The Macromatic CAH20A1BD is a current sensing relay. This encapsulated relay has an input voltage of 240V AC. It is made to check 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 offers easier access and greater sensitivity, as the wire can be looped several times. The encapsulated casing is ideal for harsh environments. 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- 240V 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 selector switch allows the user to choose whether the relay checks for over or under current errors. The relay starts monitoring for faults once the input voltage is introduced and the startup time delay has passed. If an overcurrent fault occurs, the AC current goes above the set Fault Trip Current for longer than the adjusted time delay. The relay energizes after the time delay and stays energized until the current goes below the reset level. In the case of an undercurrent fault, the current needs to go under 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 over the reset level. The CAH20A1BD has an LED indicator which glows red to display when a fault is detected. Has pilot duty rating. Common applications include process control, monitoring for locked rotor or load loss, or open heater or lamp.

Macromatic CAH Series Relay Installation Manual

Over and Undercurrent Sensing Relay Macromatic CAH20A1BD