Electrical schematic design should meet the six aspects of the basic requirements

In general, the electric control schematic diagram should meet the requirements of machining process, circuit is safe and reliable, convenient operation and maintenance, less equipment investment etc, therefore, must correctly control circuit design, reasonably choose electrical components. Schematic design should meet the following requirements: 1, the principle of electrical control technology to meet the requirements in the design before production must be mechanical work performance, structural characteristics and the actual processing conditions are fully understand, and will consider on the basis of this control mode, starting, reverse, braking and speed requirements, set all kinds of interlock and protection device. 2, numerical control circuit power supply type and voltage requirements for the control circuit is simple, and there is not much electrical components, often directly use ac 380 v or 220 v power supply, power transformer without control. For more complex control circuit, control power transformer should be adopted, the control voltage to 110 v, 48 v or 24 v. This scheme for maintenance, reliable operation and electrical components of the work are good. For more frequent operation of dc electric drive control circuit, the commonly used 220 v or 110 v dc power supply. A direct current control circuit of magnet and electromagnetic clutch, often use 24 v dc power supply. Control circuit of ac voltage must be one or more of the following: the following provisions voltage 6 v, 24 v, 48 v, 110 v ( Preferred value) ，220V，380V，50Hz。 Control circuit of dc voltage must be one or more of the following provisions voltage: 6 v, 12 v, 24 v, 48 v, 110 v, 220 v. 3, ensure security and reliability of electrical control circuit in order to ensure the electrical control circuit, reliable work, should consider the following aspects: ( 1) Electrical components of the work to be stable and reliable, in line with the use of environmental conditions, and with the movement time does not cause competition. Complex control circuits, under the effect of a control signal, the circuit from one stable state to another steady state, they often have several electrical components of the state change at the same time, considering the electrical components there is always a certain time, for sequential circuits, you'll get a few different output state. This phenomenon is called the 'competition' of the circuit. For the switching circuit, due to the effect of release time delay of the electrical components, also can appear switch element is not the possibility of the logic function of the output by the requirement, this phenomenon is called 'adventure'. 'Competition' and 'adventure' phenomenon will cause control circuit can't action in accordance with the requirements, leading to control failure. Usually by analyzing the action of the control circuit of electric appliance and contact on and off, are static analyses, without considering the action time of the electrical components, and in actual operation, because of the electromagnetic coil electromagnetic inertia, mechanical inertia, mechanical displacement and other factors, make or relay contactor coil from electricity to contact closure, there was a time attract; Coil power, from the power of coil to off contact, there is a release time, these are called electrical components, action time, is inherent in electrical components, different from the set delay, inherent delay is uncontrollable, and man-made delay is adjustable. When the electrical components of the action time may affect the control circuit of the action, the need to use accurately reflect the element action time and cooperate with each other ( Such as timing diagram) To accurately analyze the action time, so as to guarantee the normal work of the circuit. ( 2) Electrical components of the coil and contact connection shall comply with the relevant state standard electrical components should comply with the regulations of the GB4728 graphic symbols, to arrange layout drawing. Main circuit, for example, are usually arranged in the left or above, the control circuit or auxiliary circuit is on the right or below, the component catalog tables arranged above the title. For the convenience of reading, and sometimes in the form of action status table or process diagram will command switch on and off, the electromagnetic valve action requirements, control flow shown in figure, can also be attached to the each side of the road in the control circuit control purpose. In the actual connection, the attention should be paid to the following: (1) the correct connection electric coil. Ac voltage coil usually cannot be used in series, even also can't use two same voltage coil in series, in the two times the rated voltage of the ac power coil, so as to avoid voltage uneven distribution of the work is not reliable. In direct current control circuit for inductance larger electric coil, such as solenoid valve, electromagnetic valve or dc motor excitation coil, etc. , should not be with the same voltage level or intermediate relay contactor used directly in parallel. When contact KM off, produce larger induced electromotive force on both ends of the electromagnet coil of YA, add on the coil of intermediate relay KA, KA caused by misoperation. Therefore in YA parallel discharge resistance R on both ends of the coil, and in series with KA branch KM normally open contacts, so you can reliable work. (2) the reasonable arrangement of electrical components and the location of the contact. For series circuits, electrical components or swap contact position, is not it works, but in actual operation, and the safety of the circuit and related to the wire length, (3) to prevent parasitic circuit. Parasitic circuit refers to the action process, in the control circuit of accident occurrence is not due to wrong operation processing circuit. (4) to reduce the number of wires as far as possible, shorten the length of the wires. (5) control circuit is working, should try to reduce the number of electric appliances, in order to reduce the possibility of failure and save power. 6 with small capacity in the circuit of relay contact to disconnect or connect large capacity contactor coil, to analysis the size of the contact capacity, if not enough, must increase or increase the intermediate relay relay capacity, otherwise the work is not reliable.