What do you think is the difference between the insulation resistance test and the DC withstand volt

For the insulation resistance, it is measured with an insulation resistance tester (below 10000V) or an insulation shake meter (below 2500V), because the test voltage is relatively low, so many insulation defects are not easy to find; The withstand voltage test has a high test voltage, and it is easy to find the insulation defects of high-voltage equipment; Due to the low test voltage, the insulation test is not easy to damage the tested equipment; Due to the high test voltage, the withstand voltage test is easy to damage the tested equipment during pressure, especially in some cases, although the withstand voltage test has passed, but it has caused damage to the tested equipment, the tester should use the low voltage insulation test to test the insulation of the tested equipment after the withstand voltage test. Under normal circumstances, the insulation resistance is qualified, and the withstand voltage test will also pass. But, with a twist, there will definitely be special circumstances.

Because the high voltage generated by the withstand voltage test is generally more than twice the rated voltage of the electrical equipment, and the voltage value of the insulation resistance test is similar to the rated voltage. In addition, the withstand voltage test is alternating current, and the insulation resistance test is direct current. will have a certain impact on the test results.

Renshi also knows that the insulated megohmmeter emits direct current, and due to the relationship between the internal resistance of the instrument, the actual output current is very small, but for the withstand voltage test equipment, its internal is an AC transformer, and the output voltage and current are related to the capacity of the equipment. The reason why the insulation resistance value is very low does not break down the test object. <>

Hipot test is a non-destructive test that is used to check whether the insulation ability of a product is acceptable under the transient high voltage that often occurs. It applies high voltage to the equipment under test for a certain period of time to ensure that the insulation performance of the equipment is strong enough. Test voltage, most safety standards allow the use of AC or DC voltage in hipot testing.

If an AC test voltage is used, the insulator to be tested is subjected to maximum pressure when the voltage peak is reached, regardless of whether it is positive or negative. Therefore, if you decide to use DC voltage testing, you must ensure that the DC test voltage is a multiple of the AC test voltage so that the DC voltage can be equivalent to the peak AC voltage. For example:

For 1500V AC voltage, for DC voltage to produce the same amount of electrical stress, it must be 1500 i.e. 2121V DC voltage. <>

The insulation preventive test can be divided into two categories: one is the non-destructive test or insulation characteristic test, which is a variety of characteristic parameters measured at a lower voltage or with other methods that will not damage the insulation, mainly including measuring the insulation resistance, leakage current, dielectric loss tangent, etc., so as to judge whether there are defects in the insulation. Experiments have proved that this method is effective, but it cannot be relied on alone to reliably judge the electrical strength of insulation.

The other type is the destructive test or withstand voltage test, the voltage applied by the test is higher than the working voltage of the equipment, and the insulation test is very strict, especially to expose those dangerous concentrated defects, and can ensure that the insulation has a certain electrical strength, mainly including DC withstand voltage, AC withstand voltage, etc. The disadvantage of the withstand voltage test is that it will cause certain damage to the insulation. <>

First, the principle of the two is different:

1. Insulation resistance.

The principle of the test: the DC high voltage generated by the battery in the machine as the power supply through the DC DC conversion from the E pole to the L pole through the tested product, so as to generate a current from E to the L pole, and the insulation resistance value to be measured is directly displayed by the LCD after the I V conversion and the divider completes the operation.

2. Insulation withstand voltage test.

The principle is to apply a higher voltage than normal operation to the insulator of the device under test.

, for a specified period of time, the voltage applied to it will produce only a small leakage current.

The insulation is better. The test system consists of three modules: program-controlled power supply module, signal acquisition and conditioning module and computer control system. Select two indicators of the withstand voltage tester: the maximum output voltage value and the maximum alarm current value.

Second, the characteristics of the two are different:

1. The characteristics of insulation resistance test: large output power, strong load capacity, and strong anti-interference ability. The shell of this watch is composed of high-strength aluminum alloy, and there is an equipotential in the machine.

Guard ring and fourth-order active low-pass filter.

To the external power frequency and strong electromagnetic field.

It can play an effective shielding role.

