In recent years, along with the deepening of the socialist market economy, the product of the competition is increasingly fierce. Some appliances manufacturers selling products to promote, in the sample or any regulations on the product specification does not conform to the scientific and standard of quasi things rather than the technical performance parameters, thus caused confusion. Does the reason, one is for those who do not have a true understanding of the meaning of the parameters Second parameter meaning is clear, but in order to make the user feel superior products than others, to the fuzzy concept set high promotions, whether it's the kind of situation, is not serious, irresponsible. In order to clarify the problem, we will be effected according to the national and international current standards to describe the meaning of the electrical parameters, so as to radically. The rated working voltage electrician term low voltage electrical appliances (GB/T2900.18-92) of the rated voltage is defined as: "under prescribed conditions, to ensure the working voltage of electric equipment to work normally." The rated working voltage of our country and the world more than 30 countries is 220/380 v ac 50 hz, more than 10 countries such as Britain, Australia is 240/415 v ac 50 hz, Bangladesh, India, Malaysia, Pakistan, Singapore, etc are 230/400 v ac 50 hz. The 127/220 v, etc. Kinds of IEC publications 38, given that the voltage is too much, the trade and exchanges, and suggested that the standardization of the countries adopting unified 230/400 v voltage (molecules as the phase voltage, the denominator for the line voltage), but this kind of reform, broad, is a vast engineering system, so the world still continue to use the original voltage system.
Since our country is 220/380 v is impossible to appear the working voltage of 400 v. But there are a number of manufacturers of short circuit in the sample, it's short circuit breaking capacity column was marked the rated voltage of 400 v, in short circuit breaking current situation, let users think it is higher than 380 v (if a single look from digital, 400 v is higher than 380 v nature a lot). This dial high working voltage behavior if not interested in confusion, is a kind of cognitive misunderstanding. Circuit breaker during short-circuit breaking test and overload operation performance test, stipulate that the test voltage is 1.05 Ue, someone on the basis of understanding of 1.05 X380 = 400 v. Actually here is 1.05 times the Ue power frequency recovery voltage (steady recovery voltage). GB/T14048.1 rules of test parameters, voltage Ue tolerance is + 5%, the power grid voltage fluctuations can be 0 ~ 5%, the range of 380 ~ 400 v, and restore power frequency voltage is 1.05 times the Ue, Ue including the fluctuation range of the upper limit (maximum). Another misconception is that the general to the user's 10/0.4 KV transformer is low pressure ratio, that is, the side of the transformer voltage is 10 KV, and vice side (to the user) is 0.4 KV, which is 400 v, so the circuit breaker product rated voltage 400 v. This is fallacious. Deputy no-load voltage of 400 v is on the side of transformer. Deputy should consider when calculating load voltage winding the internal voltage drop, voltage value of about 5%. So the actual load voltage is 380 v 0.4. For transformer (or generator), can be said of its rated voltage with no-load voltage, and electrical equipment (including switch electrical appliances) rated voltage, the correct understanding and performance evaluation can only be actually load voltage. GB156-93 "standard voltage standard for three phase four wire system or communication system and the electrical voltage set for rated voltage regulation is: 220 v, 380 v, 660 v... . Standard to the rated voltage of the generator and the rules, they are: 230 v, 400 v, 690 v... . Standard also stipulates: "the electric equipment of form a complete set with generator outlet end, rated voltage, rated voltage of the generator can be used in the specific provisions in the product standard." And circuit breaker in our country now seems to have not can matched with generator (or transformer) outlet end.
