Reviews I bought the phone for my grandson in the MTS salon.
When making a purchase, I was offered insurance, when consulting on reimbursement of insured events, the seller referred to the following points: theft - 3.3.4; the impact of foreign objects - 3.3.5; external mechanical impact - 3.3.8. This is exactly what I would like to insure against.
In April 2017. the grandson went to the skating rink (to go for a drive, and not to kill the phone with malicious intent), the phone was in his pocket, but where else could he lie? During skiing, an emergency happened, the child fell and hit the ice just on the side where the phone was. During the examination, the screen is badly broken and the phone does not respond to the requested functions (does not work).
Examination of the phone (for example SAMSUNG S ΙΙΙ mini GT-I8190)
Examination of the phone (for example SAMSUNG S ΙΙΙ mini GT-I8190)
- Manufacturing defects
- Is the SAMSUNG S ΙΙΙ mini GT-I8190 mobile phone defective?
- Violations of the rules of operation
- What defects were identified during the study?
- Are the identified defects a consequence of:
- The consequence of an unqualified repair
RESEARCH PROCEDURE: defects of the investigated equipment were carried out by visual inspection.
Refusal to pay insurance indemnity Extension of the guarantee, the provision of services under a certificate is possible only if these documents are available.
The certificate begins to be valid from the 16th day following the day of purchase. YurClub conference 3.02.2018, having learned by phone about the refusal to recognize the case as insurance, I turned to the official Sony service center, where 10 days later they returned the phone to me with a letter in which the service center refuses to carry out warranty repair of the phone, since it was impossible to do this when broken screen.
Smartphone insurance
Divorce from sellers or a useful service?
Almost in any cell phone shop, the buyer will be intrusively offered to insure the smartphone that he is going to buy.
The sales assistant will beautifully talk about the benefits of this service. Drown, smash, lose your phone - and you will be refunded for it.
As you can imagine, everything is so simple and beautiful only in the stories of sellers.
Is the case covered by insurance? (phone insurance)
Is the case covered by insurance?
(phone insurance) Good afternoon, in any case, the insurance company first conducts an examination to establish the insured event.
If you do not agree with the conclusion of the examination, then you can conduct an independent examination at your own expense.
Phone repair under warranty can only be counted on during the warranty period. But, not all phone breakdowns are recognized as warranty and often the service center specialists refuse to accept the phone for warranty repair. What is the reason for the refusal to accept the product for warranty repair? Let's try to figure it out.
Imagine the situation. You bought a phone from a store. After a while, it stopped working. Of course, you take it to a certified service center for warranty repair. You take him for diagnostics.
Some time passes and you are again invited to the service center. You expect that the phone will be in good working order, but instead of a work phone, you are handed it the way you handed it in for repair.
At the same time, you will be given a copy of the expert's technical opinion that the breakdown is not a warranty case.
What can you advise in this case?
Before signing the phone inspection report and technical report, carefully study their content.
Unfortunately, not all service centers do decent business. And often, allegedly by mistake, you may be denied warranty repairs. And, if you sign such an act and conclusion, you will not be able to return anything.
Carefully study the reason why your phone was removed from the warranty.
As a rule, this happens when third-party services interfere with the product. Despite the high qualifications, if the service center is not authorized by the manufacturer to repair equipment, then after repair by third-party masters, such equipment is removed from the warranty.
As a rule, if a phone with a valid warranty gets into a decent service, then the masters warn the client that after the repair the phone will be removed from the warranty. This happens even with minor repairs in the form of replacing the charging port.
Do not forget that any repair of the warranty phone, without harm to the warranty agreement, can be carried out only in special authorized service centers.
Even the replacement of a broken port must be done by the officials. Then the warranty is not lost and in case of defects, they can be eliminated under warranty.
Protect your phone from moisture!
It is highly recommended not to take a bath while using your phone. Also, when taking a shower, listening to music on your phone is also not worth it. Despite the fact that the phone itself does not get into the water, water vapor gets into it, which settles on the microcircuits and spoil them.
If, upon handing over the phone for warranty repair, moisture is found in it, then the device will be removed from the warranty unambiguously.
The warranty is also affected by improper use of the phone.
Mechanical damage to the phone will also lead to a denial of warranty repair. If, upon examination, traces of impact or squeezing are found on the phone case, then you can not count on warranty repairs.
