Home > News

Basic Circuit Law Of Explosion-Proof Distribution Box

Apr. 11, 2019

Explosion Proof Cable Gland supplier would like to share with you.

According to the two-part ohm law, when the voltage U is applied at both ends of the conductor whose resistance is R in the explosion-proof distribution box, the current I flows through the conductor. The connection between the three quantities of voltage, current and resistance was first revealed by the German physicist ohm in 1827. Ohm pointed out that the strength of the current in the conductor is proportional to the voltage at both ends of the conductor and inversely proportional to the resistance of the conductor. This is known as ohm's law, which is one of the most fundamental laws of circuits and has wide application in practice. However, the ohm's law is usually called the ohm's law of partial circuits because it is the result of a discussion of the whole closed circuit without a part of the power supply. It can be represented by the formula I=U R.

                                                      Industrial Cable Gland

According to the formula of ohm's law of partial circuit, the third quantity can be calculated as long as two of the three quantities of current, voltage and resistance are known. In order to measure the resistance, the "volt-ampere method" is commonly used in engineering (that is, add a constant current voltage at both ends of the resistance and use a voltmeter and an ammeter respectively) to measure the voltage and current, and then calculate the resistance value according to the ohm's law formula. Full circuit ohm's law this circuit consists of an internal circuit (the circuit inside the power supply) and an external circuit (the load resistance). Internal circuit and external circuit constitute the whole circuit. The experimental results show that in a closed circuit with only one power source and no branches, the current is equal to the ratio of the electromotive force of the explosion-proof distribution box to the resistance of the inner and outer circuits. This conclusion is called the ohm's law of the whole circuit and is expressed by the formula I=E (R+ R).

Industrial Cable Gland tells you that the following three working states of the circuit are analyzed according to ohm's law of the whole circuit: load state, open circuit state and short circuit state. 1. Load status: when the load resistance R and the power supply are connected, the power supply outputs current I and power P to the load. 2. Open circuit state: when the external circuit is empty, the resistance of the external circuit is infinite for the power supply, so the current in the circuit is equal to zero. According to formula U= e-ir, U=E can be obtained, that is, when the circuit is open, the terminal voltage of the circuit is numerically equal to the electromotive force of the power supply. Since the power supply current to the external circuit is zero when the circuit is in the open state, the power supply does not output electric energy to the external circuit. 3. Short circuit status: when the external circuit resistance R gradually decreases, the current I in the circuit will gradually increase; When R=0, the circuit current reaches the maximum value, which is called short-circuit current I, and the working state of the circuit is called short-circuit state. In the case of short circuit, since R=0, the voltage drop of short circuit current on R is U=0, and the electromotive force of the power supply falls on the resistance. Short circuit a serious accident, should try to avoid; Short circuit when the short circuit current I is very large, it may make explosion-proof distribution box power supply and circuit suffer mechanical and thermal damage or damage.