How to measure the quality of electromagnet with multimeter
The electronic iron on our machine always has electromagnet problems. Sometimes the suction is not enough to suck it in, and sometimes the suction is too strong and the ejection is too slow. Sometimes it sucks and sometimes it doesn't, how to measure an electromagnet?
Use a multimeter to measure the electromagnet, and also check the on-off resistance of the coil. From the situation described by the subject, the problem should not be on the coil.
The parameters of the coil are basically unchanged, so the suction force is determined by the voltage, the spring force, and the initial position of the iron core. So check for voltage fluctuations? Is the spring force within the allowable range? The initial position of the iron core refers to the distance between the iron core and the iron stop at the bottom of the coil before the electromagnet coil is powered on. If this distance is too large, it will not be able to attract. Sometimes the suction force is too large 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. The coil is de-energized when the iron core is ejected, and the ejection speed is determined by the spring force.
Precautions when choosing resistance substitution in multimeter
Whether it is a pointer multimeter or a digital multimeter, there are many resistance-capacitance components inside it, especially resistors, which play an important role in voltage division and current shunting in the multimeter. If the resistor is damaged, you can use a replacement with the same resistance value, and it doesn't matter if the power is higher.
Although the resistor can be replaced with a resistor of the same resistance value after the resistor is damaged, the resistor in the multimeter is special. In order to form the proportional relationship of each range, the resistor inside is generally a resistor value that is not commonly used, such as 0.99 ohms. Since resistors with special resistance values are not commonly used and are not easy to buy, if you use a resistor close to the resistance value instead, such as using 1 ohm, the measurement accuracy will change. Even if the resistance value of some resistors belongs to the conventional resistance value, the accuracy of the main resistor should be selected when choosing a resistor replacement.
