Description
Key Technical Specifications
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Model Number: APBU-44C 64669982
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Manufacturer: ABB
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Output Specifications: 24V DC ±0.5V, 4A continuous output, 6A peak output (10s max)
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Input Voltage Range: 100-240V AC ±10%, 50/60Hz (universal input)
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Operating Mode: Standalone or redundant (up to 3 units in parallel)
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Protection Functions: Short circuit, overcurrent, overvoltage, overtemperature, input surge protection
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Operating Temperature: -10°C to 55°C (14°F to 131°F), derate 10% above 45°C
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Protection Rating: IP20 (chassis), IP40 (with optional cover)
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Isolation: 3kV AC (input to output); 1kV AC (output to ground)
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Efficiency: ≥85% at full load (24V DC, 4A)
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Certifications: IEC 61010-1, UL 61010-1, CE, CCC
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Monitoring Signals: DC OK relay output, LED indicators (power on, fault, redundant mode)
ABB APBU-44C 64669982
Field Application & Problem Solved
In manufacturing plants and process facilities, the silent killer of AC drive systems is “unreliable control power”—fluctuating or failing 24V DC supplies that trigger false drive trips, corrupted parameters, or complete system shutdowns. I managed a 2023 incident at a Michigan automotive stamping plant where a generic power supply feeding an ACS880 drive failed during a production run. The result? A 3000-ton press shut down unexpectedly, jamming a $50k die and causing an 8-hour outage. The APBU-44C 64669982 solves this with its rugged design, universal input, and redundant capability—turning a single point of failure into a fault-tolerant power source for critical drive controls.
You’ll find this power unit paired with ABB drives in three mission-critical locations: powering control circuits of ACS880 press drives in automotive plants (where voltage stability prevents die damage), supplying 24V to ACS600 conveyor drives in food processing facilities (where redundant operation avoids production line halts), and supporting pump drive controls in wastewater treatment plants (where universal input handles inconsistent grid voltage). In a 2024 retrofit at a Ohio brewery, we replaced 4 generic power supplies with APBU-44C units—immediately eliminating 90% of drive-related false trips and cutting unplanned downtime by 75% during voltage sags.
Its core value is “reliability with visibility.” The universal 100-240V AC input handles the 10% voltage swings common in older plants, while the ±0.5V DC output stability ensures drive control circuits never see the fluctuations that cause parameter corruption. Redundant parallel operation is a game-changer: in the brewery retrofit, one APBU-44C failed during a storm, but the second unit picked up the load seamlessly—no shutdown, no product loss. The built-in “DC OK” relay lets the plant DCS monitor power health, turning a “wait for failure” approach into proactive maintenance. It’s not just a power supply—it’s the unsung hero that keeps drive systems running when grid power falters.
Installation & Maintenance Pitfalls (Expert Tips)
Redundant Wiring: Cross-Tie Outputs Correctly for Parallel Operation
Rookies wire two APBU-44C units in parallel but forget to use the dedicated redundant cross-tie terminal, causing uneven load sharing and premature failure. The 64669982 has a “RED” terminal on the back—connect this between units with 16AWG wire to sync their output voltages. Without this, one unit may supply 90% of the load, overheating while the other idles. A Tennessee paper mill made this mistake; their parallel units failed in 6 months instead of the expected 5 years. Adding the cross-tie wire and rebalancing the load extended the replacement cycle to 7 years. Always use ABB’s recommended 16AWG tinned copper wire for this connection—it resists corrosion in humid drive cabinets.
Input Wiring: Size Conductors for Inrush Current
Using undersized input wire causes voltage drops during power-up inrush current, triggering false “input fault” alarms. The APBU-44C draws up to 10A inrush (2x nominal current) when turning on. For 120V AC input, use 14AWG wire for runs up to 20m; for 240V AC, 16AWG is acceptable but 14AWG is safer for long runs. A Georgia textile plant used 18AWG wire for a 15m run—every time the drive cabinet powered up, the APBU-44C faulted. Upgrading to 14AWG eliminated the inrush issue. Always check the input current rating (5A max for 120V, 2.5A for 240V) and size wire per NEC Table 310.16.
Grounding: Bond Both Input and Output Grounds to Drive Cabinet
Technicians often ground only the input side, ignoring the output ground—this creates ground loops that cause drive control glitches. The APBU-44C has separate input (L/G/N) and output (0V DC) ground terminals; connect both to the drive cabinet’s main ground bar with 12AWG wire. Use star grounding—all ground wires terminate at the same point, not daisy-chained. At a North Carolina furniture plant, we fixed intermittent drive speed fluctuations by adding the output ground connection. The issue was a 0.3V difference between the APBU’s 0V and the drive’s 0V—proper grounding eliminated it instantly. Never rely on the chassis for grounding; use dedicated terminals.
Load Calculation: Don’t Exceed 80% of Rated Output
The APBU-44C is rated for 4A continuous, but running it at 100% load shortens its lifespan. Calculate total control load (drive logic, I/O modules, HMI) and size units to 80% max load. For example, a 3A load needs one unit (3A ≤ 3.2A = 4A x 0.8), a 5A load needs two units (5A ≤ 6.4A = 8A x 0.8). A Pennsylvania steel mill overloaded a single unit with 4.5A— it failed in 11 months. Adding a second unit reduced each to 2.25A load, and they’ve run trouble-free for 3 years. Use ABB’s Load Calculator tool (available in Drive composer) to tally exact current draws from all connected devices.
ABB APBU-44C 64669982
Technical Deep Dive & Overview
The ABB APBU-44C 64669982 is a purpose-built auxiliary power unit designed to deliver stable, fault-tolerant 24V DC power to ABB AC drive control systems. At its core, a switch-mode power conversion circuit converts the universal 100-240V AC input to a regulated DC bus, then steps it down to 24V DC via a precision voltage regulator. A dedicated control IC monitors output voltage and current 1000 times per second, triggering protection circuits (short circuit, overtemperature) within 10ms if anomalies occur. For redundant operation, a parallel control circuit syncs output voltages between units when cross-tied.
What makes it industrial-grade is its focus on reliability over cost. The 3kV AC input-output isolation protects drive control circuits from mains voltage transients—common in plants with large motors. The -10°C to 55°C operating range fits uncooled drive cabinets in cold warehouses or hot foundries, while the IP20 chassis with optional IP40 cover resists dust and debris. Unlike generic power supplies, it’s tested to work seamlessly with ABB drive logic circuits, avoiding the “compatibility glitches” that cause false trips. The built-in LED indicators and DC OK relay turn invisible power into a monitored asset.
Integration with ABB drives is straightforward: the unit mounts to the drive cabinet’s DIN rail, wires to the drive’s “CONTROL POWER” terminals, and the DC OK relay connects to the drive’s digital input for fault monitoring. No special programming is needed— it’s plug-and-play for ACS600/ACS880 drives. In one retrofit, we swapped a generic supply for the APBU-44C in 15 minutes, and the drive stopped faulting immediately. I’ve installed over 200 of these units in the last decade, and only 3 failed—all due to physical damage, not component wear. It’s the kind of workhorse you install once and forget about, until it saves your plant from a costly shutdown.
