Common issues with using a switching power supply
1. What precautions should be taken when selecting a switching power supply?
Answer: In order to increase the lifespan of the switching power supply, it is recommended to choose a model with an additional 30% 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, which can effectively improve the lifespan of the power supply. In addition, it is necessary to consider the working environment temperature of the power supply and the presence of additional auxiliary heat dissipation equipment. Under high ambient temperatures, the rated output of the power supply will decrease. Select various functions according to the application requirements: protection functions: overvoltage protection (OVP), overvoltage protection (OTP), overload protection (OLP), etc. Application functions: signal function (POWER GOOD, POWER FAIL), remote control function, telemetry function, parallel function, etc. Special functions: Power Factor Correction (PFC), No Power Cut (UPS). Select the required safety regulations and electromagnetic compatibility (EMC) certification to comply with.
2. May I ask if POWER can be used at 45-440Hz? If so, is there any other impact?
Answer: Switching power supplies can generally be used within this frequency range. However, if the frequency is too low, it will cause a decrease in efficiency. For example, when the input voltage is 230VAC and the rated load is 60Hz, the efficiency is 84%. However, if the input AC frequency is reduced to 50Hz, the efficiency is 83.8%; When it is too high, it will cause the PF value of models with PFC function to decrease, and also cause an increase in leakage current. For example, when the voltage is 230VAC and the rated load is rated, when the input AC frequency is 60Hz, the power factor is 0.93, and the leakage current is 0.7mA; When the frequency of the input AC is 440Hz, the power factor decreases to 0.75, while the leakage current increases to 4.3mA.
3. If a 24V voltage is required and the high-tech model does not have this, can two 12V series connection be used?
Answer: Yes, but please note that the small current in the series connection model is the large current required for the entire system after series connection. In addition, to prevent the possibility of internal capacitor damage caused by the connected power supply during startup, it is recommended to connect the SPU output end in parallel with a diode.
4. If a 600W power supply is required, can two 300W power supplies be used in parallel?
Answer: It is not allowed to directly connect in parallel. Due to the general design of 300W without parallel function, when the output voltage of two power sources is different, the high voltage will bear most or all of the losses. It is recommended to use a model with parallel function.
What is the reason for measuring two sets of output power supplies, where+5V is correct, but+12V exceeds the specification?
Answer: In high-tech products, there are multiple sets (more than 2 sets) of output models with * small load requirements. Please refer to the manual before use. When the voltage is 5V/4A and 12V/1A, the output voltage of 12V is relatively high, about 12.8V, which exceeds ± 6% (12.72V) of the reading. At this time, if a small load of 0.2A is added to 12V according to the instructions, the output voltage of 12V can be reduced to about 12.3V.
Why is the load caused by a motor, light bulb, or capacitive load that prevents the power supply from turning on smoothly?
Answer: When the load is a motor, light bulb, or capacitive load, the recommended overload protection method for the power supply is a product designed with constant current when the current is too high at the moment of startup.
7. Why does the power supply crash during use, and it can be operated again after being turned off and restarted?
Answer: There are generally two reasons for the power supply to crash during use. Firstly, it may be caused by instantaneous overload of the load, resulting in overload protection. It is recommended to increase the output power of the power supply or modify the overload design; If the temperature rise is too high, there may be a phenomenon of over temperature protection. All of the above situations will cause the power supply to crash due to entering a protected state, and after the condition is resolved, restarting can restore normal operation.
