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cpweek Tech blog

The ACB Product Selection and Engineering Design Points

04:38, 19/4/2013 .. 0 comments .. Link
Low-voltage circuit breaker is mainly used in the civil design circuit overload, short-circuit, over-current, voltage, undervoltage, ground leakage, dual power automatic switching and infrequent start motor protective, operational and other purposes, their choice The principle addition to complying with the basic principles of the use of environmental characteristics of the low voltage electrical equipment shall also consider the following conditions:

1) The rated voltage of the circuit breaker should not be less than the rated voltage of the line;
2) the rated current of the circuit breaker rated current and over-current release is not less than the calculated current of the line;
3) circuit breakers rated short-circuit breaking capacity not less than the maximum short circuit current in the line;
4) Select the type distribution circuit breakers need to consider the with short delay short-circuit breaking capacity and delay protection level;
5) the circuit breaker undervoltage release voltage rating equal to the rated voltage of the line;
6) When used for motor protection, the circuit breaker should be considered the starting current of the motor and make it in time from the action; design calculations, see the industrial and civil power distribution design manual;
7) breaker selection should also consider the selective coordination of circuit breakers and circuit breakers, circuit breakers and fuses.

(1) circuit breakers and circuit breaker with instantaneous tripping action should be considered superior circuit breaker value should be greater than the lower circuit breaker outlet end of the maximum prospective short circuit current, the circuit components of the impedance value of the difference in the two at the circuit breaker short circuit small, so that the short-circuit current value is not very different, you the superior breaker can choose with short delay release.
(2) limiting the short-circuit current is greater than or equal to the instantaneous trip setting value, the circuit breaker will trip in a few milliseconds, so the lower-level protection of electrical circuit breaker suppliers should not be selective protection requirements.
(3) with a short time delay circuit breaker, when the time limit for setting a maximum delay, breaking capacity decreased, so the in selective protection circuit, consider the choice of circuit breaker breaking capacity should meet the requirements of short delay .
(4) It should also consider the the superior circuit breaker short-circuit delay return characteristics with the lower circuit breaker operating characteristics curve of time should not intersect the characteristic curve of the temporal characteristics of the short delay between the curves should not intersect.
(5) should be used in conjunction with circuit breakers and fuses the upper and lower mating An seconds the safety breaker second characteristic curve with fuse should be compared to the characteristic curve to make in the case of short-circuit current occurs, a protective selective .
(6) circuit breakers for the protection of distribution lines, should be chosen with the long delay overcurrent trip circuit breaker, when the end of the line single-phase short-circuit, short-circuit current is not less than the circuit breaker instantaneous or short delay overcurrent release setting current of 1.5 times. [1]

CW1 Series Intelligent Universal Circuit Breaker has the following main features:
1, small size, compact structure
2, in strict accordance new national standards GBI4048.2 of-2001 manufacturing production
3, to meet the isolation requirements
4, has a high thermal-stable
5, high breaking, zero-arcing, to meet the distribution system the various needs of
6, with high electromagnetic compatibility
7, the circuit breaker can be motivated to line or line under the

1.2 Scope

CW1 series intelligent universal circuit breaker is suitable for AC 50Hz. Voltage up to 690V, current up to 5000A in the distribution network, mainly used to distribute electric energy and the protection of lines, electrical equipment against overload, under voltage, short circuit, ground fault hazards. Circuit breaker with precise selective protection and multi-function intelligent controller, especially for the need to improve the reliability of power supply to avoid unnecessary blackouts distribution network. Circuit breakers rated working voltage of 400V, 690V, rated insulation voltage 1000V, rated current of 630A to 5000A.

Rated current 1000A and below the circuit breaker, but also in AC 50HZ, 400V network as motor overload, under voltage, short circuit and ground fault protection for the motor infrequent start with.

1.3 overall structure

CW1 Series Intelligent Universal Circuit Breaker fixed and drawers of the points, the fixed circuit breaker body into a dedicated drawer seat drawer. Body contact system, arc system, the operation was Gamaliel, current transformers, intelligent controller and auxiliary switch, the secondary circuit terminals, undervoltage release and other components; drawer seat by the left and right side plates with rail, chassis and bracket.

Mobile Phone Lithium Battery Correctly Use Method

04:46, 20/3/2013 .. 0 comments .. Link

First, The cell phone lithium battery

Phone lithium battery cover up and down by the plastic shell, lithium batteries, protection circuit board (PCB) and resettable fuse (polyswitch). Some manufacturers also configure the NTC, identifying resistance, vibration motor or charging circuit and other components.

