand test is commonly known as. The product supplied power for avayas voip phones in a distribution box with 10 watts for each device inline on rj45 ports which ran at t1 or 1. This combination of size and power makes very low frequency cable testing perfect for testing longer sections of cable and apparatus. Dec 01, 2011 hipot test is short name of high potential high voltage teat and it also known as dielectric withstand test. Cable types, design, and associated insulation faults. Below are hipot test voltages for both dc hipot and ac hipot tests. Acceptable procedures for conducting hipot testing, although varying slightly in technique, have been standardized as either a withstand test or a timeleaking current test. Hipot test is short name of high potential high voltage teat and it also known as dielectric withstand test.
Hipot 150 electrosurgery instrument insulation tester. The megger insulation tester is essentially a highrange resistance meter ohmmeter with a builtin directcurrent generator. Ieee std 400 provides additional information on dc testing and evaluation of the insulation of shielded power cable systems c. Therefore, if a test of an installed motor in a plant fails above peak operating voltage, it does not mean that the dut itself has failed and cannot continue to operate, or that it needs to be.
Nov 09, 2015 ac hipot test this test should be conducted separately for circuit breakers and switchgear buses stationary gear. Better and easier setup for production line hipot testing. Single testers are often used at manual work places, in laboratories, for the inspection of incoming goods. Hipot test is the most common type of electrical safety. For proof tests of new unused motors, the test voltages are as follows per ieee 95, iec and ansieasa ar100. The dielectric withstand hipot test in compliance magazine. Electrical safety testing reference guide power sources. In some ways a hipot test is the opposite of a continuity test. Ac hipot testing ac high potential tests are conducted at voltages above the normal system voltage for a short time. Dc hipot testing electrical test equipment power station. Its important to remember that this method of arc detection is not an exact science. Vlf testing uses very low frequencies as part of an ac cable maintenance routine. Image you are bathing in bath tube, suddenly drier in operating dropping into bath tube, the current flows from drier through your body to ground under this situation. This test is known as a hipot, proof, withstand, stress, gonogo, pressure, or over voltage test.
Thus, a dc hipot test voltage is often derived from a typical ac hipot test voltage which is proven to work well. Vlf hipot test is the preferred method of highpotential testing and should be used whenever a vlf test set is available. The test measures the insulation resistance between the phases andor between phase and ground. A hipot test checks that no current flows between points where there should be no current. Hi pot dielectric breakdown automated verification howto. Dont touch test cable of connecting test termination. Hipot testers determine the suitability of the dielectric or insulation barrier between hazardous and nonhazardous parts. High voltage test also called hipot or hv test worldwide has by far the highest priority among all of the electrical safety tests. Figure 3typical scale on the megger insulation tester. Press the green test button and observe the following precautions. Testing of high voltage cables manual horizon power. Vlf testing is used for any application requiring ac testing of high. Hipot test is the most common type of electrical safety test.
Hipot test is short name of high potential high voltage test and it is also known as dielectric withstand test. High potential testers dielectric test equipment trsrentelco. The voltage is slowly increased to a predetermined overpotential value. As the instrument end the test or turn off output, please dont touch test unit immediately. Hipot test current, leakage current and insulation resistance. A dc hipot test is done at a voltage higher than the peak operating voltage of the device under test dut, where peak voltage rms voltage x 1. The choice of the right method and the most appropriate instrument before moving on to the main hipot testing techniques, it is. Hipot test makes surety of no current will flow from one point to another point. A ground continuity test assures the ground wire of a product is intact. With the proper programming interface to the hipot analyzer this test can reduce much time. A low voltage is applied from the chassis of the product to the ground pin to determine if the appropriate amount of current flows. The pairs are programmed in an adjacency method for the flying probe. The powersupply vendor verified that the test procedures and powersupply installation were correct.
Withsta nd test apply high voltage on power and ground terminal circuit of product to measure its collapse status. When combined with a ground continuity test to ensure integrity. The object either passes the test by holding the test voltage or fails by flashing over or through its insulation. Its just an ac hipot but with a lower frequency output. Insulation resistance testing is a nondestructive test procedure. Electrical safety tester verification associated research. High potential tester hipot t 991 megger is the originator of the insulation tester with over 100 years of experience and leadership in providing high performance insulation testers for electrical equipment diagnostic applications. Hipot testing dielectric strength testing appears in nearly every product safety standard and is a fundamental test used to check a fully assembled product as it exits the production line. This discussion will also focus on testing of stator windings and not on testing individual bars or coils. Dc high potential testing dc hipot testing purpose dc hipot testing is used for proof testing shielded cables 5kv to 46kv in the field. The hipot tester is the short form of high potential tester and is mainly used in the international language. The conventional dc hipot test is considered a passfail test similar to the ac test. Hipot testing is an abbreviation for high potential testing a category of electrical tests used to verify the effectiveness of electrical insulation in transformers, motors, printed circuit boards, electrical sub. Changing the time for voltage falling this instrument contains fall function.
Hipot testing has long been a standard procedure for assuring the electrical safety compliance of electronic equipment. Ac hv test value should not surpass 75% of the factory test value. Because the products high voltage power supply uses the pwm switching method, if the test voltage is 500 v. Performed by stressing the insulation of the product far. That is why the mg series units allow to combine the imax and the. Pdf why testing is important, what tests are most common, and how preventive maintenance can make all.
The test can be done at various times such as acceptance of new cable installation, maintenance testing to track insulation degradation and as a pre and post test for splicing existing cables to new ones. Dry testing transformer series is produced, it is completely changed by the backward state of old test transformer stupid, big and heavy, it can produce our matching mounted on a highvoltage silicon stack to provide dc highvoltage test power supply, with a control box,automatic protection microammeters, gap and other ancillary equipment. A very low frequency vlf withstand test is an ac withstand test usually carried out at a frequency between 0. The current meter on the pts series also has a megohmmeter scale to allow for easy resistance measurements while the hipot is in operation. Vlf testers are smaller and more practical than ac testers but output the same amount of power as a 50 hz mains device. The method of running a hipot test involves applying the high voltage. Ammeter clear test a lowvoltage test using a 60 hz 125v ac power. Understanding the hipot test how to perform the hipot test hipot test requirements understanding failures. The hipot 150 supplies a high voltage at a very low current. The description of these tests will not apply to watercooled stator windings since the test procedure and analysis differ for watercooled units.
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