For capacitive specimens, the output short-circuit current is greater than that, and it is easy for the test voltage to rise rapidly to the rated value of the output voltage. For low-resistance measurements, the voltage drop does not affect the test accuracy due to the proportional design.

2. Characteristics of insulation withstand voltage test: The withstand voltage test is a test of the withstand voltage capacity of various electrical devices, insulating materials and insulation structures. The process of applying a high voltage to an insulating material or insulating structure without damaging the properties of the insulating material is called a hipot test.

Generally speaking, the main purpose of the hipot test is to check the ability of the insulation to withstand the operating voltage or overvoltage, and then to check whether the insulation performance of the product equipment meets the safety standards.

Third, the use of the two is different:

1. The purpose of insulation resistance test: it is a commonly used and indispensable instrument for industrial enterprise departments such as electric power, post and telecommunications, communications, mechanical and electrical installation and maintenance, and the use of electricity as industrial power or energy. It is suitable for measuring the resistance of various insulating materials and transformers, motors, cables and electrical appliances.

2. The use of insulation withstand voltage test: It is mainly used for the withstand voltage test of polyethylene insulated power cables, and can also be used for large power transformers.

Insulation withstand voltage test. The hipot tester uses ultra-low frequency and high voltage to test the withstand voltage of power cables, which is a new method.

The insulation test is to detect the ability of the object to resist the current, and to measure the resistance of the object, which is tested with a megohmmeter, and the unit is mostly a megaohm. The withstand voltage test measures the ability of the object to resist voltage, and the breakdown voltage tester or high voltage generator is used to test the breakdown voltage of the object, and the unit is mostly kilovolts.

According to the voltage in the test process, the insulation test is divided into insulation characteristics test and insulation withstand voltage test. The former does not damage the insulator in the electrical equipment, so it is also called the non-destructive test, the non-destructive test is a commonly used method in the insulation test, which refers to the low voltage and non-corrosive state, through the test to determine whether the internal insulation of the electrical equipment is good, mainly including insulation resistance test, dielectric loss tangent test and other related tests.

The current form is different: the insulation characterizes the resistance, generally at the megaohm level, and the more intuitive the insulation length of the product, the larger the resistance, the better; The withstand voltage is the leakage current of the product after the high voltage is applied.

1. The principle of insulation resistance test: the DC high voltage generated by the battery in the machine as the power supply through DC DC conversion from the E pole to the L pole through the tested product, thereby generating a current from E to the L pole, and the insulation resistance value to be measured is directly displayed by the LCD after the calculation is completed by the divider through the I V transformation.

2. The principle of insulation withstand voltage test: add a voltage higher than the normal operation to the insulator of the equipment under test for a specified period of time, and the voltage added to it will only produce a small leakage current, so the insulation is better. Programmable power supply module, signal acquisition and conditioning module and computer control system.

The loss of talent can have a serious impact on a business. First of all, it directly affects the normal operation efficiency of the enterprise, which in turn causes a significant decline in productivity. Secondly, there will be a chain effect, which will have a negative impact on the morale of employees and cause the cost of human resources in the enterprise.

In order to prevent brain drain, the following three measures can be taken. First, it is necessary to broaden the career development channel of employees. Provide more development opportunities and room for improvement, and professional and technical personnel with excellent skills can get more rewards, improve the status of professional and technical personnel, so as to reduce the loss of professional and technical personnel.

The second is to improve the company's leave system. To meet the needs of employees for leave through rotational leave and cumulative leave, and under special circumstances such as tight project schedule, appropriate economic subsidies should be given to employees who have not taken leave. The third is to formulate a care action plan to achieve "one person, one file, one person, one characteristic", such as visiting the sick and elderly at the home of employees, celebrating birthdays for parents or wives of non-local employees, increasing parent-child project activities, re-entering employees, understanding employees, and solving employees' worries, so as to enhance the care for employees, increase employees' sense of belonging, and improve corporate loyalty.

