Electromagnetic Relay Technical Reference
- Nov 03, 2017 -

Rated working voltage


Refers to the normal operation of the relay coil voltage. Depending on the type of relay can be AC voltage, it can be DC voltage.


DC Resistance


Refers to the coil in the relay DC resistance, can be measured by a multimeter.


Pull current


Refers to the relay can produce the minimum pull-in current. In normal use, the given current must be slightly larger than the pull-in current, so that the relay can work stably. As for the coil plus the operating voltage, generally not more than 1.5 times the rated operating voltage, otherwise it will have a larger current and the coil burned.


Release the current


Refers to the relay to generate the maximum current release action. When the relay pull-in state of the current is reduced to a certain extent, the relay will be restored to the power-off state. The current at this time is much smaller than the pull-in current.


Contacts switch voltage and current


Refers to the relay allows the voltage and current load. It determines the size of the relay can control the voltage and current, when used can not exceed this value, otherwise it is easy to damage the relay contacts.


3 test edit

Measured contact resistance


With the resistance of the multi-file file, measuring the normally closed contact and moving point resistance, the resistance should be 0; and normally open contact and moving point resistance is infinite. Which can be distinguished which is normally closed contact, which is normally open contact.


Measuring coil resistance


Available R × 10Ω file measuring relay coil resistance, in order to determine whether the existence of the coil open circuit phenomenon.


Measure the pull-in voltage and pull-in current


Find adjustable power supply and ammeter, a set of input voltage to the relay, and the power supply circuit in series into the ammeter to monitor. Slowly increase the power supply voltage, hear the relay pull the sound, note the pull-in voltage and pull-in current. For accuracy, how often can I try and average?


Measure the release voltage and release the current


Also connected as above test, when the relay occurs after the suction, and then gradually reduce the supply voltage, when you hear the relay to release the sound again, note the voltage and current at this time, you can try a few times to achieve an average release Voltage and release current. Under normal circumstances, the relay release voltage is about 10 ~ 50% of the pull-in voltage, if the release voltage is too small (less than 1/10 pull-in voltage), you can not normally use, it will threaten the stability of the circuit Work is not reliable.