Retrofitting of Power Supply with Redundancy

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A Tricky Problem

One of our customers in the system-integrating industry was awarded a retrofitting job for safety shutdown package. However, the existing infrastructure in their plant has been functional for over 10 years and hence they faced a challenge to propose an equally efficient solution to act as a power source. This is critical to the end user as this would ensure the functionality of all devices in the control cabinet. We were briefed in detail of the project requirements.

System Requirements:

    • Full redundancy of AC UPS & DC UPS
    • Load current: 45A for both AC & DC power
    • Auto current balancing

The main problem faced by our customer was the need of a DC/DC converter which could output a current of 45A. Another obstacle faced was the absence of auto current balancing products, which were not supplied by many manufacturers.

Exisitng wiring diagram for redundant power supply

Fig 1: Diagram of existing wiring installation

Devising a Solution

With Quint power supply’s Power Boost feature, the customer was able to achieve a maximum current of 25A. However, by connecting two 20A DC/DC converter units in parallel, the customer was able to yield a greater maximum output current of 50A. By adding a Quint-ORING Redundancy Module, we also dealt with the lack of auto current balancing. The load current would automatically be equally distributed by the Quint-ORING Module. With permanent redundancy monitoring of the input voltage, output current and decoupling section, the loss of redundancy would be reported before the entire system shuts down.

Proposed Design:

  1. Quint 40A Power Supply
  2. Quint 20A DC/DC Converter Unit x 2
  3. Quint-ORING Redundancy Module 24DC (2×20/1×40) unit x 1
  4. Quint-ORING Redundancy Module 24DC (2×40/1×80) unit x 2
proposal drawing for Phoenix Contact's redundant power supply solution

Fig 2: Proposed Design

Control cabinet with Phoenix Contact's redundant power supply solution

Fig 3: Control Cabinet

After several rounds of discussion and clarification of the technical aspects, our proposal was accepted by the customer. To achieve even distribution of current, we recommend the following:

  1. All power supply units connected in parallel must be set to the same output voltage
  2. All cables should have the same length and cross-sectional area

If you require any technical advice on your current project, feel free to contact us. We can be your trusted partner to provide creative solutions to fit your needs!



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