Electromagnetic relay selection
Characteristic parameters: The main characteristics of the electromagnetic relay parameters are the following: 1. Rated operating voltage or rated current: This refers to the relay work coil voltage or current required. The construction of a type of relay is generally the same. In order to adapt to different voltage circuit applications, a type of relay usually has a variety of rated operating voltage or rated operating current, and with the specification model to be distinguished. 2. DC resistance: This refers to the DC resistance of the coil. Some product specifications are given rated operating voltage and DC resistance, then according to Ohm law to find the rated operating current. If the rated operating current and DC resistance are known, the rated operating voltage can also be obtained. 3. Pull-in current: it refers to the relay can produce the minimum action of the suction action. In actual use, to make the relay reliable pull, the given voltage can be equal to or slightly higher than the rated operating voltage. Generally not more than 1.5 times the rated operating voltage. Otherwise it will burn the coil. 4. Release current: it refers to the maximum current that the relay produces the release action. If the current of the relay in the pull-up state is reduced, when the current is reduced to a certain extent, the relay returns to the state when it is not energized. This process is called the release operation of the relay. The release current is much smaller than the pull-in current.
① control circuit power supply voltage, can provide the maximum current;
② the voltage and current in the controlled circuit;
③ charged circuit needs several groups, what form of contact. When using the relay, the general control circuit power supply voltage can be used as the basis for selection. The control circuit should be able to provide sufficient operating current to the relay, otherwise the relay pull is unstable. If used for general use of electrical appliances, in addition to considering the chassis volume, the small relay to consider the main layout of the circuit board installation. For small appliances, such as toys, remote control devices should be used ultra-small relay products.
