Panasonic Electric Works Obihiro Co., Ltd. Oct. 1, 2008: 1st Edition 1 Automotive Relay User’s Guide Please use the check sheet. Category Section Contents 1. Confirmation under the actual use condition 2. Safety precautions 1. Confirmation under the actual use The rated switching power and life mentioned in the specification and catalog are given only as guides. A relay may encounter a variety of ambient conditions during actual use resulting in unexpected failure.
4. Load, Electrical life 1. General 2. Inductive load 3. Lamp load 4.Electricdischarge lamp load 5. LED lamp load 6. Other lamp load 7. Motor load 8. Capacitor load 9. Resistance load 10. Small electric current load 11. Load polarity 12.
. Load, Electrical life 13. Load voltage 14. Coil voltage 15. Coil short-pulse input 3 If the load voltage is high, the arc energy which generated at contact switching increases, which may decrease the electrical life. Therefore, it is necessary to give consideration to the voltage which could occur in actual use condition. If coil applied voltage gets higher, the relay operate time gets faster. However, contact bounce gets also larger so that the electrical life may decrease.
4. Load, electrical life 22. Contact protective circuit 4 Use of contact protective devices or protection circuits can suppress the counter emf to a low level. However, note that incorrect use will result in an adverse effect. Typical contact protection circuits are given in the table below. Also, note that release time will slow down due to sneak in the circuit and may cause the electrical life to shorten and slight-welding.
4. Load, electrical life 23. Connection of load 5 Connect the load to one side of the power supply as shown in Fig. (a). Connect the contacts to the other side. This prevents high voltages from developing between contacts. If contacts are connected to both side of the power supply as shown in Fig. (b), there is a risk of shorting of the power supply when relatively close contacts short. Fig.
5. Coil impressed voltage 6. Coil impressed circuit 4.Twin-relay coil simultaneous operation 5. Continuous current 1. Relay drive by means of a transistor 6 For relays which have multiple coils such as twin relay for forward-reverse operation of motor, if the coils are continuously turned on at the same time, the coil temperature may exceed the tolerance in a short time due to heat generation of each coil. Please contact us before use.
6. Coil impressed circuit 1. Relay drive by means of a transistor 7 3. Snap action (Characteristic of relay with voltage rise and fall) It is necessary for the relay coil not to impress voltage slowly but to impress the rated voltage in a short time and also to drop the voltage to zero in a short time. Non-pulse signal Pulse signal (square wave) (No good) Without snap action (Good) Snap action 4.
6. Coil impressed circuit 1. Relay drive by means of a transistor 8 6. Residual Coil Voltage In switching applications where a semiconductor (transistor, UJT, etc.) is connected to the coil, a residual voltage is retained at the relay coil which may cause incomplete restoration and faulty operation.
７. Contact reliability 8. Contact resistance 9. Operate noise 10.Mechanical noise 1. Load switch 9 When switching with a very small load after switching with a large load, “contact failure by small load switching” may occur due to particles generated during switching of the contact with large load. Please note that or contact us. 2.
12. Usage ambient condition 1.Temperature, humidity, air pressure 2. Dust 3. Silicon 4. Magnetism 5. Vibration 6. Shock 7. Dew condensation 10 During usage, storage, or transportation, avoid locations subject to direct sunlight and maintain normal temperature, humidity, and pressure conditions. The allowable specifications for environments suitable for usage, storage, and transportation are given below. 1.
. Usage ambient condition 8. Water resistance 9. Freezing 13.Installation 14. PC board design 10. Low temperature, low humidity 1. Connector installation 1. PC board design consideration 11 Select the sealed-type for exposure to water. In the case of water exposure in severe conditions or immersion, please verify water resistance of the relay or contact us. Even for sealed-type relays, its terminals are not waterproof, so please avoid a failure such as terminal corrosion.
14. PC board design 2. Hole and Land diameter 12 The Hole and Land diameter are made with the hole slightly larger than the lead wire so that the component may be inserted easily. Also, when soldering, the solder will build up in an eyelet condition, increasing the mounting strength. The standard dimensions for the Hole diameter and Land are shown in the table below. Standard dimensions for the Hole and Land diameter Unit: mm/ inch Standard Hole Tolerance Land diameter di t 0.8/ .031 2.0 to 3.0/ .079 to .