To sum up, the product of the rated voltage is 400 v or 690 v is not correct. On GB/T1900.18 rated insulation voltage to the rated insulation voltage is defined as: "under prescribed conditions, which is used to measure electric equipment and components of different potential part of the dielectric strength, standard voltage value of clearance and creepage distance. Unless otherwise specified, the ratio of the maximum rated working voltage of the electrical appliances." Equivalent the IEC947-1 (1) 1998 GB/T14048.1 low voltage switchgear and control equipment general part emphasized the insulation coordination system, thus appliances used in the condition of power system is: the rating of the electrical insulation voltage should be higher than or equal to the rated voltage of the power system. (abbreviated) (slightly) from the provisions of the standard to measure, a electrical products if there is a variety of working voltage value, such as 380 v (most of the product of the voltage level) and 660 v (often used in the mine), is the rated insulation voltage can be classified as 660 v. The rated insulation voltage calibration, in according to the grades of products for pollution (circuit breaker is commonly 3) and its insulation parts of CTI value (compared to electrical leakage index) (the CTI value determines the category of the insulating material, is divided into four) I, II, IIIa, IIIb, to determine the minimum creepage distance of the products. For example, the rated insulation voltage is 660 v, the pollution level 3, for material group IIIa, IIIb, under long-term voltage electrical appliances for the minimum creepage distance 10 mm. Electrical appliances can this value to design the creepage distance of each insulation parts without the need for any to improve its insulation voltage rating.
Now some circuit breaker manufacturers, in order to improve competitiveness, according to his own rated insulation voltage is 800 v, 660 v high a level than the somebody else, and the circuit breaker rated the highest is 660 v, completely unnecessary than the high. And there are two things can't be ignored, the rated insulation voltage is high, the creepage distance will require more, if pollution levels, insulating material group are constant, the Ui (rated insulation voltage is 800 v, the minimum creepage distance should be 12.5 mm, more than when the Ui = 660 v 2.5 mm; Second, according to the requirements of circuit breaker product standards, in the overload operation performance and short circuit breaking capacity, must be verified pressure (pressure) power frequency, the voltage applied to 2 times the rated insulation voltage, Ui = 660 v, 1320 v voltage, Ui = 800 v voltage value must be increased to 1600 v, is actually increased the burden. But the most important still is the experimental values, the surface pressure regularly Ui = pressure value is 2500 v, 660 v, 1 min, Ui = 800 v, the voltage value is 3000 v. So the sort of meaningless blazonry, seeking truth from facts, a bother yourself. GB/T14048.1 regulation: "the expectations for for insulation fault must attach much importance to the serious consequences of site (such as the installation type VI or used for the large capacity power supply system or requirement) with isolation function of electrical appliances, insulation should be higher than the rated voltage of the voltage grade of creepage distance; suggest the rated insulation voltage generally improve the R10 priority coefficient of two voltage levels and above." R10 priority coefficient is 1.25. First voltage is 800 v, 660 v above the second voltage is 1000 v. , according to the provisions of the above, we should take 1000 v and 660 v pollution levels and the same material group, the creepage distance should be not less than 16 mm, but because of molded case circuit breaker is a wide choices to protect (no three protection), plus they rated current under 800 a and generally, they are not suitable for installation of class IV (power level) and the large capacity power supply system, visible from the Ui is greater than 660 v is no practical significance but increase the waste and trouble.
