1. When selecting contactors, we should start from the working environment and mainly consider the following factors

①控制交流負(fù)載應(yīng)選用交流接觸器，直流負(fù)載選用直流接觸器

① AC contactor shall be selected for controlling AC load and DC contactor shall be selected for DC load

②主觸頭的額定工作電流應(yīng)大于等于負(fù)載電路的電流，還要注意的是接觸器主觸頭的額定工作電流是在規(guī)定的條件下（額定工作電壓、使用類別、操作頻率等）能夠正常工作的電流值，當(dāng)實(shí)際使用條件不同時(shí)，這個(gè)電流值也將隨之改變。

② The rated working current of the main contact shall be greater than or equal to the current of the load circuit. It should also be noted that the rated working current of the main contact of the contactor is the current value that can work normally under the specified conditions (rated working voltage, use category, operation frequency, etc.). When the actual use conditions are different, this current value will also change.

③主觸頭的額定工作電壓應(yīng)大于等于負(fù)載電路的電壓。

③ The rated working voltage of the main contact shall be greater than or equal to the voltage of the load circuit.

④線圈的額定電壓應(yīng)與控制回路電壓一致

④ The rated voltage of the coil shall be consistent with the voltage of the control circuit

接觸器選擇的具體步驟

Specific steps for contactor selection

①選擇接觸器的類型，需要根據(jù)負(fù)載種類選擇接觸器的類型

① To select the type of contactor, you need to select the type of contactor according to the load type

負(fù)載種類：一類、二類、三類、四類

Load type: class I, class II, class III and class IV

標(biāo)記名：AC-1、AC-2、AC-3、

Tagnames: ac-1, AC-2, AC-3

控制對(duì)象：無感或徵感負(fù)載、異步電動(dòng)機(jī)的啟動(dòng)和停止、籠型異步電動(dòng)機(jī)的運(yùn)轉(zhuǎn)和運(yùn)行、籠型異步電動(dòng)機(jī)的啟動(dòng)、反接制動(dòng)、反轉(zhuǎn)和點(diǎn)動(dòng)，

Control objects: non inductive or characteristic load, start and stop of asynchronous motor, operation and operation of cage asynchronous motor, start, reverse braking, reverse rotation and inching of cage asynchronous motor,

②選擇接觸器的額定參數(shù)

② Select the rated parameters of the contactor

根據(jù)被控對(duì)象和工作參數(shù)，如電壓、電流、功率、頻率等，確定接觸器的額定參數(shù)。

Determine the rated parameters of the contactor according to the controlled object and working parameters, such as voltage, current, power, frequency, etc.\

（1）接觸器的線圈電壓，一般應(yīng)低一些為好，這樣對(duì)接觸器的絕緣要求可以降低，使用時(shí)也比較安全。當(dāng)控制電路簡(jiǎn)單，使用電器比較少時(shí)，可直接選用380V或220V的電壓。若電路復(fù)雜。使用電器的個(gè)數(shù)超過5個(gè)時(shí)，可選用36V或110V電壓的線圈，以保證安全。但為了方便和減少設(shè)備，常按實(shí)際電網(wǎng)電壓選取。

(1) The coil voltage of the contactor should generally be lower, so that the insulation requirements of the contactor can be reduced and it is safer to use. When the control circuit is simple and few electrical appliances are used, 380V or 220V voltage can be directly selected. If the circuit is complex. When the number of electrical appliances exceeds 5, 36V or 110V coils can be selected to ensure safety. However, in order to facilitate and reduce equipment, it is often selected according to the actual grid voltage.

（2）電動(dòng)機(jī)的操作頻率不高，如壓縮機(jī)、水泵、風(fēng)機(jī)、空調(diào)等，接觸器額定電流大于負(fù)載額定電流即可。

(2) The operating frequency of the motor is not high, such as compressor, water pump, fan, air conditioner, etc. the rated current of the contactor is greater than the rated current of the load.

（3）對(duì)重任務(wù)型電動(dòng)機(jī)，如機(jī)床主電動(dòng)機(jī)、升降設(shè)備等，選用時(shí)接觸器額定電流大于電動(dòng)機(jī)的額定電流

(3) For heavy duty motors, such as machine tool main motors and lifting equipment, when selected, the rated current of the contactor is greater than the rated current of the motor

（4）對(duì)特種用途電動(dòng)機(jī)。經(jīng)常運(yùn)行于啟動(dòng)反轉(zhuǎn)的狀態(tài)時(shí)，接觸器大致可按電壽命及啟動(dòng)電流選用，可選CJ10Z、CJ12、

(4) For special purpose motors. When it often operates in the state of start reversal, the contactor can be selected according to the electrical life and starting current, and cj10z, cj12

（5）用接觸器對(duì)變壓器進(jìn)行控制時(shí)，應(yīng)考慮浪涌電流的大小。例如電焊機(jī)，一般可按變壓器額定電流的2倍選取接觸器，如CJT1、CJ20等。

(5) When controlling the transformer with contactor, the magnitude of surge current shall be considered. For example, for electric welding machines, contactors can generally be selected according to twice the rated current of the transformer, such as cjt1, cj20, etc.

（6）接觸器的額定電流是指接觸器在長期工作下的最大允許電流，持續(xù)時(shí)間≤8H，且安裝于敞開的控制板上，如果冷卻條件較差，選用接觸器時(shí)，接觸器的額定電流按負(fù)載額定電流的1.1-1.2倍選取。

(6) The rated current of the contactor refers to the maximum allowable current of the contactor under long-term operation, with duration ≤ 8h, and installed on the open control board. If the cooling conditions are poor, when selecting the contactor, the rated current of the contactor shall be selected according to 1.1-1.2 times of the rated current of the load.

（7）選擇接觸器的數(shù)量和種類。觸頭的數(shù)量和種類應(yīng)滿足控制電路的要求。

(7) Select the number and type of contactors. The number and type of contacts shall meet the requirements of control circuit.