1. Introduction
The purpose of this technical document is to validate and document the parallel operation of two Phoenix Contact QUINT4-PS/1AC/110DC/4 power supplies connected through a Micropower SSMDOR-11010 redundancy module. This configuration provides higher reliability and ensures continuous 110 V DC output to the load, even if one power supply fails.
Parallel connection is implemented to achieve:
- System redundancy, preventing total power loss from a single PSU failure.
- Load sharing between two identical power supplies.
2. Technical Background
2.1 Operating principle of QUINT4-PS in parallel
Phoenix Contact QUINT power supplies support parallel operation to share current and provide redundancy. When configured for parallel operation, the PSUs are set to the same voltage setpoint and drop characteristic, so they divide load current in a controlled manner. The QUINT POWER Software (see User Manual, Doc No. 107309_en_02, Section 6.1–6.2) provides the configuration interface (via NFC) and instructs enabling of “Parallel operation” and setting the voltage drop (recommended −0.5 V between no-load and nominal load) for optimum current distribution.
2.2 Redundancy module operation
The SSMDOR-11010 is a diode ORing redundancy module. Each PSU output is connected to an input channel of the module; the module isolates supply from each other to prevent backfeed and combines outputs to a single load terminal. The module introduces a forward voltage drop (typ. ≈ 0.6 V) which must be accounted for when computing load voltage.
Parallel operation requires both PSUs to:
- Have identical model numbers and voltage settings.
- Be adjusted via the QUINT POWER Software using NFC communication, ensuring matched voltage and dynamic behaviour.
- Feed into a redundancy module (e.g., SSMDOR-11010) to isolate each PSU and eliminate single-point failure risk.
3. Functional Explanation
- Each QUINT PSU converts 110 V.
- AC input into 110 V DC output.
- In parallel mode, both units operate at identical voltage levels; each contributes half of the total load current.
- The redundancy module uses diode-based isolation to ensure that if one PSU fails or is disconnected, the other instantly maintains output to the load without interruption.
- Configuration data (e.g., voltage setpoint, and parallel setting) is stored in the PSU’s non-volatile memory (EEPROM), as confirmed by Phoenix’s QUINT POWER software documentation.
4. Software configuration
- Power up PSUs (no load connected).
- Open QUINT POWER Software and place the NFC head on PSU1.
- Read device parameters → Set output voltage to 110.00 V (if adjustable).
- Enable Parallel operation checkbox in settings.
- Set voltage drop/compensation parameter to −0.5 V.
- Write/save the settings to PSU1. Repeat for PSU2.
- Confirm saved parameters by reading back configuration on each unit.
5. Test Cases and Observations
PSUs at No Load condition:
- T1 – Power supply 1
- T2 – Power supply 2
- T3 – Redundancy module
CASE: 1
| S.NO | Mode of operation | Voltage (V) | Current (mA) | ||||
|---|---|---|---|---|---|---|---|
| T1 | T2 | T1 | T2 | T1 | T2 | T3 | |
| 1 | PARALLEL | PARALLEL | 110.2 | 110.2 | 15.86 | 15.53 | 2.41 |
Note: At same voltage, if both power supplies are in parallel operation Condition with 2.41mA load.
CASE: 2
| S.NO | Mode of operation | Voltage (V) | Current (mA) | ||||
|---|---|---|---|---|---|---|---|
| T1 | T2 | T1 | T2 | T1 | T2 | T3 | |
| 1 | PARALLEL | PARALLEL | 110.8 | 110.2 | 20.31 | 10.95 | 2.43 |
Note: At different voltage, if both power supplies are in parallel operation Condition.
CASE: 3
| S.NO | Mode of operation | Voltage (V) | Current (mA) | ||||
|---|---|---|---|---|---|---|---|
| T1 | T2 | T1 | T2 | T1 | T2 | T3 | |
| 1 | SINGLE | SINGLE | 110.8 | 110.2 | 15.15 | 16.25 | 2.43 |
Note: At different voltage, if both power supplies are in single operation Condition.
CASE: 4
| S.NO | Mode of operation | Voltage (V) | Current (mA) | ||||
|---|---|---|---|---|---|---|---|
| T1 | T2 | T1 | T2 | T1 | T2 | T3 | |
| 1 | SINGLE | SINGLE | 110.2 | 110.2 | 15.70 | 15.22 | 2.41 |
Note: At same voltage, if both power supplies are in single operation Condition.
CASE: 5
| S.NO | Mode of operation | Voltage (V) | Current (mA) | ||||
|---|---|---|---|---|---|---|---|
| T1 | T2 | T1 | T2 | T1 | T2 | T3 | |
| 1 | SINGLE | PARALLEL | 110.2 | 110.2 | 18.57 | 12.32 | 2.41 |
Note: At same voltage, if one power supply in parallel and another in single operation Condition.
CASE: 6
| S.NO | Mode of operation | Voltage (V) | Current (mA) | ||||
|---|---|---|---|---|---|---|---|
| T1 | T2 | T1 | T2 | T1 | T2 | T3 | |
| 1 | PARALLEL | SINGLE | 110.2 | 110.2 | 15.78 | 15.36 | 2.41 |
Note: At same voltage, if one power supply in parallel and another in single operation Condition.
6. Conclusion
These test cases were conducted under no-load conditions to verify voltage stability and current behaviour of the dual QUINT4-PS/1AC/110DC/4 power supplies with the SSMDOR-11010 redundancy module. Both PSUs maintained consistent 110 V DC output with proper voltage matching and isolation. The redundancy module functioned correctly, confirming system readiness for parallel operation and fault-tolerant performance even without load applied.
7. References
- Phoenix Contact QUINT POWER Software User Manual – Doc No. 107309_en_02
- Phoenix Contact QUINT4-PS/1AC/110DC/4 – Datasheet (2904613)
- Micropower SSMDOR-11010 Redundancy Module – Datasheet