Also, if the phone fell on a soft surface, but the impact was strong enough to break the display, then such a case is also recognized as not guaranteed. Since it is impossible to break the display under natural conditions of use.
Therefore, try to carry your phone with care, do not drop it or sit on it. It is better not to carry your phone in the back pocket of your jeans, as you can forget about it and sit down, crushing the display.
Having carefully read the technical report, carefully examine your phone and compare its condition with the data in the act according to which you handed it over for repair. If everything is in order, then the documents can be signed.
The technical conclusion must be signed by the warranty master and the head of the service center.
If you do not agree with the technical opinion, then according to the law you can order an independent examination. If you decide to go to the end, then do not forget that with an independent examination, the result may be the same.
The fact is that there is no need for the service center masters to refuse you a warranty repair, if there is no reason for this. The manufacturer pays for warranty repairs to the service center. And the manufacturer will not pay anything for refusing to repair.
But the service center masters will also not receive anything if they repair your phone in violation of the manufacturer's warranty policy. The manufacturer immediately debits such a work order.
In this case, it is better to make repairs in a regular workshop. It is better to choose craftsmen who have been working for a long time and workshops that are famous in the city. It is better not to contact small private owners. As a rule, in unauthorized workshops, the cost of any repair is up to three times cheaper.
What should I do if my phone is refused warranty repair due to the presence of damage caused by negligence?
After the service center refused to repair under warranty, you need to proceed as follows:
- Study the text of the technical opinion itself carefully.
It should describe in detail what happened to the phone, what problems were found.
It must be described what kind of damage gave rise to the refusal of warranty repair and the reasons for their occurrence;
- Get an act of completed work in your hands on your phone. It should indicate what exactly was done and what result it led. So you can check the diagnostic method and its objectivity;
- Since the act must contain an indication and the reason for the occurrence of damage, it must be indicated that such damage was not hidden and could not be unknown to the buyer at the time of purchase;
- If you do not agree with the results of the examination of the service center, then you have the right to conduct an independent examination of the phone. Its results can help in the judicial resolution of the conflict;
- Often sellers refuse to carry out an independent examination and limit themselves to the conclusions of the experts of service centers. Remember that you have the right to request an independent review at the seller's expense. And if the problem with the phone is confirmed, then you will not have to reimburse the costs of the examination;
- If the result of the examination confirms the seller's correctness, then you will have to reimburse the seller for all the costs of transporting the phone to the place of the independent examination and carrying out the examination itself;
- If the problem with the phone seller cannot be resolved, then the last chance to restore justice will be going to court. But remember, the court doesn't believe the words. The court needs confirmation. To win a consumer protection case, you have to prepare evidence for each circumstance that you plan to set out in the text of your statement of claim.
Be sure to follow these guidelines and your chances of success in court will increase. According to the general rules of civil law, the party that lost in court is obliged to reimburse the winning party for all costs that it incurred in connection with the litigation. As practice shows, it is consumers who most often manage to convince the court that they are right.
Warranty and non-warranty phone malfunctions
According to the law, the goods that are covered by the warranty and in which defects were found are repaired at the expense of the organization that sold it.
Warranty cases include many situations in which a product breakdown occurs. But the warranty agreement with the end user, that is, with you, will play an important role.
Therefore, when buying equipment, pay special attention to the warranty documents.
Warranty documents must accompany each new product that is sold to the user. In a warranty agreement (its role is often played by a warranty card), as a rule, certain circumstances are indicated that will definitely be recognized as not guaranteed.
Usually, the warranty repair of a mobile phone is denied in cases where:
- The use of the phone was not performed according to the manufacturer's guidelines. If the phone was not used for its intended purpose, water got on it, moisture got into the case, the phone fell, overheated, burned out due to a voltage drop;
- Mechanical damage (the phone fell or sat on it);
- Incorrect phone storage. Storage at low temperature, high humidity, high temperature, near strong electromagnetic radiation;
- Lack of warranty (if the buyer bought the phone on sale and was notified of the possibility of hidden flaws);
- Using an incompatible charger to charge the phone battery;
- Interfering with the phone software (flashing);
- Broken battery, flash memory and other phone accessories.
If you are absolutely sure that the phone stopped working through no fault of yours, feel free to contact the store where you bought it. All expenses for the examination will be covered by the seller.
