Description
Mitsubishi A1S61PN | AnS Series Power Supply Module, New Surplus
Architect’s Product Breakdown
The Mitsubishi A1S61PN operates as a heavy-duty switch-mode power supply engineered specifically for the MELSEC-AnS compact modular PLC series. Its primary responsibility is converting standard industrial line voltage (100–240 VAC) into tightly regulated low-voltage rails: a 5 VDC primary logic bus for the CPU and backplane modules, and an auxiliary 24 VDC output for loop or sensor power. Maintaining stable voltage output under dynamic load shifts is critical for preventing unexpected PLC watchdog faults and memory retention loss.
Deploying or replacing this unit requires strict verification of input wiring and cabinet grounding. Maintenance engineers must ensure that AC line feeds are free of severe transient spikes and that the terminal block screws are torqued correctly to prevent high-resistance micro-arcing. Adequate vertical spacing around the rack is also vital, as natural convection cooling prevents premature thermal stress on internal electrolytic capacitors.
A1S61PN
Key Technical Specifications
| Parameter | Specification |
| Manufacturer | Mitsubishi Electric |
| Part Number / Model | A1S61PN |
| Product Family | MELSEC-AnS Series PLC Automation |
| Input Voltage Range | 100 to 240 VAC (85 to 264 VAC max) |
| Input Frequency | 50/60 Hz (±5%) |
| Output Rails | 5 VDC (3.0 A) / 24 VDC (0.4 A) |
| Mounting Type | MELSEC-AnS Base Unit Slot (Leftmost position) |
| Operating Temperature | 0°C to +55°C |
| Storage Temperature | -20°C to +75°C |
| Relative Humidity | 10% to 90% non-condensing |
Field Engineer’s Pitfall Guide (Unique Value)
- Terminal Block Torque Neglect: Loose AC input screw terminals create high-resistance micro-arcs, leading to thermal degradation, voltage sag, and random PLC reboots during plant operation.
- Shelf-Aging of Bulk Capacitors: Power supplies sitting unpowered in warehouse inventory for years can experience dielectric breakdown when slammed with full line voltage. Use a variable AC source to ramp voltage if the unit has been stored long-term.
- Slot Positioning Errors: The A1S61PN must be mounted directly into the designated power supply slot on the left side of the AnS base unit. Forcing it into standard I/O module slots will result in complete backplane failure or equipment damage.
QA & Testing SOP (Transparency)
- Visual & Origin Verification: Units undergo microscopic inspection for authentic Mitsubishi laser markings, terminal block cleanliness, and the total absence of component scorching or leakage.
- Test Bench Simulation: The power supply is mounted onto a live MELSEC test rack, operating continuously under simulated maximum I/O and processor load to verify thermal stability.
- Ripple & Voltage Regulation Checks: Oscilloscopes monitor output ripple and voltage rail rigidity under dynamic load steps to ensure performance stays well within factory specifications.
- Anti-Static Packaging: Post-testing, units are secured in heavy-duty static-dissipative materials and packed with high-density cushioning to prevent transit damage.
Technical FAQ
- Can I hot-swap this power supply while the PLC rack is energized? No. Always de-energize and lock out the main AC input supply before extracting or wiring this module to prevent severe electrical arcing and backplane damage.
- What indicates an internal failure on this unit? Total loss of the RUN indicator LED, collapse of output DC voltage rails, or an immediate tripping of the upstream input circuit protection.
- Does this power supply require an external cooling fan? It relies entirely on natural convection cooling, making proper vertical cabinet spacing and louver maintenance essential.
- What warranty is provided with a surplus unit? Units carry a standard 12-month replacement warranty backed by full-load bench verification testing.
