In the section below, you can find the most frequently asked questions (and answers) we received.

These are categorized in Operation, Reliability, Compliance, and Others.

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When power supplies are connected in parallel, mostly, is intended to increase the output current. Due to the design of active current sharing, they are mostly without reverse current protection, therefore, they are not the best solution when talking about redundancy. For redundant purposes, please choose the PSU with redundant function or implement external redundant modules. Be sure that the difference in output voltage and wiring impedance, should be as small as possible.

1. Use PSP models as an example, connect P(LP/CS) terminals together (Please refer to the parallel function in the specification). Input and output should be connected in parallel before connecting to the AC source and loads. Shown as in the picture below (some specific power supplies require a minimum load after paralleling).

2. Output voltage difference between power supply units should be as small as possible, normally < 0.2V.

3. The power supplies should be paralleled with short and large diameter wiring together first, and then connected to the load.

4. After paralleling, the maximum usage of total power should be around 90% of the rated total power.

5. When the power supplies are paralleled, if the load is lower than 10% of the rated load of the individual power supply, the LED indicator or signals (Power Good, Pok, Alarm Signal) may malfunction.

6. To ensure that the load current is effectively shared in parallel operation, in general, it is recommended not to use more than 4-6 power supplies at one time. Please follow the maximum number of units as stated in the datasheet.

7. In some models, the +S, -S terminals should be used to reduce unstable pulsation of output voltage.

Categories: Industrial, Operation

Some power supplies provide a “Power Good” signal when they are turned on and send out a ” Power Fail” signal when they are turned off. This is usually used for monitoring and controlling purposes.

  • Power Good: after the output of a power supply reaches 90% rated voltage, a TTL signal (about 5V) will be sent out within the next 10-500ms.
  • Power Fail: before the output of a power supply is less than 90% rated voltage, the power-good signal will be turned off at least 1ms in advance.
Categories: Industrial, Medical, Operation

1. To increase the reliability of the power supply, we suggest users choose a unit that has a rating of 30% more power than actual need. For example, if the system needs a 100W source, we suggest that users choose a power supply with 130W of output power or more. By doing this, you can effectively boost the reliability of the power supply in your system.

2. We also need to consider about ambient temperature of the power supply and whether there is additional device for dissipating the heat. If the power supply is working in a high temperature environment, we need to make some derating to the output power. The derating curve of “ambient temperature” versus “output power” can be found on our specifications.

3. Choosing functions based on your application:

  • Protection function: Over Voltage Protection (OVP), Over Temperature Protection (OVP), Overload Protection (OLP), and etc.
  • Application function: Signaling Function (Power Good, Power Fail), Remote Control, Remote Sensing, and etc.
  • Special function: Power Factor Correction (PFC), Uninterruptible Power Supply (UPS) function.

4. Make sure that the model qualifies for the safety standards and EMC regulations you need.

Categories: Industrial, Medical, Others