You have the right to be present at each examination. Also, if the experts establish that the breakdown of the phone was your fault, then you will have to pay all the expenses for the examination. But the seller will have to achieve this through the courts.
Mechanical influences are static, vibration and shock loads, linear accelerations and acoustic noise. They cause fracture due to stretching, compression, bending, torsion, shearing, indentation, and material fatigue.
Products designed to function under mechanical stress must be durable and resistant to impact. Products that are not intended to function under mechanical stress must only be durable when exposed to them.
Figure: 2.1.
Resistance to mechanical factors is the ability of products to perform their functions and maintain their parameters within the established norms during exposure to mechanical factors.
In practice, they usually deal with complex loading, in which a complex of mechanical loads - static and dynamic - acts on the product. The nature, magnitude, direction and distribution of efforts, stresses and other factors can change over time. Without proper consideration of the entire complex of loads and their changes over time, it is impossible to correctly assess the strength properties of products. During operation, during transportation, movement and storage, products and materials are exposed to dynamic loads.
The most common factors of dynamic mechanical stress are vibration loads. The inertial forces arising from vibrations can cause stresses that exceed the strength and endurance limits of the structure. The intensity of vibration is characterized by the frequency and amplitude of the vibration, as well as the magnitude of the maximum acceleration. Vibrations are mechanical vibrations in the frequency range 0.1 ... 2000 Hz and more, displacement amplitudes 0.001 μm ... 100 μm and more, acceleration amplitudes up to 1,000 m / s 2 and more. Most of the vibrations encountered in practice are in the form of a distorted sinusoid.
The parameters of linear vibration include displacement, speed, acceleration, sharpness (the third derivative of displacement over time), force, power. The parameters of angular vibration include the angle of rotation, angular velocity, angular acceleration, angular sharpness, and moment of forces. The parameters of both types of vibration also include phase, frequency and harmonic distortion. The nature of vibrations, both in frequency and in amplitude, can vary significantly from design to design, depending on the operating conditions of the products and other influencing factors. The greatest danger is the multiplication of vibrations that occurs at the resonant frequencies of elastic structures.
Vibration loads created by various power plants, equipment, as well as unbalanced rotating and moving parts of machines, cause destruction of the structure of a fatigue nature, disable fasteners, contribute to the appearance of a "microphone" effect and disturb the settings of controlled elements, cause short circuits and breaks in electrical circuits elements of electronic and electrical devices, lead to a violation of the sealing of the blocks.
Depending on the magnitude and type of vibration loads, the degree of rigidity of the product is established and tests are carried out for vibration strength, vibration resistance and detection of structural resonances. Vibration testing uses sinusoidal, random broadband or vibration previously measured on the prototype.
Shock loads also often found in the operation of modern structures, machines and devices. Mechanical shocks can be single, multiple and complex. Single and multiple impact processes can affect an object in the horizontal, vertical and inclined planes. Complex shock loads affect the object in two or three mutually perpendicular planes simultaneously. Shock loads of products can be both non-periodic and periodic and can have both variable and the same degree of rigidity. The occurrence of shock loads is associated with a sharp change in acceleration, speed or direction of movement of products. A complex single shock process is most often encountered in real conditions, which is a combination of a simple shock pulse with superimposed oscillations. The main parameters of the impact process are acceleration, displacement, speed, deformation of the considered point of the body under impact. The shape of the shock pulse is important. Products that have received a blow are shaken, and rapidly damping natural vibrations are excited in them. The magnitude of the overload on impact, the nature and speed of stress propagation over the product are determined by the force and duration of the impact and the nature of the acceleration change. Impact, acting on the material and product, can lead to mechanical destruction.
Loads from linear accelerationsarising in the nodes of rotating mechanisms. The effect of centrifugal acceleration is determined in each of three mutually perpendicular directions with respect to the product. Linear accelerations vary up to 10 4 m / s 2 and more.
