Schneider 140CPS11420 | Modicon Quantum AC Power Supply Module

Description

Key Technical Specifications

Product Introduction

When a Quantum rack loses its 5 V backplane rail, the whole chassis can go dark — CPUs drop, I/O stops scanning, and fault history often points straight back to the power supply. The Schneider 140CPS11420 sits in that exact spot: a Modicon Quantum AC power module that converts 115 V AC or 230 V AC line power into the 5.1 V DC rail used by the backplane and installed modules.

Its practical value comes from the output rating and installation flexibility. In a summable configuration, it can deliver 20 A at 60 °C; in a standalone configuration, the same module is rated for 11 A at 60 °C. That distinction matters during chassis design and spare-part replacement, because a 140CPS11420 is not automatically interchangeable with every other Quantum AC supply — the chassis loading, redundancy requirements, and output-current budget all have to match.

Schneider 140CPS11420

QA/QC Transparency SOP

1. Intake & Origin Verification
Check the nameplate for 140CPS11420, serial number, date code, voltage markings, and Schneider/Modicon branding. Confirm the module matches a Quantum chassis form factor. Reject units with missing labels, burnt connectors, cracked housings, or signs of liquid damage.

2. Live Functional Testing
Install the module in a known-good Quantum chassis or compatible test rack. Apply the correct AC input — 115 V AC or 230 V AC — and verify that the PWR OK LED illuminates. Confirm the backplane 5.1 V rail comes up cleanly and that the CPU or other modules do not repeatedly reset.

3. Electrical Parameter Tests
Measure input current at 115 V AC and 230 V AC. Verify output voltage is close to 5.1 V DC under load. Check input terminals, output terminals, and chassis contacts for shorts, abnormal resistance, or insulation degradation. Use a slow-blow 2 A fuse rating as the reference for upstream protection.

4. Firmware/Config Verification
This is a power supply module, not a CPU, so there is no application program to back up. Still, record the hardware revision, serial number, date code, and any alarm-contact behavior. If the chassis reports a power-supply fault, capture the exact fault text before clearing it.

5. Final QC & Anti-Static Packaging
Label the unit with test status, serial number, and any limitations. Package in anti-static material, protect the backplane connector, and block the AC input terminals from physical damage. A power module can look fine on the bench and still fail under chassis heat — so operating-temperature context matters.

Field Engineer Gotchas

Mixing 140CPS11420 with other Quantum AC supplies
Risk: The part number looks similar to other 140CPS modules, so it gets installed without checking output rating or configuration.
Solution: Confirm the exact model, input voltage range, and whether the application requires summable or standalone operation.
Blunt warning: “Quantum AC power supply” is not enough. The current rating and chassis behavior can differ.

Ignoring the 20 A summable vs. 11 A standalone difference
Risk: The module powers up, but the chassis faults under load.
Solution: Calculate the actual 5 V backplane load before installation. If the chassis is heavily loaded, a standalone-rated installation may not be enough.
This is the kind of mistake that passes a bench test and fails in the cabinet.

Wrong AC input voltage
Risk: 230 V AC is applied to a circuit wired or protected for 115 V AC, or vice versa.
Solution: Verify the facility supply, upstream breaker, and module input rating.
Use a 2 A slow-blow fuse as the reference protection rating.

Alarm contact wired as if it were a power output
Risk: The NC alarm contact is miswired, so the panel thinks the supply is faulty — or the fault is never reported.
Solution: Treat the alarm as a 1 NC, 6 A, 220 V fault-indication contact, not a power source.
Verify wiring against the panel schematic before energizing.

Thermal derating at 60 °C
Risk: The module is installed in a hot enclosure with poor airflow.
Solution: Confirm enclosure ventilation, ambient temperature, and chassis loading.
At 60 °C, the rated output depends on summable vs. standalone configuration. If the cabinet runs hot, assume nothing.

Schneider 140CPS11420

Application Scenarios

Modicon Quantum PLC main chassis power
A process control cabinet uses a Quantum CPU, I/O modules, and communication modules. The 140CPS11420 provides the 5.1 V DC backplane rail from a 115 V AC or 230 V AC source.

Water/wastewater pump station PLC replacement
A failed power supply takes down a remote PLC rack. The replacement must match the Quantum chassis, AC input voltage, and 5 V load — not just the physical slot size.

Manufacturing line control cabinet refurbishment
Older Quantum racks in packaging, bottling, or assembly lines may still rely on 140CPS11420 modules. Surplus replacements can work, but only if the chassis loading and ambient temperature are verified.

Rail, transit, or infrastructure BAS cabinets
Building automation and transit control cabinets sometimes use Modicon Quantum hardware for I/O, interlocking, or monitoring. A power-supply failure can disable an entire local control rack.

Anonymized case study
A water-treatment PLC rack lost communication after a brief power disturbance. The HMI showed no CPU fault, but all I/O went stale. The technician initially blamed the CPU. After checking the chassis LEDs, the real issue was the AC power supply: the PWR OK LED was off, and the 5 V backplane rail had collapsed. The failed module was a 140CPS11420. The replacement was installed only after confirming the AC input voltage, the 2 A slow-blow upstream fuse, and the total 5 V load. Once the correct supply was seated and the alarm contact was rewired to match the panel schematic, the rack came back online. The lesson: when a whole Quantum chassis dies at once, check the power supply before swapping CPUs.

FAQ

Is 140CPS11420 a 24 V DC power supply?
No. It is an AC input power supply for Modicon Quantum, accepting 115 V AC or 230 V AC. Its main regulated output is 5.1 V DC.

What is the output current rating?
It is rated for 20 A at 60 °C in summable configuration and 11 A at 60 °C in standalone configuration. The correct number depends on how the module is applied in the chassis.

Can I use 140CPS11420 instead of another Quantum AC power supply?
Not automatically. You must check input voltage, output current rating, summable/standalone mode, chassis loading, and alarm-contact wiring. Physical fit does not guarantee electrical compatibility.

Does this module have a fault alarm contact?
Yes. It has a 1 NC alarm output, rated at 6 A / 220 V, used to indicate a power-supply fault.

What fuse should be used upstream?
The associated fuse rating is 2 A slow-blow. Verify the actual panel protection against the site electrical design before installation.

Will this work in a redundant power configuration?
The 140CPS11420 is listed as summable or standalone. If the application specifically requires a redundant Quantum power architecture, confirm whether this exact module supports the required redundancy scheme before ordering.

Is this module still supported?
Treat it as a legacy Modicon Quantum spare. Availability is typically surplus or aftermarket. For new installations, confirm current Schneider Electric product status and replacement guidance before specifying it.