The electrical control circuit of the machine tool is different from the type, function and processing technology of the machine tool. In addition to electrical control for various cutting movements and auxiliary movements, there are many electrical control contents such as lighting and cooling, and the electrical control circuit is more complicated. The drawings that are drawn from the electrical graphic characters and symbols specified in the national standard are used to express the electrical control system's principles, functions, uses, and the arrangement, connection, and installation relationship between electrical components. There are electrical schematics, electrical wiring diagrams and electrical installation drawings. Figure 1 is the electrical schematic of the CW6132 lathe. The diagram includes the connection between all the electrical components of the machine and the connection points. Fig.1 Electrical schematic of the CW6132 lathe 1) illustrates a state of the electrical contact element of the appliance should be non-energized state and the unstressed state the contact state shown in FIG <br> electrical plotted. 2) Text labeling rules <br> Text labeling in electrical drawings follows the nearest labeling rules and the same rules. The so-called nearest rule is that the electrical symbols of the electrical components of each electrical component should be marked in the vicinity of the graphical symbol; the same rule means that different conductive components of the same electrical component must use the same textual symbol (as in Figure 1, the AC contactor coil The main contact and its auxiliary contacts are all marked with the same text (KM). 1) Connection layout Vertical arrangement of electrical components and equipment <br> graphic symbols arranged in the longitudinal direction from left to right, the connecting lines are arranged vertically, laterally aligned similar items, typically tools are electrical schematics method using this arrangement. <br> horizontal arrangement of electrical components and equipment graphic symbols arranged laterally from the top down, the connection is arranged horizontally, longitudinally aligned similar items. 2) off <br> cross at an intersection node of the node drawn connecting black circles represent two intersecting at the node is turned on, no electric contact no black circle; T-byte node point was turned on, see figure 2. 3) Line number and specification Figure 2 Intersection of Crossover Nodes The line numbers are marked with L1, L2, L3, U, V, W, etc. The connection specifications are marked with lead lines according to the principle of proximity. For example, the lead lines are used in Figure 1 to mark the ends of the lead lines in the main circuit area of ​​the cooling motor. The marked 2.5mm2 indicates that the sectional area of ​​the connection is 2.5mm2. Excessive labeling of connection specifications can lead to confusion of drawings and can be highlighted in the electrical component schedule. 4) Annotation of the node's digital symbol <br> For the convenience of annotation, the circuit symbol can also be marked at the node of the electrical schematic diagram, as shown in the lighting circuit area 4, 5, 6, 7 and 8 in Fig. 1. Digital symbols are generally arranged in the flow direction of the current in the branch. In addition to the annotation function, the role of the node digital symbol also serves to match the electrical schematic with the electrical wiring diagram. In order to determine the location of the content on the map and its use, some electrical diagrams with large dimensions and complex content should be partitioned. 1) Vertical partitioning method and arrangement are denoted <br> electrical schematic, the upper control link and the functional press generally main circuit partition text from left to right, and adding notes to each partition in the box, the machine help reading of electrical schematic; generally downward press "branch centering" principle numerals have partition from left to right, and filling in each partition block numbers for easy access electrical contact position relays, contactors and the like. The principle of “bridging the roads centrally†means that the vertical line of each branch should be aligned with the midline of the digital zone box. For the horizontal layout of the electrical schematic, left and right partitions are implemented. The text description area is divided from the top down on the left and the digital labeling partition is on the right top down. 2) Contact Index Codes <br> AC contactors and relays in the electrical schematic diagram, because the role of the coil, the main contact, and the auxiliary contact are all different, in order to clearly show the working principle of the machine electrical schematics, these components Usually drawn in the branches that each function. In the large-scale complex electrical schematic diagram, for the convenience of retrieval, it is necessary to mark the contact index number of the electromagnetic coil under the electromagnetic coil graphic symbol, as shown in FIG. 3 . Figure 3 The contact index of the electromagnetic coil For the contactor contact index code is divided into left