How to judge the quality of AC contactor on the machine - Database & Sql Blog Articles

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1. Look: A, see if it works. B. Start up if the contactor pulls in. At this time, the fan works, the press does not work (the capacitor is good), and the contactor can be preliminarily determined to be bad. Since the press and the external fan are controlled by the normally open contacts of the contactor, the contact work is synchronized. If one of the jobs is not working, the other one can be roughly judged as a smooth contact.
2, Listen: A, listen to whether it has a very loud bang - the sound, if any, may be (1) low power supply voltage; (2) there is dirt on the contact point or there is dirt on the contact surface of the moving iron core. If you hear the sound that the 接触-contactor can't suck, there are two cases (1) the power supply voltage is low; (2) the contact sip suction is not enough.
3, smell: smell there is no burnt smell, if you have to check the windings and contacts.
4. Quantity: Power off the line at the end of the contact control, use the multimeter to measure the volume, press the three main contacts of the test end and the other set of normally open contacts, all should be conductive, often The closed contact should not be turned on. When the test tip is lowered, neither the main contact nor the normally open contact should guide the normally closed contact to be conductive. The coil winding value is about 200 。. Before the measurement, the wire at one end should be removed and measured.
5. Short-circuit: After starting, after the contactor is closed, if the press does not turn, you don't know if the contact of the contactor is broken. You can use the needle-nosed pliers* to open, and use the two pointed ends to short the same group. Contact, when the press is working, it proves that the contact is broken (Note: Pay attention to safety when using this method)