The R310A Current Sensing Switch is designed to sense alternating current in a conductor that passes through its opening. The R310A sensor closes an electronic switch if the alternating current in the conductor exceeds 0.5 amperes. Thus, the R310A switch may be used for several purposes:
- switch a pilot circuit
- energize a run signal on a device such as a fan, motor, or pump
- monitor motors and electrical loads for proper operation
- monitor on/off status of process motors
The R310A Series Current Sensing Switch is available in two models. The R310AD-1 switch is for use in low-voltage applications, such as with the P445 Electronic Lube Oil Control. The R310AE-2 switch is for use in high-voltage applications, such as with the P28 and P45 Electromechanical Lube Oil Controls.
The R310A switch avoids nuisance lockouts by sensing the lack of current flow to the motor. Regardless of the reason for motor shutdown, the lube oil control time delay circuit is de-energized when the current flow in the motor supply line drops below 0.5 amperes.
In a typical application, the lube oil control does not lock out when the control circuit shuts off the compressor. However, if the compressor overheats and the internal thermal overload circuits open, the compressor shuts itself down, which causes the oil pressure to drop. This drop in oil pressure will energize the lube oil control heater (P28, P45) or timer (P445), causing a nuisance lockout. In this situation, the R310 switch senses the lack of current to the motor, and is used to de-energize the time delay heater (P28, P45) or electronic timer (P445) before a nuisance lockout occurs.