Multimeter measures the quality of electromagnets
Generally, a multimeter is used to measure the DC resistance value. Small high-voltage coils are generally several hundred thousand or a few megaohms at most. The accuracy requirements are not high. The actual measured value is compared with the design value or other equivalent coils without faults. Low-voltage coils are generally at the milliohm level, and the precise resistance cannot be measured with a multimeter (the error is large). A special direct resistance tester must be used.
However, in actual measurement, it cannot be said that the actual measured value is the same or almost the same as the designed value to conclude that the coil is good. Sometimes the insulation between coil turns or layers is damaged, which cannot be measured with a multimeter.
You can use the resistance measurement instead. First use a normal electromagnet coil to measure the resistance, and then measure the problematic electromagnet coil. If the resistance value is too different, it means that the electromagnet is not normal.
Analysis of the problems of measuring the quality of electromagnets:
Problems with electromagnets: Sometimes the suction force is not enough to suck it in, sometimes the suction force is too strong and the ejection is too slow, sometimes it sucks and sometimes it doesn't. How to measure the electromagnet?
You can use a multimeter to measure the electromagnet, and use a multimeter to check the on-off resistance of the coil to judge the quality of the electromagnet.
The parameters of the coil are basically unchanged, and the suction force is determined by the voltage, the spring force, and the initial position of the iron core.
Focus on checking whether the voltage fluctuates and whether the spring force is within the allowable range.
The initial position of the iron core refers to the distance between the iron core and the retaining iron at the bottom of the coil before the electromagnet coil is energized. If this distance is too large, it will not be able to attract the electromagnet.
Regarding the problem that sometimes the suction force is too high and the ejection is too slow, excessive suction force only affects the speed at which the iron core is sucked in, and has nothing to do with whether it can be ejected. When the iron core pops up, the coil is de-energized, and the speed of the pop-up is determined by the spring force.
It can be seen that the problem is not with the coil, and the problem does not need to be measured with a multimeter.
The above is how to use a multimeter to measure the quality of electromagnets. I hope it will be helpful to everyone.
