ABB SPAU140C Synchro-Check Relay

Description

Key Technical Specifications

• Manufacturer: ABB
• Model: SPAU140C
• Product Type: Synchro-check relay
• Series: SPACOM family
• Application: Checks closing conditions of two separate circuit breakers
• Protection Functions: Synchro-check and voltage-check stages
• Energizing Inputs: 100 V or 110 V
• Auxiliary / Control Input Range: 18-265 V DC or 80-265 V AC
• Output Contacts: 250 V AC/DC rated, heavy-duty and signaling contacts
• Communication: SPA bus / serial interface, 4,800 or 9,600 Bd
• Dimensions: 140 x 140 x 60 mm
• Weight: 0.8 kg

Product Introduction

ABB SPAU140C is a SPACOM synchro-check relay used to verify safe closing conditions before paralleling two systems or circuit breakers. ABB describes it as a relay with synchro-check and voltage-check functions, intended for coordinated switching in substation and industrial power systems.

This unit is a legacy protection device, so the real risk is not the relay itself but the settings, PT wiring, and breaker logic around it. In field work, I would verify the exact voltage class, terminal wiring, and bus communications before replacement, because a mismatch here can block closing or allow an unsafe close permissive.

SPAU140C

SPAU140C

Installation & Configuration Guide

Stage 1: Pre-Installation Preparation

1. Notify operations and create downtime. Verify the system is de-energized, apply lockout/tagout, and wait for discharge where applicable.
2. Gather an ESD strap, PH1 screwdriver, multimeter, wire labels, and a smartphone for photos.
3. Record CT/PT wiring, breaker control wiring, synchro settings, and every front-panel value before removal.
4. Photograph the relay front, terminal layout, and any jumper or selector positions.

Stage 2: Removing the Old Module

1. Remove the panel cover or relay bezel.
2. Label all wires before disconnecting them. Do not pull on PT or control wiring.
3. Release the mounting hardware and remove the relay carefully.
4. Inspect terminals, the panel cutout, and wiring for heat damage, corrosion, or loose connections.
5. Keep the old relay until the new one is fully tested and the breaker logic is stable.

Stage 3: Installing the New Module

1. Put on the ESD strap and verify the exact model match.
2. Copy every setting from the reference photos. That includes synchro thresholds, voltage-check values, time delays, and any blocking logic.
3. Mount the relay securely and confirm the panel cutout fits correctly.
4. Reconnect PTs, control wiring, and auxiliary supply with correct polarity and tight terminals.
5. Check off the install list: [] Settings matched, [] Wiring secure, [] Mounting locked.

Stage 4: Power-On & Testing

1. Use a multimeter to verify auxiliary supply and check wiring before energizing.
2. Power the relay and confirm display, LEDs, and self-supervision status.
3. Verify synchro-check operation with controlled test conditions or secondary injection.
4. Confirm close permissive, voltage-check, and alarm behavior.
5. Return the system to service only after functional tests pass.
6. If the relay blocks closing, check PT polarity, voltage selection, and setting mismatch first.

Frequently Asked Questions

Can I hot-swap the SPAU140C?
No. This is a protection relay tied to breaker logic, and live removal is not a field-safe practice. De-energize first.

Is SPAU140C obsolete?
Yes, it is a legacy ABB SPACOM relay. Stock is typically limited, so exact-type matching matters.

What does the relay do?
It checks synchro conditions and voltage conditions before two systems or breakers are connected. ABB lists it as a synchro-check relay with voltage-check functions.

Will my settings survive a replacement?
Not automatically. You need to record thresholds, delays, PT ratios, and any external blocking logic before removal.

Is this a direct replacement for other SPAU 140 variants?
Not always. The SPAU 140 family has variant-specific wiring and settings, so the suffix matters. Verify the exact model before ordering.

What condition is it usually sold in?
Commercial stock is typically New Original or New Surplus. If someone offers refurbished stock, ask for test records and return terms.

Why is the price lower than ABB list price?
Because surplus inventory usually trades below OEM pricing. That lower price only makes sense if the relay is the correct variant, tested, and backed by a real warranty.