The ABB 91A020 is a high-reliability auxiliary contact block designed for mounting on ABB contactors and motor starters. This component serves as a secondary switch that operates in tandem with the primary power contacts, providing essential feedback signals to control circuits, PLCs, or monitoring systems. Engineered for high switching frequency and long mechanical life, it ensures precise status signaling in complex automation sequences.
Product Technical Specifications
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Model Number: 91A020
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Contact Configuration: 2 Normally Open (2 NO)
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Rated Operational Voltage: Up to 690V AC / 440V DC
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Rated Operational Current (AC-15): 4A at 240V / 2A at 400V
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Rated Operational Current (DC-13): 0.55A at 125V / 0.27A at 250V
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Conventional Free-air Thermal Current ($I_{th}$): 10A
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Mounting Position: Front or Side mounting (model specific)
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Dimensions: 45mm x 32mm x 38mm
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Weight: 0.05 kg
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Country of Origin: France / Germany
Application Areas
The 91A020 is widely used in motor control centers (MCC), electrical distribution boards, and industrial automation panels. Its primary role is to provide auxiliary signaling for motor status (Running/Stopped), electrical interlocking between two contactors (e.g., in star-delta or reversing starters), and triggering remote indicator lights or alarm circuits. It is commonly found in HVAC systems, conveyor control, and pump station management.
Product Operating Instructions
Installation should be performed while the main power supply is isolated. To install the 91A020, align the clip-on mechanism with the mounting rails on the front or side of the compatible ABB contactor. Press firmly until the block clicks into place; this ensures the mechanical actuator of the contactor correctly engages the auxiliary contacts. Wire the control cables to the screw terminals according to your circuit diagram, ensuring that the torque does not exceed the manufacturer’s specification to avoid stripping the threads. For maintenance, periodically inspect the terminals for tightness and check for signs of contact pitting if the unit is operating near its maximum electrical rating.
Common Questions & Answers
Q: Can I use the 91A020 for switching a small motor directly?
A: No, this is an auxiliary contact designed for control-level signals only. It does not have the arc-suppression capabilities or current rating to handle power loads like motors.
Q: What is the difference between “Normally Open” (NO) and “Normally Closed” (NC) in this context?
A: “Normally Open” means the auxiliary circuit is open (disconnected) when the main contactor is de-energized. When the contactor pulls in, the 91A020 contacts close, allowing current to flow through the signaling circuit.
Q: Does this block require any specific orientation for mounting?
A: While it can technically operate in multiple orientations, it must be mounted directly onto its compatible contactor body to ensure the mechanical plunger aligns correctly with the contactor’s moving armature.
Q: Is the 91A020 compatible with all ABB contactor series?
A: It is specifically designed for the older A-Line and related legacy series. For newer AF-Line contactors, a different series of auxiliary blocks (such as the CA4 series) is typically required.
Recommended Similar Models
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ABB 91A011 (1 NO + 1 NC)
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ABB 91A110 (2 NC)
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ABB CA5-10 (Front Mount NO)
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ABB CAL5-11 (Side Mount 1NO/1NC)
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ABB CA4-10 (AF Series Auxiliary)
