The ABB RXMVB 4 (RK 251 402-AP) is a heavy-duty, multi-contact auxiliary relay used in protection and control systems. It features a robust mechanical latching mechanism with two stable positions, ensuring contact state remains unchanged even during power loss to the operating coils.

 

Parameters

• Type: RXMVB 4
• Ordering Code: RK 251 402-AP
• Coil Voltage: Typically 110-125 V DC (standard for AP variant)
• Contact Configuration: 8-contact variant (multi-combination)
• Duty Cycle: Intermittent or continuous rating
• Mounting: COMBIFLEX plug-in system

 

Specifications

• Brand: ABB
• System: COMBIFLEX relay family
• Insulation Voltage: 2.0 kV (50 Hz, 1 min)
• Contact Material: Silver-plated or gold-plated options
• Operating Time: Less than 40 ms
• Weight: Approximately 0.7 kg

Applications

• Latching Functions: Memory circuits in substation control.
• Signal Multiplication: Increasing the number of available contacts for a single command.
• Remote Control: Switching of high-current or high-voltage inductive loads.
• Industrial Logic: Hard-wired interlocking and automation sequences.

 

Q&A

• Q: Is the RXMVB 4 a bistable relay?
  • A: Yes, it is a bistable (latching) relay with separate “Set” and “Reset” coils.
• Q: Can it be mounted on a standard DIN rail?
  • A: No, it requires a COMBIFLEX terminal base (RX 4) for proper integration.
• Q: Does it have manual override capability?
  • A: Yes, it includes a mechanical indicator and can often be manually operated via the front reset lever.