and right three columns, the left column number indicates the number of the main contact where the partition number, the middle column of the number indicates that the normally open auxiliary contact where the digital partition number, the right column indicates the normally closed auxiliary The number of the partition where the contact is located. The electrical diagrams that represent detailed information on the connections between the various items (including electrical components, components, and equipment, etc.) of the electrical control system, wiring types, and routings are called electrical wiring diagrams, and the electrical wiring diagrams are not for inspection circuits and maintenance circuits. The missing technical documents can be subdivided into unit wiring diagrams, interconnection wiring diagrams, and terminal wiring diagrams, depending on the object of expression and purpose. Figure 4 Electrical interconnection diagram of CW6132 lathe The electrical components inside the electrical control cabinet can be directly connected, and the connection between the external components and the electrical cabinet must be carried out through the terminal board. The connection conductors should indicate the number of conductors, the cross-sectional area of ​​the conductors, etc., and generally do not indicate the actual routing of the conductors. During the construction, the operator chooses the best route according to the actual situation. Figure 5 is the electrical control schematic for the C650 horizontal lathe. The lathe total of three motors: M1 is a spindle motor, spindle rotation and dragging realize feed movement by the feed mechanism, there are forward and reverse control, rapid stop parking brake, the movable point adjustment operation processing Electrical control requirements. M2 is the cooling pump motor, which drives the cooling pump motor to supply fluid to the parts to be machined. The electrical control requirement is to start the fluid supply during processing and to operate for a long period of time. The M3 is a fast moving motor. The tool holder is quickly moved and requires manual control of starting and stopping at any time. Fig. 5 Electric control circuit of C650 horizontal lathe 1) Main motor circuit Power supply introduction and fault protection <br> After the three-phase AC power supply L1, L2, L3 is fuse FU, QS isolation switch is introduced into the main circuit of C650 lathe. In the main motor circuit, FU1 fuse is a short circuit protection link, FR1 is a thermal relay The heating element acts as an overload protection for the motor M1. The main motor reversal KM1 and KM2 are the main contacts of the AC contactors KM1 and KM2, respectively. The analysis shows the basics of the electrical control, the main contact is closed KM1, KM2 when the main contacts are open, respectively connected to three-phase AC power U1, V1, W1 in the three-phase windings of the motor, the main motor Ml forward. Conversely, when the KM1 main contact is opened and the KM2 main contact is closed, the three-phase AC power supply will be connected to the W1, V1, and U1 three-phase windings of the M1 main motor, respectively, compared with the forward rotation, U1 and W1. The changeover leads to a reverse of the main motor. Main motor with full voltage when the reduced pressure state <br> KM3 main contacts are open, three-phase AC power source current will flow through the current limiting resistor R into the motor winding, the motor winding voltage will decrease. If the KM3 main contact is closed, the power supply current is directly connected to the motor winding without a current limiting resistor, and the main motor is in full-voltage operation. Winding current monitoring The ammeter A plays the role of monitoring the winding current in the main circuit of the motor M1. The TA coil is placed on the wiring of one phase of the winding. When a current flows through the wiring, an inductive current will be generated. Through this inductive current, the motor winding is displayed. Current current value. The control principle is that when the KT normally closed delay open contact is closed, the induced current generated by the TA does not pass through the A current meter, but once the KT contact is opened, the A current meter can detect the current in the motor winding. The motor speed monitoring KS is a speed relay detection element installed along with the M1 main motor spindle, and controls the closing and opening of the speed relay contacts according to the spindle speed of the main motor. 2) the motor circuit <br> cooling circuit pumps coolant pump motor in a short-circuit protective fuse FU4, FR2 thermal overload relay will play a role. When the KM4 main contact is disconnected, the cooling pump motor M2 is stopped without supplying liquid; and when the KM4 main contact is closed, M2 will start the supply of liquid. 