The Macromatic CAH20A8AD is a current sensing relay. This encapsulated relay has an input voltage of 24V AC/DC. It is designed to monitor for over or undercurrent faults and has an output of 10A SPDT. It checks AC current, with an adjustable range of 2-20A and a trip time delay of 0.15-7 seconds. There is a 1 second sensing time delay on startup. The current transformer is built-in, offering greater access and sensitivity, as the wire can be looped around more than once. Ideal for use in harsher environments, due to the encapsulated housing. Note: Image is an approximation. Actual part may differ.

Specifications

• Relay Function- Over/undercurrent
• Current Monitor Range- 2-20A
• Time Trip Delay- 0.15-7 seconds
• Sensing Time Delay on Startup- 1 Second
• Input Voltage- 24V AC/DC
• Output- 10A SPDT
• Input Voltage Tolerance- +10/-15% of nominal
• Load- 2VA
• Current Sensing- 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 Time- Time Delay on Reset (Relay OFF): 100ms
  Reset Time: 400ms
• Operating Temperature- -28 C to 65 C (-18 F to 149 F)
• Storage Temperature- -40 C to 85 C (-40 F to 185 F)
• 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
• Mounting- Surface mount with two #6 screws
• Termination- 0.25" male quick-connect terminals
• Overall Dimensions- 3.5" Height x 2.5" Width x 1.5" Depth
• Approvals- UL & CUL Recognized

The relay starts checking for errors once the input voltage is applied and the startup time delay has passed. For an overcurrent condition, the AC current goes above the set Current Monitor Range for longer than the adjusted time delay. The relay energizes after the time delay and remains in that state until the current goes under the reset level. If an undercurrent error occurs, the current goes below the set Current Monitor Range for longer than the time delay. Again, the relay energizes after the time delay and will de-energize once the current goes over the reset level. The user chooses whether the relay monitors over or under current errors using the selector switch. The CAH20A8AD has an LED which is red to indicate when a fault has occurred. Has pilot duty rating. Examples of common applications include process control, monitoring for locked rotor or load loss, or open heater or lamp.

Macromatic CAH Series Relay Installation Manual

Macromatic CAH20A8AD Current Sensing Relay