The function of each part are as follows:
(1) lithium batteries: rechargeable discharge source.
(2) protection circuit board (PCB): prevent battery overcharge and over discharge short circuit.
(3) resettable fuse (PTC): positive thermistor play high-temperature protective effect is double protection after the failure of the protection circuit board.
(4) recoverable fuse (NTC): Negative thermal resistance of the battery internal temperature sensors play a low-temperature protection.
(5) identify resistance: to identify non-original battery original battery can not be used

The batteries are very important, and the movement has several levels, Class A batteries, B grade batteries.

Second, Phone lithium battery charge and discharge the right way

Phone lithium battery charging correct way now the phone with a lithium-ion battery, so there is no memory effect, do not need to activate the charging does not require like Nickel electricity as red more than 12 hours, and only need to charge about four hours for the first time, ion battery life relationship only with the number of chargings, lithium ion batteries can be charged to about 1000 times. The standby time and usage. But, said selling phone in front of three charging time to reach 12 hours. In the end how is it?

The phone battery is the source of energy, that is, the power of the phone, the battery-powered, mobile phone is a scrap iron, a high-capacity, high-performance battery, not only can give the phone a long time endurance, but also can protect your phone circuit, making phone capable of a prolonged high efficiency work, otherwise likely to cause the device to unexpected damage. For our players, the performance of the battery when the factory had already been characterized, the size of its power, performance, good or bad, are determined by the battery itself, in this regard, we can not be man-made changes, but This is not to say that we get the battery after it it it must not be done. Mobile phone use are lithium-ion rechargeable batteries, use stored electricity runs out and needs to be recharged before supplemental power. Do not underestimate the charge of this part, a good charger and correct charging method, you can keep the standby time of the battery for a long time, but also can extend the battery life. Further step on the phone, you can also play a protective role. About how to charge, often there will be players in the forum asked, after a period of time to the actual use and reference, I summed up the following points:

1. How to charge for a new battery
In the use of lithium batteries, it should be noted that the battery placed for some time after you go to sleep, lower than normal capacity, the use of time has also come to shorten. However, lithium batteries can easily activated through 3-5 times the normal charge-discharge cycles the battery can be activated to restore normal capacity. Because lithium own characteristics, its decision is almost no memory effect.

For lithium battery "activate" problem, many say: charging time must be more than 12 hours, repeated three times, in order to activate the battery. This "three times before charging to charge more than 12 hours", obviously from the nickel battery (such as nickel cadmium and nickel metal hydride) inherited from the argument. Therefore, this argument can be said that the beginning of miscommunication. Lithium and nickel battery charge and discharge characteristics of a very big difference, and can tell you that very clear, I looked all serious formal technical information stressed that the charge and discharge lithium batteries, especially lithium liquid ion batteries can cause great harm. Charge and therefore the best charge in accordance with the standard time and standard methods, in particular for not more than 12 hours of super-long charge. Typically, the statement introduced mobile phone charging method is suitable for the mobile phone standard charging method.

In addition, the lithium battery cell phone or charger after the battery is fully automatically stop charging and there is no electricity nickel charger for 10 hours so-called "trickle" charge. In other words, if your lithium batteries in full, on the white charger is also sufficient. And we can not ensure the battery charge and discharge protection circuit features and never change the quality of safety, so your battery will be long-term in a dangerous brink. This is another reason to charge against the chief.

In addition, on some phones, charging more than a certain amount of time, if not remove the charger, then the system not only does not stop charging will start to discharge - charge cycle. Perhaps the makers of this approach has its own purpose, but obviously in terms of the life of the battery and cell phone / charger is unfavorable. The same time, long charging would take a very long time, often at night, while the situation of China's power grid, the higher voltage of the night in many places, but also volatile. As already said, the lithium battery is very delicate, more poor than nickel in the electric charge and discharge resistance fluctuations, so this brings additional risk.

In addition, another aspect that can not be ignored is the lithium battery manufacturer is also not suitable for over-discharge, over-discharge of lithium batteries is also very unfavorable. This leads to the following questions.

2. Normal use should start charging
In our forums, can often see this argument, because of the limited number of charge and discharge, the cell phone battery power should be used up as much as possible to recharge. But I'm looking for

Experimental table to a lithium-ion battery charge and discharge cycles, the cycle life data are listed as follows:
Cycle life (10% DOD):> 1000 times
Cycle life (100% DOD):> 200 times

3. Phone lithium battery the correct way
a. In accordance with the standards of the time and procedures for charging, even before the three to do so;
b. When the phone battery is too low to prompt should start charging as much as possible in a timely manner;
c. The lithium batteries activation does not require special methods in normal cell phone use lithium batteries will naturally activate. If you insist on spreading the three previous 12-hour long activation charge "approach, and in fact there will be no effect.

