This CR Magnetics ground fault sensing relay has an internal transformer, requires a supply voltage of 120VAC, and is used for monitoring ground faults in power supply applications. This current sensing relay has a window for routing the current-carrying wire and a calibrated dial for setting the trip point. An adjustable delay-on timer provides stability. When current levels rise above the adjusted set point, the relay is tripped and starts the timer. Once the timer cycles, the relay is energized and turns the output to full on. The relay remains tripped (latched) until supply power is removed. It has an internal transformer for scaling the current up or down and a voltage reference circuit that provides a repeatable trip point. This ground fault sensing relay has an LED indicator that alerts the user when the relay is tripped and is suitable for monitoring motor ground faults, sensing early failure of heater elements, and protecting equipment.
||1 Form C (SPDT)
||100 ms. maximum
|Input supply power
||80 mA normal; 100 mA maximum
||20 amps maximum
|Maximum sensed current
||Continuous 200% full scale
||10 million operations at normal rated load
||100,000 operations at normal rated load
|Initial contact resistance
||50 milliohms maximum at 500 mA, 12VDC
|Frequency (at 60 Hz)
||50 to 400 Hz
||-30 to +70 degrees C
||-55 to +85 degrees C
||3 1/4" male QC
||UL (Underwriter's Laboratories)
RoHS (Restriction on Hazardous Substances)
CSA (Canadian Standards Association)
Relay switches (also called an electrical relay or an electrical relay switch) use a small amount of power to control a larger source of power connected to electrical devices such as car motors, computers, and lighting installations. A basic relay switch has a control circuit with an electromagnetic coil and a load circuit with contacts and a lever. When current flows into the relay switch, it moves through the coil and a magnetic field is created, which causes the lever in the load circuit to move between contacts, either turning the device on or off. In a normally open (NO) relay switch, when power is supplied to the relay, the load circuit is closed and the power source connected to the relay is turned on. In a normally closed (NC) relay switch, when power is supplied to the relay, the load circuit is open and the power source connected to the relay is turned off. In other types of relay switches, non-moving parts such as transistors or semiconductors can be used as the control circuit to operate the switching mechanism. Relay switches can be controlled with an external switch, such as a light switch, or they can be connected to an automatically switched power source, such as a car ignition. One relay can operate multiple switches, and multiple relays can be operated with a single switch, with each relay operating independently from the other relays in the system.
CR Magnetics manufactures electrical sensors, indicators, and displays. The company, founded in 2004, is headquartered in Saint Louis, MO.