13 15. PCB 1. Through-hole type mounting In keeping with making devices compact, it is becoming more common to solder the relay to a PC board along with the semiconductors instead of using the previous plug-in type in which relays were plugged into sockets. With this style, loss of function may occur because of seepage into the relay of flux, which is applied to the PC board. Therefore, the following precautions are provided for soldering a relay onto a PC board.
14 4. Soldering Automatic Soldering • Flow solder is the optimum method for soldering. • Adjust the level of solder so that it does not overflow onto the top of the PC board. • Unless otherwise specified, solder under the following conditions depending on the type of relay. Solder Temperature Soldering Time 5. Cooling Approx.260°C±5°C/ 500°F±41°F Within approx. 6 seconds Hand Soldering • Please take caution with multi-layer boards.
15 15. PCB mounting 2. SMD type To meet the market demand for downsizing to smaller, lighter, and thinner products, PC boards also need to proceed from insertion mounting to surface mounting technology. To meet this need, we offer a line of surface mount relays. The following describes some cautions required for surface mount relay installation to prevent malfunction and incorrect operation. *Please contact us for or reflow soldering of through-hole terminal type. 1. What is a Surface Mount Relay? 1.
16 3. Examples of SMT Applications IRS is the most popular reflow soldering technology now available for surface mounting. It uses a sheath heater or infrared lamp as its heat source. PC board assemblies are continuously soldered as they are transferred through a tunnel furnace comprised of a preheating, heating, and cooling-stages. 1.
17 3. Reflow Reflow soldering under inadequate soldering conditions may result in unreliable relay performance or even physical damage to the relay (even if the relay is of surface mount type with high heat resistance). 1.IRS profile Note: When a soldering technique other than above is to be used (hot air, hotplate, laser, or pulse heater technique), carefully investigate the suitability of the technique. The soldering temperature profile indicates the pad temperature.
18 16. Soldering 1. Solder Please use the flux-resistant type or sealed type in the case of automatic soldering. 2. Cleaning Please use the sealed type for cleaning. Also, use the alcohol type for cleaning liquid and avoid ultrasonic cleaning. When cleaning a printed circuit board after soldering, we recommend using alcohol-type cleaning liquid. Please avoid ultrasonic cleaning. The ultrasonic energy may cause breaking of coil and sticking of contacts.
19 19. Reliability [1] What is Reliability? 1. Reliability in a Narrow Sense of the Term In the industrial world, reliability is an index of how long a particular product serves without failure during use period. 2. Reliability in a Board Sense of the Term Every product has a finite service lifetime. This means that no product can continue normal service infinitely. When a product has broken down, the user may throw it away or repair it.
20 1. Degree of Reliability Degree of reliability represents percentage ratio of reliability. For example, if none of 10 light bulbs has failed for 100 hours, the degree of reliability defined in, 100 hours of time is 10/10 = 100%. If only three bulbs remained alive, the degree of reliability is 3/10 = 30%.
21 [3] Failure 1. What is Failure? Failure is defined as a state of system, equipment, or component in which part of all of its functions are impaired or lost. 2. Bathtub Curve Product's failure rate throughout its lifetime is depicted as a bathtub curve, as shown below. Failure rate is high at the beginning and end of its service lifetime. (I) Initial failure period The high failure rate in the initial failure period is derived from latent design errors, process errors, and many other causes..
22 3. Weibull Analysis Weibull analysis is often used for classifying a product's failure patterns and to determine its lifetime. Weibull distribution is expressed by the following equation: where Weibull distribution can be adopted to the actual failure rate distribution if the three variables above are estimated. The Weibull probability chart is a simpler alternative of complex calculation formulas.
Product name: Relay name: Check sheet (1/2) Date: Category Safety Check box □ Does the vehicle system have a fail-safe in case of a relay failure? □ Has it been confirmed by testing under actual load, actual circuit, and actual condition? Have load type, load current characteristic, and current value been checked? Isn't the applied contact current too small ? (Small current is likely to decrease the contact reliability.
Check sheet (2/2) Category Contact reliability Check box □ □ Check item Have precautions been checked in the case of switching with both high and low loads by the same contact? Doesn't heat dissipation occur under low temperature? Refer to the following page and item on Page / Category Section ｐ9/7-1 ｐ9/7-2 □ Has transient state of contact resistance been considered? ｐ9/8-1 □ Are contact voltage and current 6V 1A or higher? ｐ9/8-2 Operating sound □ Are there any problems regarding operating so
