Some electric friends shared that I am a factory electrical maintenance worker, often use a multimeter to measure the electrical control circuit of the motor, need to use a multimeter to measure the quality of the motor in the case of power failure, often misjudged, because the digital multimeter number is always flashing, even if the contact is good, it is not stable!
If the amount is different after a period of time, what good way can you overcome? I use a digital multimeter! I want to change a pointer meter, pocket-sized and easy to carry, it is best to combine a megohmmeter multimeter into a small and easy to carry, know the great god friends to support a trick, thank you here.
Electric friend A: The structure and principle of the pointer multimeter and the digital multimeter are not the same, and there are differences in performance, when conditions permit, it is recommended that both kinds of multimeters are purchased and used, the input impedance of the digital multimeter is very high, and the digital multimeter should be the first choice for measurement occasions with high accuracy requirements. A digital multimeter should be used to measure the resistance of small resistance and high accuracy requirements, and to measure the capacitance of capacitors.
However, the response time of a digital multimeter is slower than that of an analogue type. Compared with analog multimeters, it is more susceptible to external interference. A digital multimeter, which tests some continuously changing amounts of electricity and processes, is not as convenient and intuitive as an analog multimeter. The shunt effect of the pointer multimeter has a great impact on the circuit under test, and the measurement accuracy is low, and the measurement gear needs to be changed frequently in use. But the measurement results are quick and intuitive.
Friend B: Direct digital multimeter, the kind that requires a 9V battery, and a FLUKE one. It is best to test the temperature, frequency, with a low impedance voltage test gear, you can test 1000V DC 750V AC, and then with an AC and DC clamp current meter, all of which must be true RMS, if the interference is very large, the solution is also a lot, you can put the resistance of the low resistance value and capacitance at the meter head or something to test the resistance value of your motor coil, which also has a certain effect. Preferably, of course, with an LCR bridge. Don't spray me if it's not right, I'm not a professional and am not responsible for the above statement.
Electrician C: Measuring the winding resistance of a motor in a complex electromagnetic environment is not true. Because at this time, the coil will produce a weak voltage to interfere with the measurement results, just like the multimeter measures the resistance of the dry battery, and the multimeter resistance is often said to measure the 220 voltage.
The only solution is to move the motor to a place where there is no interference, and then measure it, or put a shield on it. There is no problem with measuring the winding resistance with a multimeter and the difference is not obvious, and the multimeter does not use a pointer pen when measuring, but a crocodile clip. Personally, I think that the pointer multimeter is good, the digital meter is not, the general mechanical and electrical maintenance needs to be very accurate in two places, one is 0~20mA current measurement, the other is 0~10V analog, other voltages and currents are approximate values, as long as the deviation is not too outrageous can be accepted.
Do you have any other opinions on the old electricians? Welcome to discuss in the comment area! [Think]
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