One: preliminary judgment of product quality
1: The first step of is to look at the appearance of the car relay. The appearance of a good car relay must be done well.
2: The second step is to see whether the production process of the car relay (part riveting, cleanliness, plating of parts, etc.) is good or not, and a good car relay production process must be done well.
3: The third step is the professional technical parameters of the car relay, such as point alignment, contact gap, over-travel, pull-in voltage, release voltage, etc.
4: The fourth step is to go through a professional relay test bench to test the life of electrical appliances.
Two: material part
1: The black shell is PA66 nylon material, the base is reinforced with 25-30% PA66 nylon material, the transparent shell is PC polycarbon material, and the coil frame is PBT
2: The feet are divided into iron feet, brass feet, and copper feet
Performance analysis: red copper has the strongest conductivity and heat dissipation, brass H62 is second, iron is the worst, and iron will rust.
Iron can be brass plated (yellow), tin plated (white), nickel plated (white), copper plated (red), etc., brass can be pickled (yellow), tin plated, copper plated, etc., copper can be acid washed (red), tin plating and other treatments.
Replacing the 85 and 86 feet with iron feet has no effect on the quality. The coil current is relatively small at about 0.15A. I am afraid that it will rust for too long. 30,87,87a are conductive pins, and the contact current passing through is larger (20A-80A). The material has a greater influence.
3: Contacts are divided into copper dot silver plating, silver cadmium oxide (Agcdo), silver tin oxide (Agsno), silver tin indium oxide (Agsno In), etc.
Performance analysis: Copper spot silver plating has the worst life. Silver cadmium oxide (Agcdo) life is generally 5-8W times, silver cadmium oxide is silver and cadmium metal alloy, Agcdo 15, silver content 85%, silver layer thickness is about 0.2 thick (20 wire thickness). Silver tin oxide (Agsno) life is more than 8W times or 8-10W times, silver tin oxide is silver and tin metal alloy, Agsno 12 is silver content 88%, silver layer thickness is about 0.25-0.3 thick (25-30 wire) . Silver indium tin oxide (Agsno In) is the best.
4: The yoke is A3 electro-galvanized, the suction plate and iron core are pure iron DT4C, which has undergone high temperature demagnetization treatment.
5: The moving reed is high-precision phosphor copper Qsn6.5, imported red copper 7035, imported beryllium bronze
Performance analysis: (1) The best material for moving reeds is beryllium bronze, followed by imported red copper 7035, and high-precision phosphor copper for ordinary products
(2) Phosphor copper has a pattern, and the discharge of the moving reed mold should follow the pattern. The angle of the control pressure is perpendicular to the pattern. The mechanical life (moving reed fatigue) life can reach 1,000 W times, and the mold is discharged horizontally, the angle of the control pressure is parallel to the line forming, and the reed is easy to break. For comparison, the cut beef has grains.
(3) The function of the red copper shunt wire is the current and heat generated by the energization of the shunt contact. The deformation of the trial reed becomes less, and the wire is spot welded on the head of the reed. After the power is turned on, the color of the wire becomes dark red, then gray, and then changes. Black, the moving reed is only a little bit red on the head and then black. The key forming part will only become slightly red and will not be seriously deformed. It will not affect the over-travel and performance of the relay, and greatly improve the quality of the relay.
6: The enameled wire is copper wire QA-155, 12V 0.12, 24V 0.08, national standard 12V 0.13, 24V 0.09, but due to production cost issues, 0.12, 0.08 is used. Many companies with low prices use copper-clad aluminum enameled wire, distinguishing between the two A kind of enameled wire method, burn it with a lighter. The copper enameled wire will turn black after red and will not break. The black and black one is the same as the original one. The copper clad aluminum enameled wire will become white and the wire will be broken into many segments. The copper clad aluminum enameled wire is energized A few times there was no suction, and the relay was scrapped.
Three: technical parameters
1: The relay usually has two circuits
The first 85,86 pin coil loop, 12V relay as an example, automotive relay power P is generally 1.8W, 1.6W (usually produced according to 1.8W), 1.8W standard resistance is 80 ohms, production standard is 75 -85 ohms (plus and minus 5 ohms), most manufacturers have negative tolerances, 85/86 loop current 12/80=0.15A.
The second 30, 87, 87a pin contact circuit, 12V relay as an example, the current is the contact current 40A, 30A, 80A, etc.
2: Control of pull-in voltage and release voltage
12V 5.5—7.2V, 24V 11—14.4V
Release 12V 1.2V-3.6V 24V 2.4V-7.2V
3: Overstroke, up pressure, down pressure
Overtravel is the distance between the iron core and the suction plate after the static point and the moving point are closed, strictly controlled between 0.15-0.25
The upper pressure is the pressure at the moment when the moving point leaves the upper static point, and is controlled to be greater than 0.3g
The down pressure is the pressure at which the moving point leaves the lower static point after the relay pulls in. The coil and the iron core material determine the magnitude of the down pressure. If the product contacts pull in, the iron core does not pull in the suction plate, the down pressure is very small, the product Life expectancy is greatly reduced.
4: contact gap 40A contact gap is generally about 0.4-0.6, 80A contact gap is generally about 0.6-0.8, the contact gap is a little larger
5: Contact form 1A, 1B, 1C, 1U, 2A, double contact and other forms.
6: Mechanical life, electrical life
The mechanical life is the life of the moving reed under no-load test when the relay contact is not loaded with current, which is generally 10 million times.
The electrical life is the relay life test under the condition that the relay contact is loaded with current. The life is 100,000 times. The relay life of tens of thousands of times asked by the customer usually refers to the electrical life.