ABB UA16-30-10RA Capacitor Switching Contactor

2. Core Technical Specifications

3. Structural & Functional Features

3.1 Core Structure

Built-in Damping Resistor Module: 3 independent resistors connected in series to the main circuit, realizing capacitor pre-charging and limiting switching peak current to a safe level.

Special Contact Design: Main contacts adopt anti-welding alloy material to enhance arc erosion resistance and withstand frequent inrush current impact.

Mechanical Interlock Mechanism: Ensures resistors close before main contacts and open after main contacts, completing a full current-limiting protection cycle.

Modular Accessory System: Supports expansion with auxiliary contacts, surge suppressors and other accessories.

3.2 Key Functions

Inrush Current Suppression: Built-in resistors reduce switching inrush current from 100×In to about 10×In, greatly lowering contact ablation risk.

Reactor-Free Design: RA series with inherent current limiting; no need for external series reactors, saving installation space and cost.

Safe Operation: Capacitor bank must discharge to ≤50V before re-energization to prevent secondary inrush current caused by residual charge.

Signal Feedback: 1NO auxiliary contact for status indication and interlock control.

4. Optional Accessories List

5. Cross-Brand Equivalent & Replacement List

6. Selection Guidelines & Alternative Solutions

6.1 Key Selection Parameters

Capacitor Capacity: UA16-30-10RA suitable for 3-phase capacitor banks ≤12.5kVar@400V / ≤20kVar@600V.

Coil Voltage: Must match control supply voltage; common 220V/380V to avoid coil burnout.

Mounting: Confirm 35mm standard DIN rail; special bracket required for non-standard rails.

Environmental Conditions: Derate for high temperature (>40°C) with derating factor 0.8~0.9.

6.2 Recommended Alternative Solutions

6.3 Installation & Maintenance Notes

1. Before Installation: Ensure capacitors are fully discharged to ≤50V to avoid residual charge hazards.
2. Wiring: Main circuit wire cross-section ≥1.5mm²; control circuit ≥0.75mm²; ensure terminals are fully tightened.
3. Maintenance Cycle: Inspect contact wear every 6 months; recommend replacement after 100,000 cumulative operations.
4. Troubleshooting: If contactor fails to operate, first check coil voltage and control circuit fuse.

ABB UA16-30-10RA is a dedicated damping resistor built-in capacitor contactor designed for low-voltage reactive power compensation systems.

Three series resistors suppress switching inrush current, protecting contacts and extending service life.

With 16A AC-6b rating suitable for 12.5kVar capacitor banks at 400V, 3-pole NO main contacts plus 1NO auxiliary contact fully meet standard control requirements.

Compared with ordinary contactors, the RA series needs no external reactor and features simple installation, making it an ideal choice for industrial and building power distribution reactive compensation systems.

Complete Model List of ABB UA Series Capacitor Switching Contactors

1. Model Naming Rule

ABB UA series capacitor contactors adopt a unified naming format for quick parameter identification:

2. Full Model List by Current Rating

2.1 16A Series (≤12.5kVar @400V)

2.2 26A Series (≤20kVar @400V)

2.3 30A Series (≤25kVar @400V)

2.4 50A Series (≤40kVar @400V)

2.5 63A Series (≤50kVar @400V)

2.6 75A Series (≤60kVar @400V)

2.7 95A Series (≤75kVar @400V)

2.8 110A Series (≤90kVar @400V)

2.9 140A Series (≤110kVar @400V)

3. Coil Voltage Options (Universal for All Series)

4. Key Selection Instructions

4.1 Standard Type vs RA Built-in Resistor Type

Standard (Non-RA): Requires external reactor for inrush suppression; lower cost, suitable for systems with existing reactors.

RA Built-in Resistor Type: 3 built-in damping resistors reduce switching inrush from 100×In to approx.10×In; no extra components needed for easy installation.

4.2 Auxiliary Contact Selection

00: No auxiliary contacts, for simple control loops.

10 / 01: 1 NO / 1 NC for status indication and interlock.

11: 1NO+1NC for complex control logic such as automatic switching systems.

4.3 Capacitor Capacity Reference (@400V)

5. Accessories & Expansion Options

ABB UA series capacitor switching contactors cover full current range 16A~140A, providing standard type and RA built-in resistor type.

Flexible auxiliary contact configurations (00/10/01/11) and global compatible coil voltages are available.

The RA series effectively reduces switching inrush current, protects contacts and extends service life, making it the ideal solution for low-voltage reactive power compensation systems.