1, the ambient temperature: ambient temperature and coil temperature on the operating voltage, the general sub-engine compartment (maximum temperature of 125 ℃) and the cockpit (maximum temperature of 85 ℃); relay coil resistance with temperature Changes and changes, which relay the action, the impact of the release voltage is obvious. Each rise in temperature 1 ℃, the coil resistance will rise 4 ‰. When the relay coil power for some time, the coil heat. At this time relay contact switching action, the action voltage is higher than the cold action voltage.
2, the operating voltage: transistors and integrated circuits used to drive the relay, pay attention to the voltage drop of transistors and integrated circuits and relay coil back EMF on the transistor and the destruction of integrated circuits.
3, the coil rated voltage: the normally open contacts in the relay closed, the general requirements of the coil should be applied above the minimum operating voltage of the voltage, the automotive relay is not recommended to use low hold voltage, because it will reduce the product vibration resistance, severe turbulence in the car Malfunction may occur.
4, the maximum operating voltage coil: Automotive relays to meet the requirements of low operating voltage (60% of the rated voltage), the general design of high power consumption, long-term applied to the coil voltage value should generally be less than 120% of the rated voltage, if required 130% of the rated voltage and above the value, the need to contact the relay manufacturer and obtain technical support. Especially at high temperatures, will cause the coil temperature is too high, accelerated aging - the final coil insulation damage, turn short turns and failure.
5, the release of voltage: Automotive relay release voltage is generally 10% of the rated voltage, when the remaining voltage on the line is too large, will cause the relay not to release.