Water Billing System
Relay Technical Information
Definition of Relay Terminology
COIL
(also referred to as primary or input) • Nominal Coil Voltage (Rated Coil Voltage) A single value (or narrow range) of source voltage intended by design to be applied to the coil or input. • Pick-Up Voltage (Pull-In Voltage or Must Operate Voltage) As the voltage on an unoperated relay is increased, the value at or below which all contacts must function (transfer). • Drop-Out Voltage (Release or Must Release Voltage) As the voltage on an operated relay is decreased, the value at or above which all contacts must revert to their unoperated position. • Maximum Continuous Voltage The maximum voltage that can be applied continuously to the coil without causing damage. Short duration spikes • Coil Designation
Single side stable type Non-polarized Polarized 1 coil latching type
—
of a higher voltage may be tolerable, but this should not be assumed without first checking with the manufacturer. • Nominal Operating Current The value of current flow in the coil when nominal voltage is impressed on the coil • Nominal Operating Power The value of power used by the coil at nominal voltage. For DC coils expressed in watts; AC expressed as volt amperes. Nominal Power (W or VA) = Nominal Voltage × Nominal Current. • Coil Resistance This is the DC resistance of the coil in DC type relays for the temperature conditions listed in the catalog. (Note that for certain types of relays, the DC resistance may be for temperatures other than the standard 20°C 68°F.)
2 coil latching type 4-terminal 3-terminal
—
+ or +
+
+ or —
+
—
+
—
—
—
+
A black coil represents the energized state. For latching relays, schematic diagrams generally show the coil in its reset state. Therefore, the coil symbol is also shown for the reset coil in its reset state.
CONTACTS (secondary or output)
• Contact Forms Denotes the contact mechanism and number of contacts in the contact circuit. • Contact
Definition of Relay Terminology
COIL
(also referred to as primary or input) • Nominal Coil Voltage (Rated Coil Voltage) A single value (or narrow range) of source voltage intended by design to be applied to the coil or input. • Pick-Up Voltage (Pull-In Voltage or Must Operate Voltage) As the voltage on an unoperated relay is increased, the value at or below which all contacts must function (transfer). • Drop-Out Voltage (Release or Must Release Voltage) As the voltage on an operated relay is decreased, the value at or above which all contacts must revert to their unoperated position. • Maximum Continuous Voltage The maximum voltage that can be applied continuously to the coil without causing damage. Short duration spikes • Coil Designation
Single side stable type Non-polarized Polarized 1 coil latching type
—
of a higher voltage may be tolerable, but this should not be assumed without first checking with the manufacturer. • Nominal Operating Current The value of current flow in the coil when nominal voltage is impressed on the coil • Nominal Operating Power The value of power used by the coil at nominal voltage. For DC coils expressed in watts; AC expressed as volt amperes. Nominal Power (W or VA) = Nominal Voltage × Nominal Current. • Coil Resistance This is the DC resistance of the coil in DC type relays for the temperature conditions listed in the catalog. (Note that for certain types of relays, the DC resistance may be for temperatures other than the standard 20°C 68°F.)
2 coil latching type 4-terminal 3-terminal
—
+ or +
+
+ or —
+
—
+
—
—
—
+
A black coil represents the energized state. For latching relays, schematic diagrams generally show the coil in its reset state. Therefore, the coil symbol is also shown for the reset coil in its reset state.
CONTACTS (secondary or output)
• Contact Forms Denotes the contact mechanism and number of contacts in the contact circuit. • Contact