How to choose switching power supply 24V output (peak load) & recommended models are released!


Which model should be selected from among the many 24V output switching power supplies?
In this article, for those who are considering switching power supplies for new device design, VAVE study, scrap power supply, etc., we will introduce in detail from how to choose without failure to recommended models by wattage.

New products of 24V output switching power supplies are released every year by many manufacturers, and it has become possible to select highly reliable power supplies with distinctive specifications.

However, it is a fact that many people are wondering which switching power supply to choose because there are too many models. Therefore, in this article, we will explain the points to pay attention to when purchasing a switching power supply with 24V output and the characteristics of the power supply by recommended manufacturer. Choose the manufacturer’s power supply that suits your needs.


24V output switching power supply is roughly divided into two types

Before checking how to choose a switching power supply with 24V output and recommended models for each wattage, let’s first understand the basic types of power supplies.

  • AC / DC converter
  • DC / DC converter

There are two main types depending on the input voltage. The input voltage of the AC / DC power supply is AC (alternating current), and the input voltage of the DC / DC converter is DC (direct current).

The AC / DC power supply is the power supply that converts the commercial AC power supply (AC) sent to each factory or home to a stable DC voltage (DC). On the other hand, a DC / DC converter is a power supply that converts a direct current power supply (DC) such as a battery into another stable direct current voltage (DC).

From here, we will explain each feature

What are the features of AC / DC power supply

The most sought after “AC / DC power supply” among switching power supplies is a 24V output power supply. Therefore, the number of models is abundant, and it is easy for users to find a power supply with the specifications they desire.

The input voltage is generally single-phase 100 / 200V and three-phase 200V.
The current value ranges from 0.2A (5W) to 100A (2400W) for single-phase 100 / 200V input and 40A (960W) to 75A (1800W) for three-phase 200V input.

There are various types such as single-phase 100 / 200V input type, board type, DIN rail type, onboard type, and power module. Three-phase 200V input is only partly DIN rail type and unit type.

What are the features of DC / DC converters

 A power supply whose input voltage and output voltage of the DC / DC converter are direct current voltage (DC).
The 24V output DC / DC converter in Thailand mounted on the board has a power module. The small onboard power supply and POL (Point of Load) have only 15V output.

Input voltages are generally DC48V, DC110V, and DC280V. DC48V is often used for communication systems, DC110V for power systems, and DC280V for FA robots. The capacity is about 50W to 500W.



Four points to check when selecting a switching power supply

After confirming the basic types of switching power supplies, we will show you how to choose a power supply that you will not regret. In order to identify the model that suits your needs, let’s master the selection method properly so that you can judge whether the power supply is good or bad. What I want to pay attention to when choosing such a power supply

  1. Ambient temperature and load factor
  2. Supports peak current
  3. Electrolytic capacitor life
  4. Other features

The above four points. From here, I will explain each point in more detail, so please refer to it when selecting.

Check the load factor (current) from the ambient temperature.

When choosing a power source, the current value is a very important point. It is wise to choose a power supply that matches the ambient temperature of the power supply in the device / equipment when choosing the optimum power supply, rather than “choose a 10A power supply because the required current is 10A”. The value varies greatly depending on the ambient temperature of the power supply.

Be sure to check the “Load factor for ambient temperature” table in the specifications.
In the table below, when the ambient temperature of the power supply is 50 ° C and it is used with standard mounting A, it can only be used at 70%. In other words, if the rated current is 10A, it will be 7A.




Furthermore, it is generally best to use it at a load factor of 70% to 80% of the rated current of the power supply. If it is 70% of 7A, it is better to use it at 4.9A. In other words, a 10A power supply will be used at 4.9A.

For motor load, select a power supply that supports peak current

The 24V output has a large motor load, requires torque at startup, and causes peak current to flow. If you select a power supply based on that peak current, you will end up with a large capacity (W) power supply.

A “peak current compatible” power supply can flow a peak current of 1.2 to 2 times the rated current for about 1 second at startup. This type of power supply has the great advantage of being able to use a small power supply and reducing costs.

If you are particular about reliability, read the calculated value of electrolytic capacitor life.

In addition to the load factor, if you select a switching power supply, you should carefully read the “calculated value of electrolytic capacitor life”. The larger the value, the longer the life and the more reliable switching power supply can be selected.

It is expressed in hours (H) or years depending on the manufacturer.
The life of the electrolytic capacitor is also determined by the ambient temperature and load factor. Generally, the ambient temperature is 40 ° C and the load factor is 80%, so the selection is made based on that condition.
Of course, check the life of the electric controller under the actual usage conditions for the ambient temperature and load factor.

In the past, the life of electrolytic capacitors was generally 4 or 5 years, but recent power supplies have become more efficient, and it is not uncommon for electric capacitors to have a life of 10 years or more. Some models have a life of 20 years or more, but the electrolytic capacitor has a sealing rubber and has an actual life of 15 years. Therefore, the maximum life of the electric controller should be about 15 years.

Also look at features

When choosing a new power supply, let’s look not only at the basic functions but also at other functionality. For example

  • Power factor improvement circuit
  • Harmonic current suppression
  • Noise terminal voltage class B

There are various functions that are provided depending on the model. It may not be necessary, but make sure that it is equipped with a “power factor improvement circuit”, is “compliant with harmonic current regulation”, and is compliant with “noise terminal voltage class B”.