Contents
What type of load is a power supply?
Resistive loads are easy on a DC power supply. When you turn off the power, the current quickly drops to zero and no damage is done. Inductive loads are another matter. If you’re using a DC power supply to power DC motors, solenoids, fans, relays and other inductive loads, you need some kind of circuit protection.
What is the power factor of a desktop computer?
A standard power supply has a power factor of 0.70-0.75, and a power supply with PFC has a power factor of 0.95-0.99. PFC is not used solely for computer power supplies.
What is the difference between inductive and resistive loads?
In resistive loads, such as light bulbs, the voltage and current waves match, or the two are in phase. As you might guess from the name, resistive loads only resist the current and are the simplest type of load. In inductive loads, such as an electric motor, the voltage wave is ahead of the current wave.
Is a computer a resistive load?
They are a mostly resistive load in that the AC voltage is converted to DC, then is used to drive a switching power supply.
Can an inductive load damage a DC power supply?
If you’re using a DC power supply to power DC motors, solenoids, fans, relays and other inductive loads, you need some kind of circuit protection. Without this protection, your power supply can be damaged by high voltage spikes from these devices. Figure 1 shows an inductive load connected to a DC power supply.
What should be the voltage of an inductive load?
Ensure that the chosen components are suitably rated for the inductance and energy to be dissipated. The peak reverse voltage ratings should be a minimum of two times the power supply maximum output voltage. The continuous forward current ratings should be a minimum of 1.5 times the power supply maximum output current.
What happens when you turn off an inductive load?
When you turn off the power, the current quickly drops to zero and no damage is done. Inductive loads are another matter. If you’re using a DC power supply to power DC motors, solenoids, fans, relays and other inductive loads, you need some kind of circuit protection.
How can I protect my power supply from positive load?
Where positive load transients, such as back EMF from a motor might occur, or stored energy is present such as a battery, a second blocking diode in series with the output is recommended to protect the power supply. Ensure that the chosen components are suitably rated for the inductance and energy to be dissipated.