How to debug electrical equipment

- Aug 20, 2018-

1. On-site installation and wiring of electrical circuits

First of all, we need to know whether the site is a buried pipe or a bridge. According to the engineer's electrical circuit layout, find the end point of each equipment line on the site, and check whether the position of the buried pipe corresponds to the end point of each line of the equipment.

Second, the electrical cabinet is fixed on the site base, and multiple cabinets are to be connected to the cabinet. The busbar row is installed and the field console is also fixed.


Third, the primary circuit wiring is preferably the same cable specification.

This time, our electrician wiring, like to start all the lines from the head of the equipment, so that the multi-winding cable can be unpacked at the same time, and each time a position is changed, several coils of cables are moved together to move. Scattered. My suggestion is to take a roll of a certain specification cable, and then arrange all the cables from the head end to the end of the whole set to use the same specifications. For example, the same type of motor fan on the site, we can arrange these lines first. Ok, then check to make sure that there is no omission, then check the same set of specifications for the cable layout. Next, we proceed to the next set of cable routing of the same specification, and the layout is also checked in turn. In this way, only one cable of the specification is removed at a time, and after all the wiring of one cable is completed, the remaining cables of this specification can be put into the warehouse and the identification card can be attached for identification.


Fourth, to clarify the order of the wiring, the field wiring is preferably to first enlarge the line, then put the small line, first put the line once, then put the second line, first discharge the machine line, then put other load lines, each line is finished. It is necessary to do the signage. The advantage of first amplifying the line and then placing the small line is that in the cable trench or bridge, the large line does not press the small line. The advantage of first placing the line and then placing the second line is that the primary circuit can be completed as soon as possible with a relatively small number of lines, and the interference processing of the secondary line is facilitated.


I have written the wiring sequence of our Jiangsu site this time for everyone to refer to. The first thing we do is the motor wiring, and then start the wiring in turn: the wiring of the motor fan, the wiring of the heating resistor wire, the wiring of the button operating point in the control line, the hydraulic circuit, the wiring of the analog line such as the temperature sensor, the encoder circuit Wiring, wiring of communication lines. In this way, we solve the main loop first, and then solve the switching wiring of the control loop. We can find the wiring measures in the next vulnerable line, so that we can avoid the interference problem during the wiring phase. Micro-signal training is worth your attention.


 Fifth, regarding the wiring, first record which color or number corresponds to which terminal in each cable, and then complete one record, and the same specification is best. For example, all the motor wires are preferably unified into yellow, green and red. UVW. All cables and loads should be connected after the completion of one line, and then the secondary lines should be routed. The advantage of this is that it will not be confused, especially if there are many lines on the site. And it can make the scene look fresh, rather than being confused as if all the cables were left and the cables were exposed on the spot. Moreover, the wiring and wiring of one stage can make the installation project progress regularly in one stage and one stage, instead of grabbing the eyebrows and beards.


 Second, the electrical wiring debugging method


After the wiring is completed, we will perform line debugging to ensure that there are no errors.


First of all, we have to check whether the cable is connected incorrectly. Do not connect the cable of the A motor to the B motor. The cable of the A fan is connected to the B fan, especially the line that wears the same pipe. The control cable has the same cable. The color or number corresponding to each terminal on the terminal block of the electrical cabinet corresponds to the field operation point. For example, a button corresponds to a yellow line, but when it reaches the terminal of the electrical cabinet, it is connected with a green line. These should be checked carefully. Look at the motor phase between the short circuit, check whether there is a short circuit with the chassis, whether there is an open circuit, whether the button and indicator lines and terminal wiring match the circuit diagram, and so on.


 Secondly, the circuit should be debugged first. We should debug an electrical cabinet in an electrical cabinet. For example, the first electrical cabinet is all motor circuits. We can push the switch up and jog the contactor to see if the motor is reversed. If the reverse is changed immediately. Then try the second electrical cabinet, such as the fan circuit, and jog the contactor to see if the fan is reversed.


Third, debug all the buttons, now many control system buttons are connected to the PLC, we can press each button on the spot, another person in the PLC to observe the corresponding input indicator is not bright, if not, find out the reasons. Resolve the problem and make sure all button signals are OK and the button light is on.


 Fourth, debug all the feedback signals of the main circuit, such as all the motors in the first electrical cabinet. We can move the contactor one by one to check whether the signal is fed back to the PLC. If not, check the line. Observe whether the sampling signal is sampled, such as the ammeter connected to the current transformer. Use a screwdriver to hold the contactor to observe the current meter for current indication.


Fifth, manually run the inverter, DC governor, check the motor for any problems, the gearbox has no abnormal noise, and the motor encoder has no feedback. For example, this time we are debugging the 590 DC governor. We made a simple small button box. One of the two selector switches is used to start one for enabling. A potentiometer is used to give a 0-10V signal. We connect the button box to the governor and then we can The motor is commissioned and the encoder feedback signal can be seen on the 590. For example, when a DC motor is tested, we will report an error immediately. This is because the direction of the encoder feedback is opposite to the actual direction of the motor, and the direction of the motor is correct. So we reverse the A and B signals of the encoder. It is.


 Sixth, check if the signal source of all other feedback signals can feedback the signal to the PLC normally. For example, for an electrical appliance, we use the transformer to sample the current signal to trigger the intermediate relay, and use the normally open signal of the intermediate relay to feed back to the PLC. We can use the screw to press the contactor of this appliance to energize, observe whether the corresponding input indicator of the PLC is on, and ensure that there is no problem with the feedback signal. For example, if a position sensor on the site feeds back different resistance values as the position moves, we can move the position to let one person measure whether the resistance value of the other end of the electrical cabinet line changes normally to ensure normal feedback of the resistance signal and eliminate the line. The feedback caused by the problem is wrong.


 At this point, we can basically eliminate the line problems one by one, you can proceed to the next PLC program debugging, the whole set of equipment linkage debugging.


 Summarize the above content, the actual is to install the line first, then put the line once, put a specification cable to complete the copper nose to connect the line in one stage and one stage; check the line safety first, then debug The direction of the motor ensures that the manual operation is normal and the signal is fed back to the PLC or other controller. Step by step, clear thinking, find problems and solve problems, improve your ability to work.


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