Acoustic noise - in most cases, an interfering factor that can also affect the ability of products to perform their functions. The most common noise frequencies are 125 ... 10000 Hz, the maximum sound pressure level is 200 dB or more. To take into account the effect on the products of changes in the noise frequency, appropriate tests with a tone of a varying frequency of 125 ... Acoustic noise has a significant effect on relatively large items. Therefore, semiconductor devices, microelectronic products are not very susceptible to the destructive effects of sound pressure. The effect of acoustic noise on products depends on the magnitude of the force on the product, the determined sound pressure level and the area of \u200b\u200bthe product. The mechanism of the destructive effect of sound pressure is similar to the destructive effect of vibration. In this case, as a result of the action of the energy of the oscillation of the sound frequency in radio-electronic devices, a "microphone" effect occurs and resonance phenomena appear.
I decided to write how to competently deal with the insurance company.
By phones. Tablets and technology. PTP +
Let's be honest, you pay 5000 rubles to get 50 thousand. Who will calmly hand over this money? Nobody. Very often I hear from people - "they took money and ay". You're right.
How to act when you have an insured event. It doesn't matter what you are insured against, first get out your policy (insurance contract) and read it. Believe me, some 15 minutes will save your time in the future and your nerves. If you can't figure it out, call the company's hotline, it is better from another phone, which you will not use later, ask questions to a specialist, specify the list of documents, how the policy works. Even if you are harmful, angry and psychotic, the operator will explain, clarify and try to explain to you until the very end.
You don't need to tell the truth or make up super stories. This will affect in the future. After the consultation, consider how and what to say. Very often I meet parents who place the blame on their children. The child dropped the phone, the child was pushed at school, the child ate soup and spilled it on it.
Believe me, these details are not interesting to anyone, and then they can play not in your favor.
There is a risk of external mechanical impact - it will be enough to drop the phone and crash. - Believe me, this will be a payment, not a trial of who and where pushed whom and why you did not go to the police, because a third party was involved.
"External mechanical action"- This company has its own rules, which means that a defect interferes with the operation of the device. If it is a scratch, chip or broken back panel of the phone, then you are passing by. The crack should hit both the screen and the edge of the screen. If the device fell and crashed, for example, a model that is inside the device, and the device itself is not damaged, alas, this is not an insured event.
Liquid contact. - Check with a specialist that the water from the neighbors should fill your device or you yourself can drop it into the water. Of course, the specialist will say the risk is to apply. And you do not invent things later from your neighbors. Water got in - that's it. Dropped into water, Spilled water. As they say, brevity is the sister of talent.
Theft. The hardest part. Since here it is more common to be pulled out of your pocket - which equals the phrase you lost your phone. This is not an insured event. For the reason that it is not provable. And if you use your brains, you will understand that then any fool would use this trick and get money. How to proceed in this case? Only through the courts, it is dreary, long, but sometimes insurance companies, believe me, lose and pay. And at what very often.
Do not make up rain, thunderstorms, cars. These are superfluous documents. Not one service center will establish that you smashed your iPhone with a hammer, and the insurance company records the conversations.
I do not understand what is written in my policy. - Call the hotline, consult until you understand what works and how. Better yet, from the store when you buy insurance. Sellers can pour in their ears whatever ... to sell.
Features of policies. Frequent mistakes.
The policy may not start to operate from the day of purchase, see it is written on the contract itself from what date it comes into force. If you apply before the validity of the policy, then it is clear that it has not yet entered into force and you cannot apply for it. Nobody will look for you, and will not tell you, think you want to get money. And free cheese is only available in the mouseylovka.
And note to those who shout deception. Insurance is a web, everyone is thrown off, so that someone would receive money. Believe me, a lot of people got paid.
Remember, you live in Russia, where a paper hierarchy reigns. Do not be alarmed when a pile of papers is announced to you, no less you will collect in court when you receive a refusal, because you did not think, but demanded free money.
Someday I'll get to other products. The policy is not bad for someone with children and phones that often fall and break. It is bad against theft, like others from other companies.
The main document is requested: Act of a licensed service center - There is no such thing in your city, do not despair. Any company accepts applications in a free form, do not be lazy to find the nearest one 200 km away, write an application to your company, competently, that you cannot provide not at will, but because it is very far away. Or the act is expensive, and the phone costs a penny. Ask the company to help you with your hard work, as you do not know how to proceed. Ask for a favor to make a decision without this document or to allow you to contact another service that is not licensed, but makes cheaper in your city.
Maybe my review will help someone get money. And please remember, no one will give the money right away. From this and the timing and questions and unnecessary documents. Good luck to you. And don't smash your phones or spill soups on them
Termination of any contract.
