How big is the resistance of a 220V transformer to be considered normal?

This is a dual 12V transformer in the stereo, which seems to be very common in our home appliances. It can be tested in the absence of electricity, and generally do not plug in the test directly, because the short-circuit transformer is dangerous (the following is the low-power transformer used in the household mains 220V).

Distinguish between primary and secondary: Visual inspection generally has two lines for primary and three for secondary. The primary resistance is large and the secondary resistance is small.

<> use a universal meter ohm to measure the primary, and the bad ones are generally primary. Measuring the value of the primary open circuit, infinity or short circuit, the transformer can be judged to be broken. Normal should be in a few hundred ohms, this is only, this value is also abnormal, for 220V current is very large, if there is no insurance, then this transformer should be burned.

Below is a measurement of the normal value of a 9V transformer. 483 ohms is the normal range value for this transformer. If the value is less than two or three hundred, I will take a insurance to test.

The secondary is rarely bad, this is a normal 1 ohm, and it is about a few ohms. Both open and short circuits are abnormal.

I'm a beginner, so I'll share what I've learned. No academic qualifications. Only exchange experiences. Thank you.

The resistance value of the transformer depends on the capacity of your transformer, the number of turns is different, and the resistance value is different according to the length of the wire used in your drawing, copper or aluminum.

Insulation should be measured after new installation or overhaul and before transformers that have been out of service for a long period of time (three weeks).

A 2500V shake meter is used for high-voltage windings with a voltage level of 1000V or more, and a 1000V shake meter is used for low-voltage windings below 1000V.

Resistance value specification (20): 3-10kv for 300m-35kv for 400m-220kv for 800m kv for 3000m

The insulation resistance of the transformer is generally judged with reference to the original record, and the original record is low, although it is unqualified this time, it can also be put into operation close to the original record, and pay attention to the observation at the beginning of operation. When the resistance value is slightly lower than 30% of the original value of the standard and low voltage, the dielectric loss and absorption ratio of the transformer should be measured, and the preventive test should be carried out for further judgment if necessary.

The measurement of DC resistance is to check the welding quality of the winding and the inter-turn short circuit of the winding; Tap-changer position.

whether it is in good condition and whether its actual location is in accordance with the instructions; Whether the lead wire is broken or loose; Whether the winding of the parallel strands is wound or not. The measurement of DC resistance is an indispensable test item for transformers after overhaul, pre-test and changing the position of tap-changers, and it is also an important inspection item after failure. Therefore, the test must be performed with care to minimize measurement errors.

The regulations stipulate that the difference in resistance between phases of transformers above 160kva is generally not greater than the average value of three phases.

2%, the difference in resistance between lines is generally not greater than 1% of the average value of the three phases; For transformers of 160kVA and below, the difference in resistance between phases is generally not more than 4% of the average value of the three phases, and the difference in resistance between lines is generally not more than 2% of the average value of the three phases; The measured phase-to-phase difference should not be greater than 2% compared with the previous phase-to-phase difference measured at the corresponding part. When the resistance value measured by the DC resistance exceeds the standard:

The first consideration is whether there is a measurement error (such as whether the outer lead is connected, whether the test lead is too long or too thin, whether the contact is good, and whether the bridge is damaged.

insufficient voltage of the inner battery, etc.);

The DC resistance value is greatly affected by the Wenchang lift, so it must be converted to the same temperature (generally 20, r20=(t+20) (t+t), t copper=235) for comparison, and generally based on the upper oil temperature;

At present, the three-phase distribution transformer, the high-voltage winding adopts Y-shaped wiring, and when the resistance value exceeds the standard, the following formula RA=(RAB+RAC-RBC) 2,RB=(RAB+RBC-RAC) 2,RC(RBC+RAC-RAB) 2] can be used to find out the defective phase;

It is common for tap-changers to have poor contact, resulting in high resistance values, such as unclean switching, insufficient spring pressure, uneven force, and carbon deposits in the contacts during overvoltage.

etc., will cause the resistance to be high. At this time, the tap changer cover should be opened and turned back and forth several times, which can generally be eliminated.

The formula for the equivalent resistance of the transformer is that r is equal to pkxun 2 (1000xsn 2). By replacing several of the existing resistors with this equivalent resistor, there is no effect on the voltage and current flow of the entire circuit. If the secondary coil is connected to a pure resistive load rx, and the ratio of turns of the primary and secondary coils (ratio n1n2) is n to 1, then the resistance value of the load in the primary transformer is a square multiple of n of rx.

Transformer equivalent resistance formula information

In the steady state of the power system, there are mathematical models of transformers: un and sn are the fixed voltage and rated power of the exiang group, the equivalent impedance r is equal to pk*un 2 (1000*sn 2) x is equal to uk% * un 2 (100*sn), where pk transformer short-circuit loss percent uk short-circuit voltage percentage to ground admittance g is equal to p0 (1000*un 2) b is equal to percent i0 * sn1 set the ideal transformer original.

The number of turns of the secondary coil is N1 and N2, the voltage of the original secondary coil is U1 and U2, and the resistance of the secondary coil is R.

The formula for the equivalent resistance of the primary coil in the transformer is that r is equal to k square multiplied by r total, where k is the transformer ratio n1n2, and r is always the total resistance of the load in the secondary coil.

The insulation resistance value of the power transformer should not be less than 70% of the standard value at the time of delivery.

