Description
Key Technical Specifications
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Model Number: SPAU140C
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Manufacturer: ABB
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Function: Synchro-check + voltage-check relay
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Voltage Input: 100/110/220 V AC, 3-phase, 0.4–36 kV via VT
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Frequency Range: 45–65 Hz (50/60 Hz)
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Phase Difference: 5–50° adjustable, 1° resolution
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Voltage Difference: 0.02–0.4×Un, 0.01×Un steps
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Frequency Difference: 0.02–0.5 Hz, 0.01 Hz steps
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Trip Time: <20 ms (synchro), <120 ms reset
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Outputs: 2 × Form-C relays, 5 A @ 250 V AC/DC
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Comm: RS-232/RS-485 (Modbus RTU)
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Power: 24 VDC or 48/110/220 V AC/DC module
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Temp: −20 °C to +60 °C; IP65 enclosure
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Dimensions: ~114 × 176 × 85 mm; 1.2 kg
ABB SPAU140C
Field Application & Problem Solved
In the field, the biggest headache is paralleling two feeds without frying the breaker. SPAU140C sits across both sides of the tie and won’t close unless voltage, phase, and frequency are inside your set window. You’ll typically find it on generator tie-breakers, bus-tie cells, or anywhere you need to bump two networks together without a bang. Its main value is speed—1 ms trip—so you can close under 0.2 Hz slip and not weld the contacts.
In the field, the biggest headache is paralleling two feeds without frying the breaker. SPAU140C sits across both sides of the tie and won’t close unless voltage, phase, and frequency are inside your set window. You’ll typically find it on generator tie-breakers, bus-tie cells, or anywhere you need to bump two networks together without a bang. Its main value is speed—1 ms trip—so you can close under 0.2 Hz slip and not weld the contacts.
Installation & Maintenance Pitfalls (Expert Tips)
VT ratio typo kills the relay – Enter the actual VT ratio in the menu. If you leave it at 1:1 on a 4 kV bus, the relay thinks 4 kV is 110 V and you’ll never get a “sync OK.”
Phase sequence matters – Swap A-B on one side and the relay sees 180° out-of-phase and locks out. Always phasor-check before first close.
Dead-time setting too short – If you set dead-time to 0.1 s on a motor bus, the relay will try to close while the motor is still spinning down. Use 5–10 s minimum on motor loads.
Relay output bounce – The Form-C contacts are good for 5 A but not for high-inductive break. Put a snubber across the coil or you’ll pit the contacts in six months.
ABB SPAU140C
Technical Deep Dive & Overview
SPAU140C is a numerical relay—no moving parts. It samples both sides, runs a DFT, and compares V, f, and φ every cycle. Inside is a 16-bit DSP, opto-isolated inputs, and dual relays. All settings live in EEPROM; no battery to change. Lose 24 V and the relay drops the output—tie it to the same UPS as the trip coil. Card keys itself into the SPACOM rack; don’t force it or you’ll break the plastic lock.
SPAU140C is a numerical relay—no moving parts. It samples both sides, runs a DFT, and compares V, f, and φ every cycle. Inside is a 16-bit DSP, opto-isolated inputs, and dual relays. All settings live in EEPROM; no battery to change. Lose 24 V and the relay drops the output—tie it to the same UPS as the trip coil. Card keys itself into the SPACOM rack; don’t force it or you’ll break the plastic lock.