Everyone knows that a new law has been passed and the Insurance Company must terminate your contract and return your money. But not everyone knows how this law works.
You have 5 working days from the date of the conclusion of the contract (loan, box, etc.)
Conclusion of a contract - you come, buy something, you draw up a contract. Everything from this day is reported in 5 working days, for these 5 working days you must submit documents for termination. (Fill out an application, attach an agreement, a payment receipt and your details). If you have a branch in your city (check with the operator) go directly to the branch. If there is no branch, do not send by e-mail, send by registered mail with notification by mail to Russia, so that you have a document on the sending of your documents.
Breaking the boxes!
Hello dear friends again! This time I decided to tell you how to terminate the insurance contract, how to get your money back.
WITHOUT ACTIVATION
Nowadays, VTB24 sellers often sell a couple of boxes with a loan. Which are voluntary insurance, unlike credit insurance, you are not obliged to buy them and they do not affect the credit. Box data: I can do everything, I can do everything +, Live, do not grieve! Fizkult, hello, hello, neighbor!
Let's start with the fact that you were sold the product, but you want to get your money back.
DO NOT ACTIVATE THE PRODUCT. Or ask the seller if he insists on activating the product, tell him that you will activate it at home. On the same day, or up to 30 calendar days, call the SK and ask to terminate the insurance contract, since you have not activated it. Then the procedure will take less time and the money will be transferred to the account.
You will need:
Product box
Check. (If there is no receipt, contact the point of sale. Take a duplicate, slip, a document on which will be written "Product, its cost, date of purchase".
Bank details for transferring money to you.
PASSIVE ACTIVATION - STARTING ON 31 DAYS FROM THE MOMENT OF PURCHASE (NOT FOR ALL PRODUCTS)
Now let's consider another option. Your policy has BEEN ACTIVATED SELF.
There are two options for the outcome of events, either the policy acts on your property that is owned, or on your children, or on yourself.
If you have property, so do the children, and so do you. It is almost impossible to terminate the policy. Even the court will bend its line that the conditions are written on the product. Here is one option, to write a claim to the insurance company, but not with a request to terminate the contract, but with a request to answer on what conditions the termination of this contract is impossible, with a request to clarify the clause of the contract where refunds were denied upon termination of the contract and to go to court. If only you had on hand documents confirming the refusal of the UK to return the money to you.
IF NO PROPERTY, CHILDREN.
To court. You also apply to the UK on the claim form, as mentioned above.
Collect boxes, checks, passport, answers from the UK. In court, you can refer to the "Other circumstances" clause. This means that you have no property, and since you do not have property or children, then this product is not valid. You will win 100% of the court, previously the UK returned the money, but then changed her mind and began to send people to court, because less people would be involved in red tape.
Legal costs will then be paid by the UK, that is, it takes time from you. Of course, all this is terribly angry, unnerving. Have patience, my friends, you want to get your money back. By myself, I will say that the court will take you 2-3 days at most, the collection of documents is even less.
The claim is processed 15-30 business days. If the deadlines are violated, again a claim. Write, a call in court will not play a big role, and your written appeals will play into the hands.
Of course, some will say that I have to do this because of 3000 thousand?
Alas, in this case, the money cannot be returned by a scandal, there are only these options.
How to write a claim !?
Application on A4 sheet, addressed to VTB Insurance. Indicate your full name. address, contact details. Your complaints, claims, questions. Finish with a live signature and your last name and number. You photograph or scan, send to the address that the operator tells you. Question to the operator: To what address can I send a written claim. How can I clarify the status of my claim?
That's all! Later I will add other products)
Hope I could help you.
It is practically impossible to avoid mechanical influences on electrical equipment in the modern world, therefore, an assessment of resistance to the influence of external mechanical factors must be carried out. There are several ways of such verification, which are described by the authors of the material.EXTERNAL MECHANICAL IMPACT
METHODS FOR CONFIRMING THE RESISTANCE OF ELECTRICAL EQUIPMENT
Valentin Shishenin,
Doctor of Technical Sciences,
Vladimir Bakin,
Ph.D.,
Vladimir Pavlov,
Engineer, Scientific Research Center 26 TsNII MO RF
St. Petersburg
The scientific development of the problems of checking the factors of impact and vibration on various equipment was started back in the 50s – 60s of the last century. Research carried out in this area has made it possible to identify the groups of equipment that are most critical to vibration and shock loads.
