Selectable Overcurrent and Undercurrent Monitoring
A selector switch sets the monitoring function. In overcurrent mode, the relay energizes when AC current exceeds the selected fault trip point for longer than the trip delay. It remains energized until current falls below the reset level. In undercurrent mode, the relay energizes when current stays below the trip point for longer than the trip delay and de-energizes when current rises above the reset level.
Startup Sensing and Fault Trip Timing
The CAH05A2AH has a fixed 5 second startup sensing delay and a separate adjustable 0.15–7 second trip delay. The startup delay postpones current sensing when input power is applied. Once sensing begins, the trip delay determines how long a fault must persist before the output energizes.
Integrated Current Transformer and Construction
The integrated toroidal current transformer uses through-hole wiring. Looping the monitored conductor through the transformer more than once increases sensing sensitivity. The encapsulated housing suits demanding industrial environments, while surface mounting and male quick-connect terminals support control panel installation.
Features and Benefits
- Selectable monitoring function supports either high-current or low-current fault detection.
- Adjustable trip timing allows a sustained fault to trigger the output after the selected delay.
- A red LED provides a visible indication when a fault is detected.
- SPDT contacts and a B300 pilot duty rating support industrial control circuits.
- An integrated current transformer allows multiple conductor passes for greater sensitivity.
Applications
Use the CAH05A2AH for current-based process control and equipment monitoring. Overcurrent sensing can identify conditions associated with a locked rotor. Undercurrent sensing can help detect load loss or an open heater or lamp circuit. Select the monitoring mode, trip point, and delay to suit the equipment's normal operating current and startup behavior.
Installation and Selection Notes
- Confirm the 120V AC input requirement and the applicable output contact rating for the control circuit.
- Select overcurrent or undercurrent mode and set the fault trip point for the monitored load.
- Account for the number of conductor passes through the current transformer when setting the sensing threshold.
- Surface mount the relay with two #6 screws and connect wiring to the 0.25-inch male quick-connect terminals.
- Review the installation manual for wiring and adjustment procedures.
Installation Manual
Macromatic CAH Series Relay Installation Manual