3) Rapid traverse motor circuit in the motor circuit <br> rapid traverse FU5 short circuit protective fuse. When the KM5 main contact is closed, the quick-moving motor M3 starts, and the KM5 main contact opens, and the quick-moving motor M3 stops. The general method of control circuit read graph analysis is to start with the relationship between the disconnection and closing of various types of contacts and the corresponding power loss of the electromagnetic coil, and through the state of power off of the coil, analyze the main touch controlled by the coil in the main circuit. The disconnected state of the head leads to the conclusion that the motor is in a controlled operating state. 　　 1) to move the main motor control <br> press SB2, KM1 coil is energized, the normally-off leg based on the original state phenomena, all of the remaining coils are de-energized. Therefore, in the main circuit, the KM1 main contact is closed. The three-phase AC power introduced by the QS isolation switch will be connected to the three-phase winding of the main motor M1 via the KM1 main contact and the current limiting resistor. The main motor M1 series resistance decompression starts. . Once the SB2 is released, the KM1 coil is de-energized and the motor M1 is de-energized and stopped. SB2 is a jog control button of the main motor M2. 2) main motor normal rotation control <br> press SB3, KM3 coil is energized with KT windings are energized simultaneously, and through the normally open auxiliary contact region 20 KM3 the closing coil energized KA, KA turn causes energization of the coil 11 in the region The KA normally open auxiliary contact closes, energizing the KM1 coil. On the other hand, the KM1 normally open auxiliary contact in the 11 to 12 zone and the KA normal open auxiliary contact in the 14 zone form the self-locking on the SB3. In the main circuit, the KM3 main contact and the KM1 main contact are closed. The motor does not pass the current limiting resistor R and the full-voltage forward rotation starts. 3) Press the main motor <br> SB4, inversion control, through the lead line 9,10,5,6 KM3 coil and KT coil is energized, the normal rotation control similar, KA energization of the coil region 20, 11, 12 and through , 13, 14 Power on the KM2 coil. In the main circuit, the main contacts of KM2 and KM3 are closed, and the motor is fully reversed and started. The branch of the KM1 coil and the branch of the KM2 coil pass through the normally closed contacts of KM2 and KM1 to achieve the electrical control interlock. 4) Main motor reverse brake control Forward brake control Reverse brake control 5) cooling the pump motor to stop the control <br> press SB6, KM4 coil is energized, and through normally open auxiliary contact KM4 SB6 for self-locking, the main circuit KM4 main contacts are closed, coolant pump motor M2 is rotated and held. Press SB5, KM4 coil power off, cooling pump motor M2 stall. 6) Rapid traverse motor to move the control handle holder <br> travel switch controlled by a lathe. Turn the knife holder handle and the limit switch SQ will be depressed and closed, and the KM5 coil will be energized. In the main circuit, the KM5 main contact is closed, and the motor M3 that drives the tool carriage to move quickly starts. The counter-rotating tool holder handle is reset, and the SQ travel switch is opened, then the motor M3 stops and stops. 7) the lighting circuit <br> lamp switch SA is placed in a closed position, EL lights. When the SA is in the off position, the EL lamp is off. The symbols and names of electrical components in the electrical schematics of the C650 horizontal lathe are given in the table below. Table C650 Lathe Electrical Component Symbols and Names symbol name symbol name M1 Main motor SB1 Stop button M2 Cooling pump motor SB2 Main motor forward jog button M3 Fast moving motor SB3 Main motor forward button KM1 Main motor forward contactor SB4 Main motor reverse button KM2 Main motor reversal contactor SB5 Cooling pump motor stop button KM3 Short-circuit current limiting resistor contactor SB6 Cooling pump motor start button KM4 Cooling pump motor start contactor TC Control transformer KM5 Quick-moving motor start contactor FU(1~6) Fuse KA Intermediate relay FR1 Main motor overload protection thermal relay KT Power on delay time relay FR2 Cooling pump motor protection thermal relay SQ Fast moving motor jog switch R Current limiting resistor SA switch EL flashlight KS Speed ​​relay TA Current Transformer A Ammeter QS Isolation switch Three tasks Describe the control principle of the electrical control circuit of the ordinary lathe; survey the electrical control circuit of the ordinary lathe through surveying and mapping. Customized Seamless Steel Tube Shandong Yuzhong Steel Co., Ltd. , https://www.cnyzsteel.com
Electrical drawings must comply with the latest electrical drawing standards issued by the National Bureau of Standards. At present, there are mainly GB/GT4728-1996~2000 "graphical symbols for electrical diagrams", GB7159-1987 "General Rules for the Development of Text Symbols in Electrical Technology," and GB4026-1992 "Identification and Application Letters for Electrical Equipment Terminal Blocks and Specific Wire Ends." General Principles of Digital Systems, GB/T6988.3-1997 Electrical Drawings, Wiring Diagrams, and Wiring Diagrams, GB/T6988.1-2002, Preparation of Electrical Technical Documents, etc. In addition, the relevant standards for mechanical drawings and architectural drawings must also be observed. 
