The main contact of low-voltage circuit breaker is closed manually or electrically. After the main contact is closed, the free tripping mechanism locks the main contact in the closing position. The coil of the overcurrent release and the thermal element of the thermal release are connected in series with the main circuit, and the coil of the undervoltage release is connected in parallel with the power supply.

當(dāng)電路發(fā)生短路或嚴(yán)重過載時(shí)，過電流脫扣器的銜鐵吸合，使自由脫扣機(jī)構(gòu)動(dòng)作，主觸點(diǎn)斷開主電路。

In case of short circuit or serious overload of the circuit, the armature of the overcurrent release is pulled in to make the free tripping mechanism act, and the main contact disconnects the main circuit.

當(dāng)電路過載時(shí)，熱脫扣器的熱元件發(fā)熱使雙金屬片上彎曲，推動(dòng)自由脫扣機(jī)構(gòu)動(dòng)作，主觸點(diǎn)斷開主電路。

When the circuit is overloaded, the thermal element of the thermal release generates heat, bends the bimetallic sheet, pushes the free release mechanism to act, and the main contact disconnects the main circuit.

當(dāng)電路欠電壓時(shí)，欠電壓脫扣器的銜鐵釋放，也使自由脫扣機(jī)構(gòu)動(dòng)作，主觸點(diǎn)斷開主電路。

When the circuit is under voltage, the armature of the under voltage release releases, which also makes the free release mechanism act, and the main contact disconnects the main circuit.

（1）當(dāng)按下分勵(lì)脫扣按鈕時(shí)，分勵(lì)脫扣器銜鐵吸合，使自由脫扣機(jī)構(gòu)動(dòng)作，主觸點(diǎn)斷開主電路⑴額定電壓斷路器銘牌上的額定電壓是指斷路器主觸頭的額定電壓，是保證接觸器觸頭長期正常工作的電壓值。

(1) When the shunt release button is pressed, the armature of the shunt release is pulled in to make the free release mechanism act, and the main contact disconnects the main circuit ⑴ rated voltage the rated voltage on the nameplate of the circuit breaker refers to the rated voltage of the main contact of the circuit breaker, which is the voltage value to ensure the long-term normal operation of the contactor contact.

（2）額定電流接觸器銘牌上的額定電流是指路器主觸頭的額定電流，是保證接觸器觸頭長期正常工作的電流值。

(2) The rated current on the nameplate of the rated current contactor refers to the rated current of the main contact of the circuit breaker and is the current value to ensure the long-term normal operation of the contactor contact.

⑶脫扣電流脫扣電流是使過電流脫扣器動(dòng)作的電流設(shè)定值，當(dāng)電路短路或負(fù)載嚴(yán)重超載，負(fù)載電流大于脫扣電流時(shí)，斷路器主觸頭分?jǐn)唷?/div>