Frequently Asked Questions about Using Switching Power Supplies
1. What should I pay attention to when choosing a switching power supply?
A: In order to increase the life of the switching power supply, it is recommended to select a model with 30% more output power rating. For example, if the system requires a 100W power supply, it is recommended to select a power supply with an output power greater than 130W, and so on to effectively increase the life of the power supply. It is also important to consider the operating temperature of the power supply and the availability of additional auxiliary cooling equipment, as the rated output of the power supply will be reduced at high ambient temperatures. Selection of functions according to application requirements: Protection functions: Over Voltage Protection (OVP), Over Temperature Protection (OTP), Over Load Protection (OLP), etc. Application functions: Signal function (POWER GOOD, POWER FAIL), remote control function, telemetry function, parallel connection function, etc. Special functions: power factor correction (PFC), uninterruptible power supply (UPS). Select the required safety and EMC certificates. 2.
2. Can POWER be used in 45~440Hz, if yes, is there any other impact?
Answer:Switching power supply can be used in this frequency range. However, if the frequency is too low, the efficiency will be reduced, for example: input voltage 230VAC and rated load, when the input AC frequency is 60Hz, the efficiency is 84%, but if the input AC frequency is reduced to 50Hz, the efficiency is 83.8%; and too high will make the PFC function of the model, the PF value decreases, and also cause an increase in leakage current, for example: voltage 230VAC, the PF value decreases, and also cause an increase in leakage current, for example: voltage 230VAC, the frequency is 60Hz, the PF value increases. When the input AC frequency is 60Hz, the power factor is 0.93 and the leakage current is 0.7mA; when the input AC frequency is 440Hz, the power factor drops to 0.75 and the leakage current increases to 4.3mA. 3.
3. If 24V is required, but the new model is not available, can I use 2 sets of 12V in series?
Answer:Yes, but please note that the *smallest current of the series-connected model is the *maximum current of the whole system after the series-connection. In addition, in order to prevent the power supply in series from causing damage to the internal capacitors during start-up, it is recommended to connect a diode in parallel with the output of the SPU.
4. If I need 600W power supply, can I use two 300W power supplies in parallel?
A: No, you can't connect them directly in parallel. Because generally 300W is not designed with parallel connection function, when the output voltage of two power supplies is different, the one with higher voltage will bear most or all of the loss, it is recommended to use the model with parallel connection function.
5 Measuring two output power supplies, +5V is correct, but +12V is out of specification, what is the reason?
Answer: High-tech products with multiple outputs (more than 2 groups) have the requirement of *small load, please refer to the manual before use. When 5V/4A, 12V/1A, 12V output voltage is high, about 12.8V has exceeded the book on the ± 6% (12.72V), at this time, 12V if you add 0.2A according to the instructions of the * small load, the 12V output voltage can be reduced to about 12.3V.
6 Why can't the power supply turn on smoothly if the load is a motor, light bulb or capacitive load?
A: When the load is a motor, light bulb or capacitive load, the current is too high at the moment of switching on the power supply, it is recommended to use a power supply whose overload protection method is a fixed-current design product.
7. Why does the power supply crash when in use, but can operate again after switching off and switching on again?
Answer: Generally caused by the use of power supplies in about two cases, first of all, the load may be instantaneous overload caused by overload protection, it is recommended to enhance the power supply output power or modify the design of the overload; ** is the temperature rise is too high, the occurrence of over-temperature protection phenomenon. All of the above situations will cause the power supply to enter a protective state and when the machine, and the situation is lifted and then turn on the machine can be restored to normal.
