PHOENIX 2904371 DIN Rail Switching Power Supply

Full Order Code: UNO-PS/2AC/24DC/90W/C2LPS

Phoenix Contact UNO POWER Series 2-Phase Input DIN Rail Power Supply

✅ Key Specifications

Input: 2-phase AC 400~500 V AC (Wide range: 264–575 V AC)

Output: 24 V DC, rated current 3.75 A, 90 W

Adjustable output voltage: 24~28 V DC (via potentiometer)

Output ripple: ＜50 mVpp

Overvoltage protection (OVP): ≤35 V DC

No-load power consumption: ＜0.7 W

Power factor cosφ: 0.48

Protection class: IP20

Mounting: NS35 DIN rail

Operating temperature: -25℃ ~ +70℃; derating 2.5% per Kelvin above 55℃

Terminals: Screw-type clamping terminals

C2LPS = NEC Class 2 output certification + hazardous area approval (Class I, Division 2, T4). The output circuit can be wired per Class 2 requirements without extra isolation or protective sheathing, suitable for powering PLCs, sensors and valve islands in explosion-proof cabinets.

No parallel or series connection allowed

✅ Typical Applications

Control cabinets with 400V two-phase power supply, hazardous locations, construction machinery, HVAC, wind turbine auxiliary control systems; power supply for PLCs, proximity switches, solenoid valves and HMIs.

Important distinction: Unlike conventional single-phase 220V UNO power supplies, this model is a high-voltage two-phase input version, which is frequently misselected on site.

✅ Replacement Reference

Single-phase counterpart in the same series: 2902994 (UNO-PS/1AC/24DC/90W/C2LPS), input range 85–264 V AC. Do not interchange the two models.

For higher power with the same structure: UNO 150W & 240W two-phase variants.

✅ Troubleshooting Guide

1. DC OK indicator off: First verify two-phase input voltage. The unit will not start under phase loss or input voltage below 264 V AC.
2. Excessive voltage drop under load: Check for overcurrent or temperature-induced derating.
3. Frequent protection trips: Load short circuit or output earth fault. Class 2 models feature highly sensitive short-circuit protection.

PHOENIX 2904371 (UNO-PS/2AC/24DC/90W/C2LPS) Installation Manual

Safety Precondition: Indoor cabinet mounting only, IP20 rating. C2LPS stands for Class 2 output plus Class I Division 2 hazardous area certification. All installation in explosive environments must comply strictly with ISA-12.12.01 standards.

1. Product Overview

Order No.: 2904371

Series: UNO POWER 2-phase DIN rail power supply

Input: 2-phase AC 264–575 V (400V two-phase, NOT single-phase 220V)

Output: 24 V DC, 3.75 A / 90 W, adjustable 24–28 V

Mounting: NS35 DIN rail (EN60715), horizontal installation

Housing width: 55 mm

2. Clearance Requirements (Mandatory for Heat Dissipation)

Side-by-side horizontal installation: 0 mm minimum clearance (units may be mounted tightly together)

Vertical stacking: Minimum 30 mm upper and lower clearance for cooling air flow

No upside-down or side mounting; only horizontal installation with terminals facing forward/downward

Do not install adjacent to heat-generating components (contactors, braking resistors); high ambient temperature will trigger power derating

Altitude derating: Power rating and insulation voltage must be reduced above 2000 m elevation

3. DIN Rail Installation & Removal
4. Hook the top latch onto the NS35 rail first
5. Press down the unit until the latch clicks securely into place
6. Removal: Insert a flat screwdriver into the bottom latch tab, pry upward to release the lock and pull the unit off the rail

Vibration resistance: Compliant with industrial cabinet vibration standards; no extra locking screws required once clipped firmly.

4. Wiring Specifications (M3 Screw Terminals)

Terminal type: Screw clamping terminals

Conductor size: Solid wire 0.2–2.5 mm²; stranded wire 0.2–2.5 mm²; AWG24～AWG14

Strip length: 8 mm

Cable temperature rating: ≥75℃ for ambient <55℃; ≥90℃ for 55~70℃ ambient

Tightening torque: 0.5–0.7 Nm (avoid over-tightening to prevent thread damage)

Terminal Definition (Critical: Two-phase input, no neutral N!)

