CAH05A1AD
Lead Time: 10 Days
Description Of Function
Overcurrent Sensing
After input voltage is applied & the sensing delay on power-up (ts) is completed, the unit will begin sensing for a fault condition. A fault will occur when the monitored AC current (I) goes above the Fault Trip Current setting & remains above the Reset level for a period longer than the adjustable time delay period (t). The LED will turn ON immediately and the relay will energize after the time delay on pick-up (t) is completed. The relay will de-energize & the LED will turn OFF when the monitored AC current goes below the Reset level.
Undercurrent Sensing
After input voltage is applied & the sensing delay on power-up (ts) is completed, the unit will begin sensing for a fault condition. A fault will occur when the monitored AC current (I) goes below the Fault Trip Current setting & remains below the Reset level for a period longer than the adjustable time delay period (t). The LED will turn ON immediately and the relay will energize after the time delay on pick-up (t) is completed. The relay will de-energize & the LED will turn OFF when the monitored AC current goes above the Reset level.
Function Chart

Product Overview
Features
- Detects either an Overcurrent or Undercurrent Fault (selectable)
- Monitors single phase AC current
- Three separate adjustable Fault Trip Current ranges covering 0.5 - 50 amperes
- Built-in toroidal through-hole current transformer allows easy access & multiple loops for increased sensitivity
- Adjustable time delay on fault trip
- LED indicates fault condition
- 10A SPDT output contacts
- Encapsulated for protection in harsh environments
Enclosure Style
Encapsulated 2.5" x 3.5" enclosure with dual screw mounting
Configuration / Contact Rating
- SPDT
- 10 Amperes @ 240VAC, General Purpose; 8 Amperes @ 28VDC, Resistive; 1/4HP @ 120/240VAC; B300
Application Information
- Voltage Tolerance: AC Operation: +10/-15% of nominal at 50/60 Hz.
- Load (Burden): 2 VA for all voltages
- Indicator LEDs: Red ON Steady when Fault occurs
- Current Sensing CAH05A:
Range: 0.5-5A
Type: Toroidal, through hole wiring
Setting Accuracy: Min: +0%, -50%; Max: +10%, -0%
Maximum Allowable Current: Steady-25A Turns; 150A Inrush for 10 Seconds
Trip Point Hysteresis: -5% Overcurrent sensing +5% Undercurrent sensing - Current Sensing CAH20A:
Range: 2-20A
Type: Toroidal, through hole wiring
Setting Accuracy: Min: +0%, -50%; Max: +10%, -0%
Maximum Allowable Current: Steady-50A Turns; 300A Inrush for 10 Seconds
Trip Point Hysteresis: -5% Overcurrent sensing +5% Undercurrent sensing - Current Sensing CAH50A:
Range: 5-50A
Type: Toroidal, through hole wiring
Setting Accuracy: Min: +0%, -50%; Max: +10%, -0%
Maximum Allowable Current: Steady-50A Turns; 300A Inrush for 10 Seconds
Trip Point Hysteresis: -5% Overcurrent sensing +5% Undercurrent sensing - Response Times:
Trip Delay (Relay ON): A: 0.150 - 7 Sec; B: 0.5 - 50 Sec; F: Fixed times i.e., F2 = Fixed 2 Sec
Sensing Delay on Start-up: C: No Delay, D: 1 Sec, E: 2 Sec, F: 3 Sec, G: 4 Sec, H: 5 Sec, J: 6 Sec
Time Delay on Reset (Relay OFF): 100ms
Reset Time: 400ms - Output Contacts: 10 Amperes @ 240VAC, General Purpose; 8 Amperes @ 28VDC, Resistive; 1/4HP @ 120/240VAC; B300
- Life: Mechanical: 10,000,000 operations; Full Load: 100,000 operations
- Temperature: -28° to 65° C (-18° to 149° F)
Approvals
Operation
The CAH Series is an AC current sensing relay that can detect either an overcurrent or undercurrent fault (selectable). The current-carrying wire is run through the built-in toroidal current transformer and can be looped multiple times for greater sensitivity. These relays include user-adjustable settings for Fault Trip Current & Time Delay on Fault Trip as well as an LED to indicate fault condition. The encapsulated construction offers protection in harsh environments. Applications such as monitoring for locked rotor or load loss condition, open heater or lamp, and process control are perfect for these products.
Overcurrent Sensing
After input voltage is applied & the sensing delay on power-up (ts) is completed, the unit will begin sensing for a fault condition. A fault will occur when the monitored AC current (I) goes above the Fault Trip Current setting & remains above the Reset level for a period longer than the adjustable time delay period (t). The LED will turn ON immediately and the relay will energize after the time delay on pick-up (t) is completed. The relay will de-energize & the LED will turn OFF when the monitored AC current goes below the Reset level.
Undercurrent Sensing
After input voltage is applied & the sensing delay on power-up (ts) is completed, the unit will begin sensing for a fault condition. A fault will occur when the monitored AC current (I) goes below the Fault Trip Current setting & remains below the Reset level for a period longer than the adjustable time delay period (t). The LED will turn ON immediately and the relay will energize after the time delay on pick-up (t) is completed. The relay will de-energize & the LED will turn OFF when the monitored AC current goes above the Reset level.
File Downloads
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Digital Catalog
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901-0000-287 Installation Instructions CAH, COH & CUH Series
Instruction Sheet
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CAH-COH-CUH eCAD Package
CAD Drawing