How to use a multimeter to check if the circuit is short-circuited or grounded
Jekk int trid to check for a short circuit in the circuit. First, cut off the power supply to the line, then open the load switches and use the ohm range of the multimeter to measure the resistance between the two wires. Under normal circumstances, a higher resistance is better. If it is determined jekk the circuit is grounded, the circuit is grounded, the ohm range of the multimeter can be used. Measure the resistance ta kull ċirkwit għal art. The akbar the better. It should be pointed out that using a multimeter to measure for short circuits and grounding in a circuit is inaccurate. It is also not appropriate. If the grounding or short-circuit resistance is very small, it can be detected with a multimeter. If the resistance is a multimeter. If the resistance is ssometimes larger, it should not be detected. A multimeter cannot detect it in a low voltage circuit of 380V. A 500V shaker should be used for measurement, jekk between lines or to ground. All should be above 0.38 megaohms. Otherwise, it is unqualified.
Il-metodu ta ' li tuża a multimeter biex tiskopri short circuits in a circuit. Firstly, cut off il enerġija provvista ta ' il test linja. Imbagħad neħħi wieħed tmiem ta ' il- kontroll transformer / 2c indikatur dawl , u vultaġġ transformer in iċ-ċirkwit 2c kif dawn komponenti huma konnessi direttament madwar iċ-ċirkwit Jekk mhux imneħħija , l- impedenza ta ' dawn komponenti jistgħu jaffettwaw tiegħek kejl. Some circuits ukoll have three-phase loads such as frequency converters and rectifier bridges, and these devices need to be disconnected from the circuit. Then turn the multimeter to the diode mode (buzzer mode) and measure the conductivity of the two wires being tested
Jekk l-aħmar u iswed probes of the multimeter overlap, and there is a buzzing sound or impedance display display on the multimeter, it indicates that there is a problem with the tested circuit. Normally, there is tested circuit. Normally, there is no sound and the display screen of the multimeter does not show any numerical changes. The grounding detection method for the line is also the same. This is just a conventional detection method. To be foolproof, it is aktar affidabbli to use a shaking table for detection, li should be at least greater than 0.5 megohms.
The essence of voltage is potential difference. As long as the voltage between two lines is 0, it can be measured using resistance mode:
1. Assuming there is a short circuit between line A and line B to be measured, there may be a voltage (such as 220 volts) between line A and line B to the neutral line, and the potentials on their lines are potential A and potential B. Many people first think that if they measure directly in resistance mode, they must disconnect the power supply on line A and line B separately before measuring. This idea is not wrong, but rather conservative.
2. Direttament set the multimeter to the AC voltage range, select the highest range, such as AC1000 volts, and then use the AC voltage range of the multimeter to measure line A and line B. If there is a relatively high voltage (such 200 volts) between the two lines, it can prove that potential A and potential B are not equal, that is, is, there is a voltage difference bejn potenzjal A u potenzjal B. Dawn dawn żewġ linji mhumiex ekwipotenzjali u huma mhux qosra ċirkwiti flimkien.
3. If hemm mhu le vultaġġ imkejjel bejn linja A u linja B bl użu the AC voltage range, for the sake of assurance, a DC voltage range such as 10}00 volts can be selected to measure between them, and it can be confirmed that there is no DC voltage. This can prove that the potential A and potential B are equal. Note that being being equal ma not mean that they have no voltage on the neutral line N. For example, both line A and line B have a voltage of 220 volts on the neutral line N, but the voltage between them is is also 0 volts. At this time, the smallest resistance range can be used to measure the resistance between these two lines. If it is close to 0 ohms, it means that these these żewġ linji huma qosra ċirkwiti flimkien.
4. As for jekk il-kejl is grounded, the above method can be be used for simple measurement. The idea is to understand the ground wire as a regular wire. But in general, to measure whether it touches the ground, a megohmmeter can be used to measure the insulation resistance (normalment 5 megohms for insulation), u.5 megohms for insulation), u dan time, a power outage is required for measurement.