3, about the working current of auxiliary contacts as auxiliary contacts (or auxiliary switch) micro switch, it has two current parameter, one is the conventional thermal current, one is the working current. There are different kinds of working current and conventional heating power is only one. GB/T2900.18 to conventional heating power supply current is defined as: "under prescribed conditions of the experiment, the switch electrical appliances under 8 h duty, parts can load when the temperature rise shall not exceed the limit value of maximum current." And its working current is controlled by its electromagnet in the closed state of the load function to decide. So convention thermal current and working current are two different concepts. GN14048.5-93 "low-voltage switchgear and control equipment and electrical control circuit switching element in the first part of the electromechanical control circuit electrical appliances" in the appendix C "some auxiliary contact nominal rating category, for example," in the list of currently used 15 and more AC - DC - 13 action current, AC - 15 categories, auxiliary contact Ith = 2.5 A, control electromagnet closed state power (capacity) of 180 va, Ith = 5 a, the control power of 360 va, Ith = 10. A, control power to 720 va; DC - 13 (DC) Ith = 1 A, control power for 28 w Ith = 2.5 A, control power is 69 w, Ith = 5 A, control power is 138 w, Ith = 10. A, control power is 275 w. According to the control of the electromagnet load power, and the micro switch (auxiliary contacts) voltage value, it can calculate the working current of the Ith = 3 A, for example, can be reference to the control power of the Ith = 2.5 A, for AC - 15, the control power of 180 va (conform to AC - 15 is used to control more than 72 va communication electromagnet load regulation), va / 380 v = 0.47 A, 180, 180 va / 220 v = 0.81 A, the auxiliary contact action under 380 v and 220 v voltage current Ie; Again such as DC - DC electromagnet (control), Ith = 2.5 A, control of the electromagnet capacity (power) is 69 w, 69 w / 220 v = 0.31 A, 69 w / 110 v = 0.63 A, the auxiliary contact under 220 v and 110 v working current, determine the working current of auxiliary contact is very important, because the electricity performance of auxiliary contact experiment, abnormal through and breaking capacity experiment are associated with the value of Ie Ie in big or small do not accord with the requirement of the product.
Refer to the domestic market is still quite a percentage of molded case circuit breaker and the other two universal type circuit breaker industry standard revision in 1997, was found on the provisions of the rated working current of the auxiliary contact is very chaotic, also does not conform to the national standard of categories. Such as a circuit breaker rules Ith respectively 1 a, 3 a, 6 a. And working current when AC380V Ie 0.3 A, 0.4 A and 3 A (they are all AC - 15 categories), control of AC electromagnet in A closed state power, according to the calculated respectively 114 va and 152 va and 1140 va. In DC220V, Ie were 0.15 A, 0.15 A and 0.2 A, is the power of dc electromagnet 33 w, 33 w and 66 w, respectively. Apparently GB14048.5 standards are not complied with. The other two universal type circuit breaker through regulation, AC electromagnet power for 300 va, DC electromagnet for 60 w power, it is in use the old standard of AC and DC - 11-11, but the AC and DC - 11-11 command to cancel as early as 1993, to paraphrase is not reasonable. More than 3 points question may not entirely correct, experts hope that point.
With relevant standards and their interpretation is as follows:
The GB/T3367.9-1984 railway locomotive nomenclature Traction electric equipment terms"
"28.31 interlocking contactor (locking contact)
To prevent an electrical action of electrical contact under certain conditions. "
The GB/t. 10-1984 railway locomotive nomenclature The name of traction electric equipment
"10.3.12 auxiliary contacts (auxiliary contact)
10.3.13 interlocking contactor (locking contact)"
The GB/T2900.18-1992 electrical terms low-voltage electrical appliances"
"5.3.1 contact system
Including dynamic contact, static contact and the conductor components as well as the elastic element, fasteners, such as pieces of insulation of all structure parts of electrical components.
5.4.6 interlock
Between a few switch electrical appliances or components, in order to ensure the switch electrical appliances or its components in accordance with the provisions, the sequence of actions or prevent misoperation and mechanical interlock mechanism.
5.3.1.8 auxiliary contact
Pick up in the auxiliary circuit of switch electrical and electrical operation in mechanical way by the switch contact. "
The GB/T2900.36. J - 1996 electrical terms Electric traction."
"25.13 interlocking circuits (interlock circuit)
Connection circuit of mechanical, electrical or other device, such as after the working state of the auxiliary contacts to make a device depends on one or more devices working condition and location.
