Classification of electrical instruments
First, according to the working principle: electromagnetic, magnetoelectric, electric, inductive, rectifying, thermoelectric, electrostatic, electronic and so on.
Second, according to the nature of the measurement: there are ammeter, voltmeter, power meter, ohmmeter, electricity meter, power factor meter, frequency meter, multimeter and so on.
Third, according to the way of use: switch board and portable.
Switch panel meters are usually fixed on the switch board or switchboard with large errors. Portable meters generally have small errors and high accuracy.
Fourth, according to the working current points: there are DC instruments, AC instruments, AC and DC meters.
Composition of electrical instruments
Commonly used electrical instruments are mainly made of bakelite or iron or hard plastic, panels with scales and symbols, measuring lines (simple meters), head electromagnetic systems, pointers, dampers, shafts, bearings, springs , zero adjuster and other components.
Electrical instrument requirements
In order to ensure the accuracy and reliability of the measurement results, the following requirements are imposed on the electrical instrument:
1. High accuracy and small error, the value should meet the requirements of the accuracy;
2. The error should not change with the influence of external environmental conditions such as time, temperature, humidity, and external magnetic field;
3. The power consumption of the meter itself should be as small as possible. Otherwise, when measuring small power, it will cause a large error;
4. The meter should have sufficient insulation strength and pressure resistance, and should also have the ability to withstand short-term overload to ensure safe use;
5, should have a good reading device, the measured value should be able to read directly;
6, the structure is sturdy, easy to use and maintain.
Glyph of electrician instrument
The dial of the electrician is marked with various symbols to indicate the type of the instrument, the object to be measured, the measurement range, the accuracy, and the conditions of use.
The accuracy level of electrical instruments is divided into seven levels of 0.1, 0.2, 0.5, 1.0, 1.5, 2.5, and 5.0. The smaller the number, the higher the accuracy.
According to the ability to resist external magnetic field or electric field interference, it is divided into I, II, III, IV, etc., among which I has the best defense ability.
According to the conditions of use, it is divided into three groups: A, B, and C. Groups A and B are used indoors, and group C is used for outdoor or ship, aircraft, and vehicle.
Maintenance of electrical instruments
1. Strictly follow the instructions, save and use in the temperature, humidity, dust, vibration, electromagnetic field and other conditions.
2. After long-term storage, the meter should be energized regularly to check and remove moisture.
3. After long-term use of the instrument, the necessary inspection and correction shall be carried out according to the electrical measurement requirements.
4. Do not disassemble and debug the instrument at will, otherwise it will affect its sensitivity and accuracy.
5. For the instrument with battery in the table, pay attention to check the discharge condition of the battery. If it is not user, it should be replaced in time to avoid the battery electrolyte overflowing and corroding the machine. For instruments that are not used for a long time, the battery inside the watch should be taken out.
Correct use of electrical meters
How to properly use and rationally select electrical measuring instruments:
1. Select the instrument type according to the nature of the measurement object. First of all, depending on whether DC or AC is being measured, DC instruments or AC instruments can be selected. If you measure the amount of AC, you should also pay attention to whether it is a sine wave or a non-sinusoidal wave; when measuring, it is necessary to distinguish whether the measured value is the average value, the effective value, the instantaneous value, or the maximum value, and pay attention to the frequency for the AC quantity.
2. Select the instrument level according to the actual needs of the measurement object. According to the nature of the project, as long as the error of the measurement results is within the practical allowable range of the project. For example, in commonly used standards and some precision measurements, instruments with an accuracy of 0.1 to 0.2 can be used; in the experimental measurement, instruments of 0.5 to 1.5 can be used; in the factory production, instruments of 1.0 to 5.0 can be used.
3. Select the internal resistance of the meter according to the resistance of the measuring object and the measuring line. For the voltmeter that measures the voltage, the larger the internal resistance is, the better the resistance inside the voltmeter is greater than 100 times the measured object. For an ammeter that measures current, the smaller the internal resistance, the better. It is often required that the internal resistance of the ammeter is less than 100 times that of the object under test.
4. Select the allowable rating of the meter according to the measurement object. Do not use a large range of meters to measure small values ​​to avoid readings. Of course, it is even more difficult to measure the large amount of power with a small-range meter to avoid damage to the meter. Therefore, when selecting the instrument, you must carefully observe the rated voltage, rated current and rated power that the instrument and equipment are allowed to withstand.
First, according to the working principle: electromagnetic, magnetoelectric, electric, inductive, rectifying, thermoelectric, electrostatic, electronic and so on.
Second, according to the nature of the measurement: there are ammeter, voltmeter, power meter, ohmmeter, electricity meter, power factor meter, frequency meter, multimeter and so on.
Third, according to the way of use: switch board and portable.
Switch panel meters are usually fixed on the switch board or switchboard with large errors. Portable meters generally have small errors and high accuracy.
Fourth, according to the working current points: there are DC instruments, AC instruments, AC and DC meters.
