Protection Relays Current Monitoring Relays and Transducers ECSW SERIES Current Sensors Description The ECSW Series of single-phase, AC window, current sensors includes adjustable overcurrent and undercurrent trip points. Detects locked rotor, jam, loss of load, an open heater or lamp load, a broken belt, or loss of suction. LEDs aid in trip point adjustment and provide fault indication. The built-in toroidal sensor eliminates the need for an external current transformer. The output can be electrically latched after a fault, or automatically reset. Remote resetting of a latched output by removing input voltage. The unit includes switch selectable zero current detection and normally de-energized or energized output operation. Time delays are included to improve operation Wiring Diagram and eliminate nuisance tripping. Features & Benefits FEATURES BENEFITS Eliminates need to install stand alone Built-in toroidal current transformer and provides isolation from current sensing monitored circuit Encapsulated Protects against shock, vibration, and humidity Visual indication for trip point adjustment and fault L1 LED indication indication User selectable zero current detection, latched, Multiple switch N/L2 normally de-energized, or energized output adds selectable features application flexibility Eliminates nuisance tripping and prevents Adjustable trip delay MC = Motor Contactor RSW = Reset Switch rapid cycling M = Motor FSW = Fan or Float Contacts Isolated 10A, SPDT F = Fuses CR = Control Relay Allows control of loads for AC or DC voltages output contacts OL = Overload CS = Current Sensor MCC = Motor Contactor Coil Operation When the input voltage is applied, sensing delay on startup begins and the output transfers (if normally energized is V = Voltage selected). Upon completion of the startup delay, sensing of I> = Adjustable Overcurrent the monitored current begins. As long as current is above I< = Adjustable Undercurrent undercurrent trip point and below the overcurrent trip point W = Monitored Wire (inside the window), the output relay remains in its normal T - Adjustable Trip Delay operating condition and both red LEDs are OFF. The green LED glows when the output is energized. If current varies outside the window, the associated red LED glows, and the trip delay begins. If the current remains outside the window for the full Ordering Information MODEL INPUT VOLTAGE TRIP POINT ADJUST. TRIP DELAY SENSING DELAY ON STARTUP CONNECT. 24VDC ECSW3LABT 0.5 - 5A 0.150 - 7s 0.1s Terminal blocks ECSW4HBHT 120VAC 5 - 50A 0.5 - 50s 6s Terminal blocks ECSW4LADT 120VAC 0.5 - 5A 0.150 - 7s 2s Terminal blocks 120VAC ECSW4LBHT 0.5 - 5A 0.5 - 50s 6s Terminal blocks ECSW4MACT 120VAC 2 - 20A 0.150 - 7s 1s Terminal blocks ECSW4MBHT 120VAC 2 - 20A 0.5 - 50s 6s Terminal blocks ECSW4MBGT 120VAC 2 - 20A 0.5 - 50s 5s Terminal blocks 230VAC ECSW6MBHT 2 - 20A 0.5 - 50s 6s Terminal blocks If you dont find the part you need, call us for a custom product 800-843-8848 2016 Littelfuse Protection Relays & Controls Rev: 1-A-062716 wwwwww.littelfuse.com/.littelfuse.com/ecswProtection Relays Current Monitoring Relays and Transducers ECSW SERIES trip delay, the relay transfers to fault condition state. If the for the full trip delay, the normally open (NO) contact will current returns to normal levels (inside the window) during the close, energizing the control relay (CR) coil. The CR normally trip delay, the red LED goes OFF, the trip delay is reset, and the closed contact (CR1) opens and the MCC de-energizes and output remains in the normal condition. CR latches on through its normally open contacts (CR2). Reset is accomplished by momentarily opening the normally closed Reset: Remove input voltage or open latch switch. If zero reset switch (RSW). current detection is selected, the unit will reset as soon as zero current is detected. Note: If the current falls to zero within the trip delay, the ECSW remains de-energized. The sensing delay on startup occurs Operation With Zero Current Detection Enabled: If the when input voltage is applied therefore trip delay must be longer current decreases to zero within the trip delay period, then than the duration of the motors inrush current. The external zero current is viewed as an acceptable current level. The units latching relay CR2 is required in this system to prevent rapid output remains in its normal operating state. This allows the cycling. A timer can be added to provide an automatic reset. monitored load to cycle ON and OFF without nuisance tripping the ECSW. Zero current is defined as current flow of less than 250 milliamp-turns. Selector Switch Note: When zero current detect is selected, the latching ON OFF operation of switch SW2 is canceled the output will not latch after a fault trip. Not Used Notes on Operation SW1 Latched 1. There is no hysteresis on the trip points. The overcurrent SW2 Zero I and undercurrent trip points should be adjusted to provide SW3 Output - Normally Energized adequate protection against short cycling. 2. If the upper setpoint is set below the lower setpoint, both Mode Selection Switches red LEDs will glow indicating a setting error. SW1 = Latched or Auto reset selector OFF - Automatic reset after a fault 3. If zero current detection is selected (SW2 ON), and the ON - Output relay latches after a fault trips the unit system is wired to disconnect the monitored load, the SW2 = Zero current detection (below 250 mA) system may short cycle. After the unit trips, the load de- OFF - Zero current detection disabled energizes, and zero current is detected. The ECSW resets, ON - Zero current detection enabled and the load energizes again immediately and may be SW3 = Output during normal operation short cycled. OFF - Output relay de-energized ON - Output relay energized 4. The sensing delay on start up only occurs when input voltage is applied. When zero current detection is selected, the trip delay must be longer than the duration of the inrush current or the unit will trip on the inrush current. Typical Pump or Fan Protection Circuit Operation Window Current Sensing: With the ECSW connected as shown in the diagram, a load may be monitored and controlled for over and undercurrent. The ECSW Series on board CT (CS) may be placed on the line or load side of the contactor. The ECSW selection switches are set for zero current sensing (see Selector Switch SW2) and the output selection is normally de- energized (see Selector Switch SW3). The input voltage (V) is applied to the ECSW continually. As the control switch (FSW) is closed, the input voltage (V) is applied to the motor contactor coil (MCC), and the motor (M) energizes. As long as the current remains below the overcurrent and above the undercurrent trip points, the ECSWs output contacts remain de-energized. If the load current should rise above or fall below a trip point, 2016 Littelfuse Protection Relays & Controls Rev: 1-A-062716 wwwwww.littelfuse.com/ecsw.littelfuse.com/