30.31 interlocking contactor (cocking contact)
To prevent an electrical action of electrical contact under certain conditions. "
Comprehensive criteria above you can see, in addition to the names of GB/T3367.10, interlocking contactor and auxiliary contacts at the same time as the entry, several other standards in both choose one entry, shows both express things are the same, but the emphasis on the characteristics of different. Auxiliary contacts highlights the difference between it and the main contact, don't put the auxiliary contact again in the two standards of terms as in the other articles used in the word "auxiliary contacts", is the emphasis on the difference between it and the main contact. Interlocking contactor to emphasize its effect. Auxiliary interlocking did not appear as entries in these standards. Suggest using "interlocking contactor" said separate electric interlocking contact and contact the auxiliary contact of electric interlocking role, "interlocking contactor system" said interlock contact related system as the main terms, the emphasis and the main contact to distinguish when using "auxiliary contacts. When there is no need to no longer use "auxiliary interlock".
5., power frequency voltage withstand voltage, high voltage, insulation dielectric strength and power frequency withstand voltage
This a few terms and professional books, technical documents, procedures and other written materials are in, is said to experimental conditions, cause no breakdown of power frequency sine voltage RMS.
The provisions of the relevant national standards, industry standards are as follows:
The GB/T2900.25-1994 electrical terms rotating machine"
"6.2.50 withstand voltage test (High - volgage test), Dielectric strength test (Dielectric test)
Places high voltage on the insulation test to determine whether the dielectric strength to meet the requirements. "
The basic technical conditions GB/T755-1987 rotary motor,
"6.2 the insulation withstand voltage test".
The TB/T2436-1993 railway locomotive moving vehicle motor general technical conditions"
"7.2 motor insulation dielectric strength
Motor winding on the stand and winding each other should be able to withstand insulation withstand voltage test for 1 min. "
The TB/T1333-1996 locomotive electric basic technical conditions"
"5.12.3 power frequency withstand voltage
Appliances should be able to withstand test of power frequency voltage (RMS) 1 min without breakdown and flashover phenomenon. "
The GB/T1333-1996 locomotive electric basic technical conditions"
"5.12.3 power frequency withstand voltage
Appliances should be able to withstand test of power frequency voltage (RMS) 1 min without breakdown and flashover phenomenon. "
The GB/T2900.18-1992 electrical terms low-voltage electrical appliances"
"6.1.67 power frequency withstand voltage
Under specified test conditions, not cause breakdown of power frequency sine voltage RMS. "
The GB/T163185-1996 rotating traction motor basic test method"
"17 withstand voltage test
Motor under the thermal state, according to the test voltage specified voltage withstand test, for 1 min, insulated should not be breakdown. Test voltage frequency 50 hz, waveform for practical sine wave. "
The GB/T2900.15-1997 electrical terms transformer transformer voltage regulator reactor"
"2.1.48 rated insulation level (rated insulation level)
The insulation of the transformer class electrical equipment, designed to a set of test voltage under specified conditions.
Note: the test voltage, respectively is:
A) rated lightning shock and rated short circuit power frequency withstand voltage
B) rated lightning strike and the rated impulse withstand voltage operation ".
The title of a few words, "pressure" is a standard language, written language has been basically no, the rest of the few are available in the standard. Most of these standards is a few years ago in order to in line with international standards and to adopt imported, which is translated directly. As with the English words are used in different countries or organizations, also have a plenty of different people will be the same in English translated into different Chinese. In our text data, however, use different terms for the same thing is wrong, because it is bad for technical communication and concise, clear words. Have power frequency withstand voltage and impact of two terms mean power frequency voltage resistance are accurate enough. The possibility of power frequency withstand voltage has resistance to pressure. Insulation dielectric strength is the purpose of withstand voltage test, is not straightforward. In the power frequency withstand voltage "resistance" and "with" have to repeat. Suggest a unified labor frequency voltage withstand to represent places 50 hz sine wave on the insulation, high effective value is higher than normal value work rule 1 min without breakdown of flashover voltage withstand voltage test to determine whether the insulation dielectric strength meets the requirements.
Into terms using standard lag is the cause of irregularities and standardized consciousness is not strong. With the development of the socialist market economy and world economy integration, the noun terminology standardization will appear more important and urgent.