Composition of electrical instruments
Commonly used electrical instruments are mainly made of bakelite or iron or hard plastic, panels with scales and symbols, measuring lines (simple meters), head electromagnetic systems, pointers, dampers, shafts, bearings, springs , zero adjuster and other components.
Electrical instrument requirements
In order to ensure the accuracy and reliability of the measurement results, the following requirements are imposed on the electrical instrument:
1. High accuracy and small error, the value should meet the requirements of the accuracy;
2. The error should not change with the influence of external environmental conditions such as time, temperature, humidity, and external magnetic field;
3. The power consumption of the meter itself should be as small as possible. Otherwise, when measuring small power, it will cause a large error;
4. The meter should have sufficient insulation strength and pressure resistance, and should also have the ability to withstand short-term overload to ensure safe use;
5, should have a good reading device, the measured value should be able to read directly;
6, the structure is sturdy, easy to use and maintain.
Glyph of electrician instrument
The dial of the electrician is marked with various symbols to indicate the type of the instrument, the object to be measured, the measurement range, the accuracy, and the conditions of use.
The accuracy level of electrical instruments is divided into seven levels of 0.1, 0.2, 0.5, 1.0, 1.5, 2.5, and 5.0. The smaller the number, the higher the accuracy.
According to the ability to resist external magnetic field or electric field interference, it is divided into I, II, III, IV, etc., among which I has the best defense ability.
According to the conditions of use, it is divided into three groups: A, B, and C. Groups A and B are used indoors, and group C is used for outdoor or ship, aircraft, and vehicle.
Maintenance of electrical instruments
1. Strictly follow the instructions, save and use in the temperature, humidity, dust, vibration, electromagnetic field and other conditions.
2. After long-term storage, the meter should be energized regularly to check and remove moisture.
3. After long-term use of the instrument, the necessary inspection and correction shall be carried out according to the electrical measurement requirements.
4. Do not disassemble and debug the instrument at will, otherwise it will affect its sensitivity and accuracy.
5. For the instrument with battery in the table, pay attention to check the discharge condition of the battery. If it is not user, it should be replaced in time to avoid the battery electrolyte overflowing and corroding the machine. For instruments that are not used for a long time, the battery inside the watch should be taken out.
Correct use of electrical meters
How to properly use and rationally select electrical measuring instruments:
1. Select the instrument type according to the nature of the measurement object. First of all, depending on whether DC or AC is being measured, DC instruments or AC instruments can be selected. If you measure the amount of AC, you should also pay attention to whether it is a sine wave or a non-sinusoidal wave; when measuring, it is necessary to distinguish whether the measured value is the average value, the effective value, the instantaneous value, or the maximum value, and pay attention to the frequency for the AC quantity.
2. Select the instrument level according to the actual needs of the measurement object. According to the nature of the project, as long as the error of the measurement results is within the practical allowable range of the project. For example, in commonly used standards and some precision measurements, instruments with an accuracy of 0.1 to 0.2 can be used; in the experimental measurement, instruments of 0.5 to 1.5 can be used; in the factory production, instruments of 1.0 to 5.0 can be used.
3. Select the internal resistance of the meter according to the resistance of the measuring object and the measuring line. For the voltmeter that measures the voltage, the larger the internal resistance is, the better the resistance inside the voltmeter is greater than 100 times the measured object. For an ammeter that measures current, the smaller the internal resistance, the better. It is often required that the internal resistance of the ammeter is less than 100 times that of the object under test.
4. Select the allowable rating of the meter according to the measurement object. Do not use a large range of meters to measure small values ​​to avoid readings. Of course, it is even more difficult to measure the large amount of power with a small-range meter to avoid damage to the meter. Therefore, when selecting the instrument, you must carefully observe the rated voltage, rated current and rated power that the instrument and equipment are allowed to withstand.
Dual Function Key Switches
Dual Function interlock Key Switches is a Key Switches that combines Electric Key Switch and Mechanical Key Lock, which is Simultaneously have power control and could mechanically protect the equipment from invading.
Our company's Key Lock Electrical Switches has mounting dimensions of 12mm and 19mm. This 2 Position Key Switch is widely used in the field of security products, which not only can achieve the function of switching power supply but also could protect customer`s confidential data.Application including buses, cars, motorcycles, ATM and so on.
Below are the specifications:
Electrical and row piece dual function
Zinc alloy die cast housing and cylinder
Barrel chrome or nickel plated standard
Lock case, white iron cover
4 disc tumbler mechanism
Brass tubular keys or Bilateral bilateral milling copper key, nickel plated
The iron bar has a standard size of 13mm or Row Piece, can be made according to customer requirements.
Key may be withdraws in one or both position aSilver terminals and Contacts.
Dual-Function Switches,Dual Push Button Switch,Automatic Transfer Switch,Changeover Switch
YESWITCH ELECTRONICS CO., LTD. , https://www.yeswitches.com