In order to avoid the problem of serious enterprise brain drain through the effective implementation of human resource management, we must ensure that the development of human resource management adheres to the people-oriented concept. Managers can not only stand at the management level, but must go deep into the grassroots of employees, and closely link employee career planning with enterprise development, so that employees can more actively participate in the job work and have a good sense of belonging to the enterprise. The pace of employee development must be consistent with the pace of enterprise development, take the enterprise development goal as the goal of their career, and regard the enterprise as their "family", take root here and grow here.

Road and bridge construction enterprises have certain particularities, so its human resources assessment standards are bound to be different from service enterprises, but from the actual situation, a large part of road and bridge construction enterprises have not been able to establish a standardized, quantitative evaluation and incentive system to date, in the process of actual evaluation, the content of the evaluation system is difficult to implement, has brought a certain negative impact on human resource management. To solve this problem, companies can do two things. First, the high-quality assessment and evaluation system can make employees have a certain sense of responsibility and self-identity, so in the future work must be formulated as soon as possible to develop clear assessment objectives, combined with the needs of different professions and different positions, the existing assessment content and evaluation standards are adjusted, and the actual situation is taken as the starting point, do a good job in qualitative and quantitative evaluation, ensure the effectiveness of the evaluation through a sound and perfect system, and make appropriate adjustments to the employees' job treatment according to the results of the assessment and evaluation.

Second, it is necessary to combine the requirements of different positions for personnel ability, establish different employee incentive mechanisms, and cannot manage all positions in the same mode, otherwise it is difficult to achieve the expected results.

Generally, the insulation resistance test needs to be carried out before the withstand voltage, because the withstand voltage test is a loss test, if the insulation test of the winding is in a slight failure state (there are real damage and damp conditions), if the withstand voltage test is carried out directly, because the voltage is very high, the degree of damage will be expanded, and the wire will be burned out in serious cases, thereby increasing the difficulty of repair; It may also penetrate the damp. Insulation measurements, on the other hand, detect insulation failures (including insulation drops due to moisture) and generally do not extend insulation damage during the measurement process. Before the withstand voltage test, the insulation resistance test is carried out, and the insulation resistance is found to be unqualified, so it is repaired, which may be much less than the breakdown and repair workload after the withstand voltage test, and the insulation resistance caused by moisture is low, as long as it can be improved to a normal state by drying and other means.

It is not necessary to test the insulation resistance after the withstand voltage test.

Strictly speaking, insulation tests should be carried out before and after the withstand voltage test of electrical equipment. The purpose of the insulation resistance test before the withstand voltage is to judge whether the electrical equipment has the withstand voltage conditions, when the insulation resistance is unqualified, the cause should be found out and repaired, so as to prevent the expansion of equipment defects due to blind withstand voltage, or even difficult to repair. When the equipment is well insulated, the insulation resistance value after the withstand voltage should be equal to or higher than the insulation resistance value before the withstand voltage, because through the action of high voltage, the bubbles in the insulation or the tip burrs on the microscopic level will disappear or decrease.

Because the insulation resistance value after withstand voltage is the final resistance value of the equipment to make a factory record, for reference in the future use process.

The purpose is differentThe purpose of the DC withstand voltage test is to test the highest voltage peak that the operation of electrical equipment can withstand;

The purpose of the AC withstand voltage test is to test the dielectric strength of power equipment;

For the cable, it is just a power transmission device, the resistance is extremely low, and it is pointless to test how much voltage it can withstand without heating up; The cable needs to be insulated from the surrounding environment to avoid loss of power resources or danger, so the AC withstand voltage test should be selected.

First, the nature is different.

1. AC withstand voltage: the most effective and direct method to identify the dielectric strength of power equipment.

2. DC withstand voltage: the maximum voltage peak value of the detection equipment under the high voltage test.

Second, the destructiveness is different.

1. DC withstand voltage: Since the insulation under DC voltage basically does not produce dielectric loss, the damage to the insulation caused by DC withstand voltage is small. In addition, since only a small leakage current is required for the DC withstand voltage, the required test equipment has a small capacity and is easy to carry.

2. AC withstand voltage: AC withstand voltage is more damaging to insulation than DC withstand voltage, because the test current is capacitive current, large-capacity test equipment is required.