Electrical equipment belongs to the group most sensitive to vibration and shock (hereinafter referred to as mechanical) loads, since it has in the structure of functional circuits automatic switches (switches), electromagnetic starters, relays and circuit breakers of various types, showing control devices (ammeters, voltmeters, etc.). These conclusions are confirmed by foreign studies.
Mechanical effects on electrical equipment are largely due to dynamic phenomena arising from the rotation and reciprocating motion of unbalanced elements and parts. In turn, low-amplitude mechanical vibrations often cause resonant vibrations of other structural elements. An additional source of mechanical influences on electrical equipment are technogenic factors, as well as external natural factors, including earthquakes. The examples of recent years confirm that there are now no places on earth where earthquakes are impossible.
Even greater potential danger for the environment and the population is distinguished by cases of malfunction and failure from mechanical effects of electrical equipment installed at hazardous industries and nuclear power plants. Therefore, higher requirements are imposed on the resistance of electrical equipment at high-risk facilities.
Test standards
According to GOST 17.516.1-90, electrical products are divided into groups of mechanical design, depending on the area of \u200b\u200bapplication and installation location. Based on this, requirements are imposed on them in terms of strength, stability and resistance to mechanical external influencing factors of various degrees of rigidity.
For hardware, instruments, devices and equipment for military purposes, the requirements for resistance to external influencing factors are put forward in accordance with GOST RV 20.39.304-98. Tests of electrical equipment for compliance with the requirements of GOST 17.516.1-90 in terms of resistance to mechanical external influencing factors are carried out in accordance with test methods in accordance with GOST 20.57.406-81 and GOST 16962.2-90. Tests of electrical equipment for military purposes for compliance with the requirements of GOST RV 20.39.304-98 in terms of resistance to mechanical external factors are carried out in accordance with test methods in accordance with GOST 20.57.305-98.
In the general case, verification of the compliance of electrical equipment with the requirements put forward can be carried out by experimental, calculated and calculated-experimental methods. Each of them has its own characteristics, advantages and disadvantages.
Experimental method
The most complete and reliable data on the strength, stability and resistance of equipment to the mechanical effect of external factors can be obtained only experimentally. Analysis of the results of tests of electrical equipment for the effect of external mechanical factors, carried out over the past 10–20 years at NRC 26 Central Research Institute, made it possible to establish the most typical failures and shortcomings.
1. Breakage or destruction of attachment points caused by:
- by cutting the mounting bolts and studs;
- deformation of support units made of profile or sheet steel;
- the appearance of cracks and destruction of the cast-iron foundation frames at the base;
- the appearance of cracks in the welded seams of the support units of the units.
- deformation of the frame, covers and doors of rack-mount and cabinet-type equipment;
- deformation of the supporting nodes of the door pillars, preventing their further fixation in the closed position;
- destruction and spalling of flange protrusions on cast-iron covers of electric motors.
- displacement of roll-out carts;
- destruction of bushing and support insulators, getinax boards and textolite enclosures;
- falling out of arc chutes, electrical measuring instruments;
- destruction of the filament of lamps in lighting equipment and apparatus;
- destruction of bearings.
Spontaneous closing and opening of the contact elements of the devices at the moment of exposure to the load can lead to the shutdown of important technical systems and disruption of technological processes.
For objective reasons, in Russia over the past fifteen years there has been a significant reduction in the number of functioning test laboratories and test centers and, as a result, the number of test facilities that reproduce mechanical, including seismic, effects.
It should also be noted that the park of testing facilities for mechanical stress is very worn out, the test benches are relatively small, and the lack of multicomponent installations.
In fact, there is no possibility of testing large-sized equipment with linear dimensions of more than 3 m and a mass of more than 3 tons for vibration and shock.
And as practice shows, unique large-sized and massive equipment, due to its inertial characteristics, tolerates mechanical stress worse and therefore needs mandatory testing for the effect of expected external mechanical factors. The same is the case with test facilities for testing for effects adequate to intense earthquakes. In the former USSR, there were five large programmed seismic platforms equipped with hydraulic drives. In recent years, seismic platforms located on the territory of the Russian Federation practically did not work, and it remains unclear what the required allocations are to restore their operability and modernization.
