The Macromatic CAH20A2BD is a current sensing relay. This encapsulated relay has an input voltage of 120V AC. It is made to monitor for over or undercurrent faults and has an output of 10A SPDT. It monitors AC current, with an adjustable range of 2-20A and a trip time delay of 0.5-50 seconds. There is a 1 second sensing time delay on startup. The built-in current transformer promotes greater access and sensitivity, as the wire can be looped around more than once. The encapsulated housing is intended for use in harsher conditions. Note: Image is an approximation. Actual part may differ.

Specifications

• Relay Function- Over/undercurrent
• Current Monitor Range- 2-20A
• Time Trip Delay- 0.5-50 seconds
• Sensing Time Delay on Startup- 1 Second
• Input Voltage- 120V AC
• 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 user selects whether the relay looks for over or under current errors using the switch. The relay starts monitoring for faults once the input voltage is applied and the startup time delay has passed. If an overcurrent error is found, the AC current rises above the set Fault Trip Current for longer than the adjusted time delay. The relay energizes after the time delay and remains that way until the current falls below the reset level. If an undercurrent situation occurs, the current drops below the set Fault Trip Current for longer than the time delay. Again, the relay energizes after the time delay and will de-energize once the current goes back over the reset level. The CAH20A2BD has an LED which glows red to indicate that a fault is found. Has pilot duty rating. Application examples include process control, monitoring for locked rotor or load loss, or open heater or lamp.

Macromatic CAH Series Relay Installation Manual

CAH20A2BD Macromatic 2-20A Encapsulated Current Sensing Relay