The motor on the crane has a rotor, and the rotor is controlled by a contactor, but the contactor do

There are a lot of such problems. There should be several levels of contactor cutting resistance, you see how many levels are not cut, if the first stage is not cut, you will check the first stage contactor coil, check the auxiliary point of the rising or descending contactor, check whether the common wire is broken, the cam controller contact closure, if it is the last few levels of contactor, take the first level without sucking you will check the auxiliary point of the previous contactor and the time relay. In short, the problem is very complex, and there are many places that are prone to problems.

You have to check it bit by bit according to the drawings. Hope it helps. If you have any questions, you can ask them in detail.

Learn together.

The rotor changes the speed by connecting the variable resistance value of the unbalance resistor, and generally runs at variable speed through the cam switch contact or contactor cutting resistance, and checks the cam contact or master switch, interlocking contact, contactor line, protection, etc.

1.There is no loop in the control line.

2.The end of the thread is loose and the contact is poor.

3.The power supply voltage is low.

4.The power supply is out of phase.

5.Contactor coil breaking.

6.The contactor magnet is stuck.

A relay is just a switch, just like the one you use in your home. It's just that it's controlled by electricity (whether the electromagnet is energized or not), and the switch in the home is controlled by hand. You are connected to AC, and the contact flow is AC; You're connected to DC, and the contact is flowing DC.

The main reasons for not engaging are the control end break, no call, poor grounding of the control end and control coil breakage.

Relay (also known as contactor) is a kind of electrical control device, which is an electrical appliance that makes a predetermined step change of the controlled quantity in the electrical output circuit when the change of the input quantity reaches the specified requirements. It has an interactive relationship between the control system (also known as the input loop) and the controlled system (also known as the output loop). Usually used in the control circuit of automation, it is actually a kind of "automatic switch" that uses a small current to control the operation of a large current.

For the above fault causes, they can be measured or tested by the voltage range, diode level and resistance file of the multimeter to determine which fault is it.

Check the main power supply voltage, whether there is a lack of phase, if the lack of phase check the incoming line, the current collector is usually called the slider, cart, trolley, whether the main order of the auxiliary hook is in the zero position, whether the emergency switch is closed, whether the limit of each bin door is in the closed position, whether the stop button is normal, whether the overcurrent is normal. These can be seen on the schematic. If the overcurrent, the bin door limit, the stop button is no problem, the main contact can be engaged with kicking, of course, the premise is that the contactor coil is normal, the control power supply is normal, and there is a situation that the trolley or cart limit is bad, and at this time, the zero contact of the trolley or cart is also broken, which can also cause the main power supply not to self-lock.

It's easier said than done, but it's still a bit of a hassle to actually check.