When detecting the insulation resistance of the power transformer, the black test wire of the megohmmeter is connected to the shell of the power transformer, and the red test wire is connected to the bushing wire of the power transformer, and the rocker of the megohmmeter is shaken clockwise at a speed of 120 rpm when measuring, and the resistance value indicated on the megohmmeter dial is the insulation resistance value of the power transformer.

There are three main groups of insulation resistance detection of power transformer, that is, between the primary winding and the secondary winding, between the primary winding and the shell, between the secondary winding and the shell, the insulation resistance value during the detection should be greater than 500m, if the insulation resistance value is small, it means that the insulation performance of the transformer is poor, and it has been damaged.

Precautions for insulation resistance measurement:

1. Before the insulation resistance test, it is necessary to carry out sufficient discharge, and it should be carried out in an uncharged circuit, and the condition of the test wire should be checked before the test, and the test should be checked to confirm whether the tested circuit is live, and whether the test wire connection is correct during the test.

2. Test the insulating surface of the items to be tested, choose the appropriate tester, put the tester well, adjust the level with a level, the value just tested will be low, and then read the value after it rises and stabilizes.

3. After the end of the test, it should be grounded and discharged, if the area structure of the test is large, it is necessary to pay attention to the length of the lead, and to do a good job of protection to avoid the lead being blown away by the wind and causing safety accidents. <>

Summary. Calculate the transformer current: 200 The success rate of conversion is about 288*400*.

The load is about 90 kw, and the current of 160kw on the first floor is 320A, which has exceeded the rated current of the transformer. Definitely can't be used. 200kva=200kw, the theory is not clear, kva is the apparent power, kw is the active power, the conversion is a multiple of kva is equal to kw, 200kva = 160kw is correct.

What is the high and low resistance value of a 200k a transformer.

Hello dear, I am glad to answer for you that K is the abbreviation of 1000 in mathematics - the file on the orange table is the resistance of the slag slag, and K represents the resistance unit of thousand ohms - here it is often abbreviated as K2K is 2,000 ohms resistance, and 200K is the crack 200 thousand ohm resistance. Hope it helps.

How many kilowatts of load can a 200k a transformer withstand.

Calculate the transformer current: 200 The success rate of conversion is about 288*400*. The load is about 90 kw, and the current of 160kw on the first floor is 320A, which has exceeded the rated current of the transformer.

Definitely can't be used. 200kva=200kw, the theory is not slag hand clear, kva is the apparent power, kw is the active power, the conversion is the times of kva is equal to kw, 200kva = 160kw is the right thing to refer to.

The flame resistance value of the winding of the power transformer can be calculated by the following formula, which is explained in detail in the power system analysis course.

<> these ** are the power system analysis, and the power transformer is calculated with component parameters.

Hello, I am glad to answer for you, the DC resistance of 20kva transformer is about 400m. This is because the high-voltage winding with a voltage level of 1000V or more uses a 2500V shake meter, and the low-voltage winding below 1000V uses a 1000V shake meter. Resistance value specification (20):

3-10kv for 300m -35kv for 400m -220kv for 800m kv for 3000m transformer insulation resistance, generally have to refer to the original record to judge, the original record is low, such as the liter this time although unqualified, and the original record of the oak resistance can also be put into operation, pay attention to the early stage of operation. When the resistance value is slightly lower than 30% of the original value of the standard and low voltage, the dielectric loss and absorption ratio of the transformer should be measured, and if necessary, the preventive test of Chang Combustion should be further judged.

Summary. In fact, the primary resistance of the transformer is determined according to the capacity of the transformer, under normal circumstances, the smaller the primary resistance of the transformer, the larger the capacity of the transformer, and vice versa. The primary resistance of a 220V to 36V transformer is generally because its capacity is smaller, so the primary resistance is smaller.

The primary resistance of the transformer is an important parameter of the transformer, which can reflect the capacity of the transformer, so when choosing the transformer, the capacity of the transformer should be determined according to your own needs, so as to determine the primary resistance of the transformer.

The primary resistance of 220V transformer to 36V transformer is generally, in fact, the primary resistance value of the transformer is determined according to the capacity of the transformer, under normal circumstances, the smaller the primary resistance value of the transformer, the larger the capacity of the transformer, and vice versa. The primary resistance of a 220V to 36V transformer is generally because its capacity is smaller, so the primary resistance is smaller. The primary resistance of the transformer is an important parameter of the transformer pure car, which can reflect the capacity of the transformer, so when choosing the transformer, the capacity of the transformer should be determined according to their own needs, so as to determine the primary resistance of the transformer.

Fellow, I really didn't understand, I can be more specific.

The primary resistance of 220V to 36V transformer is generally as follows. Reasons for the problem: 1. The primary resistance of the transformer is incorrect

Incorrect primary resistance of the transformer will cause the output voltage of the transformer to be unstable, which will affect the normal operation of the equipment. 2. Damage to the windings of the transformer: The damage to the windings of the transformer will cause the output voltage of the transformer to be unstable, which will affect the normal operation of the equipment.

Solution: 1. Check the primary resistance of the transformer to ensure that it is correct; 2. Check the windings of the transformer to ensure that they are in good condition; 3. If the primary resistance or winding of the transformer is damaged, the transformer should be replaced in time. Personal Tips:

1. When using the transformer, the primary resistance and winding of the transformer should be checked regularly to ensure that it is correct and intact; 2. The primary resistance of the transformer should be adjusted according to the actual situation to ensure that the output voltage of the transformer is stable; 3. When the winding of the transformer Yuyouliang is damaged, the transformer should be replaced in time to ensure the normal operation of the equipment.