Reasons why the AC contactor does not pick up

The contactor does not pick up most of the contactor itself does not get the supply voltage, and the coil breakage or armature jam is extremely rare. When judging, use the multimeter to measure the working voltage of the contactor coil. If there is no voltage, continue to find the relevant circuit of the coil power supply. For example: coil power supply, button, interlock button related to coil power supply, auxiliary normally open, normally closed contact of interlocking contactor, thermal relay contact, timer contact, etc. are connected in series with the contactor coil Whether the control contact function is normal, and finally find the fault point that the coil cannot supply power. (Of course, if the coil has a voltage that does not pick up, it can be replaced directly)

AC contactor is a commonly used circuit control appliance and has certain applications in many fields. In the process of using the AC contactor, there is a problem of improperly engaging, which means that the AC contactor is too slow to pull, the contact cannot be completely closed, and the iron core emits abnormal noise and the like. So what are the causes and treatments that are not normal? Let's take a look at the following small series.

1. Since the power supply voltage of the control circuit is lower than 85% of the rated voltage, the electromagnetic force generated after the electromagnetic coil is energized is small, and the movable iron core cannot be quickly sucked toward the static iron core, causing the contactor to suck slowly or the suction is not tight. The power supply voltage of the control loop should be adjusted to the rated operating voltage.

2. The spring pressure is insufficient, causing the contactor to be improperly sucked; the reaction force of the spring is too large, causing the suction to be slow; the contact spring pressure overshoot is too large, so that the iron core cannot be completely closed; the spring pressure and release pressure of the contact Too large, causing the contacts to not close completely. The solution is to properly adjust the spring pressure and replace the spring if necessary.

3. Because the gap between the moving and static iron core is too large, the movable part is stuck, the rotating shaft is rusted or deformed, and the contactor is not properly sucked. During the treatment, the moving iron core can be removed for inspection, the gap is adjusted, the shaft and the support rod are cleaned, and the fittings are replaced if necessary.

4. Due to long-term frequent collisions, the iron core surface is not flat and expands outward along the thickness of the laminated sheet. At this time, the boring tool can be used for trimming and the iron core can be replaced if necessary.

5. The short-circuit ring breaks, causing the core to make an abnormal sound. In this case, replace the short-circuit ring of the same size.