Input terminals: L1, L2 (two-phase 400V AC, neutral N is not connected); PE protective earth terminal

Output terminals: +24 V, 0 V (24 V DC)

Adjustment potentiometer: ADJ (24~28 V fine-tuning; factory preset to 24 V)

Indicator: DC OK (green light ON = normal output; OFF = no output or protection active)

⚠️ Critical Warning: This is a 2-phase AC power supply. Never wire it as a single-phase L+N unit; incorrect wiring will cause failure or permanent damage.

5. Wiring Sequence (Lockout-Tagout Safety Procedure)
6. Confirm upstream circuit is de-energized and apply lockout-tagout
7. Connect PE protective earth first (reliable earthing is mandatory)
8. Wire the two-phase input lines L1/L2
9. Terminate the 24V DC load cables
10. Inspect for short circuits and earth insulation; confirm no shorted load circuits
11. Apply power and verify the DC OK green LED illuminates; trim the ADJ potentiometer to set target output voltage
12. Class 2 (C2LPS) wiring rule: Output cabling shall follow NEC Class 2 specifications; no shared trunking with high-voltage power cables without isolation barriers.
13. Protection Functions & Fault Diagnosis

Short-circuit protection: Constant current limiting. Class 2 versions feature high sensitivity; short-circuit triggers immediate shutdown, auto-recovery after fault removal.

Overload protection: Current exceeding 105% rated value activates current limiting

Overvoltage protection (OVP): Output shuts down above 35 V DC

Thermal protection: Over-temperature shutdown; auto-restart after cooling down

Undervoltage / phase loss: No start-up if input voltage drops below 264 V AC; DC OK light remains off.

7. Environmental & Installation Restrictions

Operating temperature: -25℃ ~ +70℃; 2.5%/K power derating above 55℃

Humidity: 5%~95% non-condensing

Forbidden applications: Outdoor direct mounting, dusty/corrosive atmospheres, water splash exposure

Explosion-proof installation (Class I Div.2 T4): Cabinet-only mounting; external wiring must not create ignition sources, comply with flameproof/enclosure standards.

8. Parallel & Series Connection

❌ This model does NOT support parallel current expansion or series voltage boosting. Select the QUINT series if multi-unit parallel operation is required.

9. EMC & Earthing

The PE terminal must connect securely to cabinet protective earth; floating earth is prohibited

Upstream overcurrent protection recommendation: C-curve MCB, 1 A or 2 A (for 400V two-phase circuit)

Class 2 output circuits normally do not require additional fuses; if required, implement UL1310 Class 2 current-limiting designs.

10. Commissioning Checklist

Unit fully clipped onto DIN rail with no play

PE earth connection solid and reliable

L1/L2 two-phase input voltage stays within 264–575 V AC

No short circuit or earth fault on output wiring

DC OK green LED stays steady ON after power-up

Measured output voltage matches the set value

30 mm vertical cooling clearance is maintained top and bottom

III. UNO-PS Full Model List

3.1 UNO-PS / 1AC Single-phase Standard Models (24V Output)

3.2 Other Output Voltages (12V / 15V / 48V)

1. UNO-PS/2AC Two-phase Standard Models (Non-C2LPS, No Class 2 Explosion Protection)

1. Model Naming Rule (For Selection Reference)

UNO-PS / 1AC/2AC / 24DC / 90W / C2LPS

1. 1AC = Single-phase input; 2AC = Two-phase 400V input (L1+L2, no neutral N)
2. 24DC = 24 V DC output
3. 90W = Nominal output power
4. C2LPS = Class 2 output + Class I Division 2 hazardous area certification (only available for the 90W model)
5. Supplementary Notes
6. Only two C2LPS explosion-proof models are available:

Single-phase: 2902994

Two-phase: 2904371 (your model). No higher-power two-phase C2LPS variants exist.

2. No parallel current expansion for the entire UNO series. Use the QUINT series if parallel operation is required.
3. All units come with screw terminals (SC). The second-generation UNO models use push-in PT terminals and are not mechanically interchangeable with this housing.