How to measure circuit continuity with a multimeter
1, Voltage measurement method.
Firstly, power on the control circuit and adjust the multimeter gear switch to AC voltage level 750V. Referring to the circuit schematic, one probe of the multimeter remains on line 9, while the other probe measures lines 8-7-6-5-4-3. When the switch is not closed, the two probes are in phase and the voltage is 0V. When measuring lines 2-1, the two probes are in different phases and the voltage is around 380V. This is the normal state of the circuit. If the voltage value of any line or point does not match the circuit schematic during the measurement process, in most cases, the point with the wrong voltage value is the fault point!
2, Resistance measurement method.
Firstly, the circuit needs to be powered off, tested, and confirmed to be dead. Then, the multimeter gear switch should be set to the beep or resistance mode, and the two probes of the multimeter should be placed on Line 1 and Line 9 respectively
Under normal circumstances, press the SB1 or SB2 button separately, or manually press the springs of the two AC contactors separately (i.e. manually close the normally open point of KM1 or KM2). At this time, 1-9 will be conductive and the circuit will be open. The multimeter will have the corresponding coil resistance value.
If there is no resistance value, it indicates that the circuit is not connected. It is necessary to compare the circuit schematic and measure and analyze the continuity point by point. The measurement method is similar to voltage.
3, The resistance measurement method and voltage measurement method of a multimeter are the two most commonly used methods in circuit fault diagnosis. It can be said that each has its own advantages and convenience. The key is which method you habitually use, and use the multimeter to measure with the help of your most familiar method.
There are roughly two aspects regarding the range of circuit connectivity: first, the power supply part, and second, the electrical appliance part. To detect the power supply, adjust the measurement level of the multimeter to a higher level than the voltage level of the circuit being tested. For example, if your current power supply voltage is AC 220V, then if your multimeter is pointer type, the level should be set to AC 250V or AC 300V. If you are using a digital multimeter, you can set it to AC 750V. Then insert the black probe into the COM and the red probe into the V Ω socket. Although measuring AC voltage does not require high polarity, this is a requirement for using the instrument( https://www.dgzj.com/ Therefore, it is important to develop good work habits. If you are measuring for the first time, please pay attention to safety. Just like how we usually use chopsticks to eat, insert the two probes steadily into a power socket or the input or output terminals of a switch. At this time, the multimeter will display the current voltage. After measuring the voltage, if the power supply voltage is normal, the power supply part can be excluded. Otherwise, check the circuit between the socket and the distribution panel switch, including the power switch of this circuit. The next step is to measure whether the electric pancake pan is connected. First, disconnect the electric pancake from the power supply, adjust the multimeter to the resistance range of 200 Ω, and measure the power cord, power switch, temperature control switch, and heating element of the electric pancake separately. At this stage of measurement, except for the heating element of the electric pancake, the measurement result should be around 1 Ω. Otherwise, the problem in this part should be addressed.
