Coil Voltage of Relay
Coil Voltage of Relay
Before knowing how to choose the relay coil voltage, first of all, let us introduce: what is the relay’s coil voltage. Coil voltage refers to the rated voltage that the working line can supply to the relay coil in order to make the relay work reliably. It is an important parameter used to control contact action.
Then what are the coil voltages of relays? All the technical specifications can only be seen in the following four specifications.
Coil voltage or nominal voltage - for example, 12VDC - this is the nominal voltage of the operating coil although it is important to know this, it does not tell us all about the available voltage range.
Closing voltage (minimum) - for example 1.2VDC - This voltage specification indicates when the coil is no longer energized. Any voltage below this value will not enable the coil, and the contacts will not perform any action.
On/start voltage (maximum) - e.g. 9VDC - This specification specifies when the coil must be energized.At this voltage, the voltage on the coil must close the contact.
Maximum coil voltage - for example, 20.4VDC - this is the maximum voltage at which you can safely operate the coil. This is usually temperature dependent. For example, the part at 23 C has a voltage of 20.4VDC tolerance of 10%, but the safest approach is to be as close to the nominal voltage as possible.
Then among the above four specifications, which parameter is particularly important for us to choose a favorite relay, of course, nominal voltage. Taking the relay produced by IVY as an example, there are 6-48VDC available for users to choose, among which the most common ones should be 6/9/12VDC.
In order to make the relay work reliably, it is necessary to ensure that the working circuit can supply the rated voltage to the relay coil.When transistor drive relay is used, 4.5V relay is recommended to be used when transistor drive circuit voltage is 5V because the voltage drop inherent in the transistor will cause the voltage applied on the relay coil to be lower than the nominal value of the drive circuit.Sometimes in order to shorten the relay operation time, the maximum allowable voltage can be applied to the coil for a short period of time, but make sure that the relay does not overheat or even damage.
It is worth reminding that the rated operating voltage of the relay should be the same as the voltage in the circuit. The voltage in the circuit should not exceed the rated working voltage for a long time, otherwise the relay coil is easy to burn out. To learn more about relays and provide free technical support, visit www.ivy-metering.com.