Therefore, the practice 12 hours long pursuit charging and phone lithium batteries used in automatic shutdown, are wrong. If you previously is wrong to say do

Ask you to correct them in time, perhaps not too late.

Of course, in the case of a good quality phone and charger to protect themselves and control circuit, the protection of the lithium battery or fairly guaranteed. So understanding is the focus of charging rules, in some cases, also can make some concessions. For instance, you find that the phone must be charged before you sleep at night, you can also start charging at bedtime. The crux of the matter, you should know what is the correct approach, and do not deliberately do the wrong to say.

Phone lithium battery charge and discharge is particular about some brand batteries phone battery charge and discharge times more can be done.

4. Use lithium batteries observe the fire

Many people may be from the phone become familiar with lithium batteries. In fact, it is used in many home appliances. Needless to say, the lithium battery efficient, light body, and so on merit it quickly promote the use of open. But, you know, careless use, it also will make you mess with the "fire" upper body?

Lithium battery body is light, efficient, low temperature resistance (-40 ℃), etc., 0.3mm thick, stamp-sized lithium batteries can be used continuously for more than five years, are being phased out in recent years active alkaline dry batteries and manganese batteries, widely used in many high-end appliances and mobile phones.

Lithium is different from the present use of manganese batteries and alkaline dry batteries of the zinc chloride and potassium hydroxide aqueous electrolyte, it is using the organic solvent. The lithium battery cathode with manganese dioxide, lead fluoride, thionyl chloride, and other materials. Compared to the anode of a lithium metal foil anode use of zinc chloride with the general battery, the ionization tendency is strong, positive and negative voltage difference is large, thereby improving the work efficiency of the lithium battery.

However, lithium batteries are often in the course of fever, burning phenomenon, the light affect host use severe cases, cause a fire also burned host. It is reported that the Japanese multi-causes of lithium battery fever burning home fires caused by accidents that have occurred in recent years.

Fever, lithium batteries then why will burn it? Original lithium battery materials in contact with water, can occur in a violent chemical reaction and release a lot of heat to cause fever, burning phenomenon. Manganese dioxide lithium battery cathode, only to dip a small drip can fever phenomenon. Release heat, thionyl chloride lithium battery contact with water to produce hydrochloric acid and sulfur dioxide at the same time, several factors make lithium batteries become "fire" in the life, people must pay attention to when using lithium batteries waterproof, anti-wet.Should be removed after the closure of the various hosts, the lithium battery in a dry, low temperature at the proper custody, in order to prevent and avoid accidents caused by home fires due to improper use lithium battery.

Lithium batteries and cell phone batteries in the process of expansion and analysis:

The battery with a long time under normal circumstances is not expand, the reasons for the expansion of the battery is the result of long charging time. It does not affect the use of just the standby time is shorter and shorter. Battery heat expansion reasons:

a. Mobile phone in the standby power consumption is very small, which means that its battery equivalent load resistance, the discharge current is very small so the battery does not heat, the internal friction of the battery power is very small.
b. Mobile phone in standby power consumption calls or game, That is the the battery equivalent load resistance is small, the work is a high-current discharge. Battery after release the part of the power, the resistance increases, however, the phone requires the current can not be reduced, then a considerable part of the energy consumed in the internal resistance of the battery, resulting in battery heat, discharge acceleration, battery Using the time will be quickly reduced.

The above is the mobile phone battery in the long-term use may have a fever of reason.

5. Mobile phone battery heat hazards and solutions

a. Cell phone battery prolonged fever will cause the phone internal mechanical heating, allowing the phone to restart or hang up the phone call.
b. Cell phone batteries prolonged fever will increase in the heat of the battery itself, if it is sealed (NOKIA like is not sealed, directly to the battery loaded) battery will be dramatic expansion of its internal air, leading to the battery as projections serious cause the battery to explode.
c. Cell phone batteries heat will accelerate the aging process of the phone itself for a long time, and shorten its life.

These are mobile phone batteries prolonged fever harm to the phone.

The solution:
1. Phone battery has been charged drum up solutions. Is the first find the cell gap with your fingers (mobile phone battery on the back near the phone charge electrode party, pressed a little soft), used for the poke a small hole, so that the air inside ran out on the line.
2. Buy a battery.



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