Calculation method
A significant disadvantage of using the experimental method is its dependence on the limited capabilities of the test equipment. Therefore, if it is necessary to assess the strength to mechanical stress of samples of electrical equipment made from materials with known characteristics, a calculation method is used. This is facilitated by the modern development of modeling and calculation methods, software and computer technology. The indisputable advantage of the calculated method for determining the strength lies in the fact that its application is not limited by the size and maximum mass of the calculated equipment. In addition, in comparison with the experimental method, the calculation has a fairly low cost.
Among the main disadvantages of this method for determining strength, the following can be emphasized:
- by calculation, it is practically impossible to assess the stability of the operation of electrical equipment during the influence of an external mechanical factor;
- it is practically impossible to confirm compliance with the requirements for strength to the effect of external mechanical factors for equipment samples with nonlinear characteristics and complex systems of electrical equipment;
- the accuracy of determining the strength depends on the adopted design model, the qualifications of calculation specialists, the software products and techniques used.
Taking into account the technical capabilities of the existing test means, testing a complex electrical system for resistance under the influence of mechanical factors may actually be unrealizable or require significant material costs, and the assessment of the resistance of the system as a whole by calculation is impossible. In this case, a computational and experimental method is used.
On a vibrodynamic stand, the cabinets were tested for resistance to sinusoidal vibration with the indicated amplitudes of vibration displacement and vibration acceleration in the range from 7 to 100 Hz. As you know, vibration tests in the range from 1 to 5 Hz are difficult due to the lack of vibrodynamic stands of the required carrying capacity. During the tests, the acceleration parameters were recorded with the help of three sensors installed in certain places of the cabinets. In parallel, design models of cabinets were developed and calculations for a similar effect were carried out.
Practical example
The task was to assess the resistance of a group of electrical equipment cabinets with a maximum dimensions of 600x800x2000 mm and a maximum mass of 250 kg to the effects of sinusoidal vibration in the range from 1 to 100 Hz, with an amplitude of vibration acceleration of 7 m / s2 from 1 to 35 Hz and with an amplitude of vibration acceleration of 10 m / s2 from 35 to 100 Hz.
After the tests, the calculated and experimental data were compared in the frequency range from 7 to 100 Hz, and a sufficient convergence of the calculation and test results was revealed. Tests have shown that the cabinets are resistant to test impacts in the range from 7 to 100 Hz. After the tests, the calculations of the cabinets were carried out on the proven design models for the effect of sinusoidal vibration in the range from 1 to 7 Hz. The kinematic parameters obtained by calculation at the set points did not exceed the motion parameters recorded at the same points during the tests. Therefore, according to the results of the computational and experimental evaluation, a positive conclusion was made about the resistance of the equipment in the range from 1 to 100 Hz when exposed to a given sinusoidal vibration.
Computational and experimental is the most universal method for determining the resistance (strength, stability) of equipment samples and their systems to external mechanical influencing factors. It combines the advantages and partially eliminates the disadvantages of the computational and experimental methods, but its application requires a sufficient amount of necessary initial and experimental data, the correctness of the methods and techniques used, and highly qualified specialists.
A few tips for manufacturers
Increasing the resistance of electrical equipment to external mechanical factors can be carried out by:
- the use of optimal circuit solutions;
- use of resistant components in equipment;
- reducing the size of products;
- rational layout and fastening of components, increasing the fill factor;
- the use of unified frames of the optimal profile;
- improvement of locking devices for doors and covers of cabinet equipment;
- devices for additional fastening at the top of the product;
- calculation of standard equipment attachment points;
- control during installation of the required tightening force of bolted connections.
1. Vibrations in technology. Reference book in 6 volumes. - T. 3. Oscillations of machines, structures and their elements. - M .: Mechanical Engineering, 1980.
2. Coloiaco A.P., Elsher E. G. Sine-beat tests verifies switchgear control equipment // IEEE Trans. Power Appar. and Syst. - 1973. - Vol. 93, N2. - P. 751-758.
3. Kirillov A.P., Ambriashvili Yu.K. Seismic resistance of nuclear power plants. - M .: Energoatomizdat, 1985.
4. GOST 17.516.1-90 “Electrical products. General requirements in terms of resistance to mechanical external factors. "
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8. GOST RV 20.57.305-98 "Test methods for the impact of mechanical factors".
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