For the contactor, the electromagnetic relay contact is drawn according to the status when the electromagnetic coil is not energized; for the button, the position switch is not drawn when the external force acts; for the low voltage circuit breaker and the combination switch is drawn according to the disconnected state; the thermal relay is pressed off Buckle state drawing; speed relay drawing according to the state when the motor rotation speed is zero; accident, backup and alarm switch, etc. are drawn according to the state when the device is in normal operation; manual switches marked with “OFF†and other stable operation positions are dialed. The state is drawn in the "OFF" position.
The text itself should comply with the provisions of GB4457.3-84 "Mechanical Drawing Documents." Using italics characters long, there is a high 20,14,10,7,5,3.5,2.5 other seven word, font width approximately equal to 2/3 of the high words, letters and numbers, and a stroke width of about high word / 10 and so on.
The wiring layout adopted when drawing the electrical schematic diagram should be consistent with the actual connection layout in the electrical control cabinet. 
a) There is a black dot cross node b) There is no black dot cross node c) T byte point 
a) Contactor contact index code b) Relay contact index code
For the relay contact index code is divided into two columns, the left column indicates the number of the normally open contact where the partition number, the right column indicates the number of the normally closed contact where the partition number.
Figure 4 is the CW6132 lathe electrical interconnect wiring diagram. In the wiring diagram, the figures and characters of each electrical component are consistent with the electrical schematic of the CW6132 lathe, but the position of each electrical component is drawn according to the actual position of the electrical component in the control cabinet, control panel, console or control box. The dashed box on the left in the figure indicates the electrical control cabinet of the CW6132 lathe, the middle small box indicates the lighting control board, and the right small box indicates the machine movement control board. 
The main circuit establishes electrical contact with the control circuit and the lamp circuit via the TC transformer. Access TC transformer primary side voltage 380V, the secondary side 36V, 110V two power supply, wherein a lighting circuit power supply 36V, and 110V to the lathe control line supply.
The control line is from zone 6 to zone 17. The branches are arranged vertically and they are connected in parallel. The coils and contacts are all in the original state (ie, they are not in the force state or the non-energized state), while the branches in the original state are all in the open state, so the coils of KM1, KM3, KT, KM2, KA, KM4, KM5, etc. In the power-off state, this phenomenon can be referred to as the "original branch normally-off", which is an important technique for the machine-control line reading diagram analysis.
In the winding current monitoring circuit, the delay begins after the KT coil is energized, but since the delay time has not yet been reached, the normally closed KT contact is closed and the induced current is short-circuited by the KT contact, resulting in no A current meter. The passage of current avoids excessive winding current at the beginning of full-voltage start-up and damages the A current meter. When the delay time of the KT coil is reached, the motor has approached the rated speed, and the KT in the winding current monitoring circuit will be disconnected. The induced current flows into the A current meter and the current value in the winding is displayed on the A table.
KS2 is the forward rotation control contact of the speed relay. When the motor rotates forward to near the rated speed, KS2 is closed and maintained. When SB1 is pressed during braking, all the electromagnetic coils in the control circuit will be powered off. The main contacts of the KM1, KM2, and KM3 are all disconnected in the main circuit. The motor is decelerated and decelerated, but due to the forward rotation inertia, it takes longer. Time can be reduced to zero speed.
Once SB1 is released, the KM2 coil is energized via 1, 7, 8, KS2, 13, and 14. In the main circuit, the KM2 main contact is closed. The three-phase power supply current is switched to two phases U1 and W1 through KM2, and then the current limiting resistor R is inserted into the three-phase winding to form a reverse torque on the motor rotor. The inertial torque of the rotation cancels and the motor stops quickly.
The KS1 reversing control contact will not generate a closing action and remain in a normally open state during the forward rotation of the motor to the rated rotation speed and then from the rated rotation speed to the stop.
The KS1 closes and holds when the motor is reversed to near normal speed. Similar to forward braking, press SB1 and the motor decelerates. Upon release SB1, then after 1,7,8, KS1,2,3, KM1 energizing the coil, is formed on the forward torque motor rotor, and the inverted offset the inertia torque rapidly stop the motor.
Ordinary lathe electric control circuit read investigation