Power Supplies (FAQ)
What is a PSU?
PSU stands for power supply unit. We refer to a power supply as a device that converts mains AC input to a DC output. A PSU can sometimes refer to the power supply within a PC, but this isn’t something we can offer.
What is an AC to DC Rectifier?
An AC to DC rectifier is a device that converts alternating current (AC) into direct current (DC). There are different types of rectifiers, including half-wave, full-wave, and bridge rectifiers, each with varying levels of efficiency and output smoothness, but is a key component within most power supplies.
This is why the teminology used typically refers to the finished product, which is a DC Power Supply. So whilst the rectifier refers to a component within a power supply, it is most commonly used to refer to the finished product, which is a DC Power Supply.
What is a DC Power Supply?
A DC Power Supply is a device that provides a steady Direct Current (DC) voltage to power electronic devices and systems. Unlike Alternating Current (AC), which alternates across 0Vdc, DC flows constantly which is why it is used for powering most consumer electronics and industrial loads.
DC power supplies typically convert AC from a wall outlet into regulated DC output, whereas DC/DC Converters adjust one DC voltage to another.
What is a Switch Mode Power Supply?
A switch mode power supply (SMPS) is a comparatively compact and efficient device that converts electrical power from AC to DC. Unlike traditional linear power supplies, SMPSs rapidly switch the input voltage on and off at high frequencies, and are able to achieve higher efficiency and reduced heat generation. It also allows the products to be smaller, lighter and cheaper than has historically possible. Most modern power supplies are Switch Mode, with linear power supplies mostly used for specialised applications.
What Power Supply do I need? How do I pick a Power Supply?
To answer this, you need two pieces of information, your required voltage and required power (either in Amps or Watts). First, find the DC voltage required. Some common voltages are 12Vdc and 24Vdc. It is important to select the correct voltage, and check it requires DC not AC power.
Next, find how much power is required. This is measured in amps or watts (with watts being the total power, calculated as Voltage x Amps), and you need to use a power supply with more power than your required load. So, if you have a 300W load the very minimum requirement is a 300W power supply. However, you can use a power supply with higher output power, for example a 350W power supply.
What size DC Power Supply do I need?
To determine the correct size of power supply, you must first consider the output voltage you require. For example, some standard voltages are 24Vdc, 48Vdc and 110Vdc.
Once you know the voltage, you need to know how much power you need. If you now the voltage you need to know either the:
- Output Current – The amount of amps your load needs.
- Output Wattage – The total output power, made using Voltage x Amps.
If you have any questions on which power supply you need, please contact us so we can assist.
Why do you use a DC Power Supply?
A DC Power Supply is used because many electronic devices and systems require direct current (DC) for proper operation. As Alternating Current is used for power distribution, most electronic devices will need a converter between AC and DC, such as via a power supply. DC Voltage is ideal for powering circuits, sensors, computers, motors, and other sensitive equipment that need stable DC voltages.
How do you use a DC Power Supply?
There are a few stages to using a DC power supply. First, you must connect the power supply to it’s mains voltage. Some power supplies require an IEC connector or plug, but industrial power supplies typically need to be wired into via terminals on the unit.
The next stage is to connect this to your load. Some power supplies use an output jack, but most we supply are wired into using it’s terminals. These are available in a number of form factors, from screw terminals to push fit connectors.
How do you power a DC power supply?
A DC power supply is powered by an AC input. To use this, connect the power supply to your AC source. Whilst most power supplies have a universal AC input, it is important to check the individual power supplies’ input before applying an AC input.
How do I know what power supply I need?
There are 2 main aspects that help you select a suitable power supply:
- Output Voltage: Check what the required output voltage for your load or device is. Some popular options are 12Vdc, 24Vdc and 48Vdc.
- Output Power Requirement: How much power does your load require. This is displayed as either wattage (W) or current (A). You need to select a power supply with a larger wattage and current than your required load.
- Mounting Style: With Chassis Mount, 19” rack mounting and DIN Rail mounting options available, it is important to check how you wish to install the unit.
- Communications and Features: With options with external control and communications, to power supplies for very specific applications, there are many features and solutions available. If you require a certain feature of use-case, contact us so we can advise further.
Can I use a Power Supply with lower amps?
No, if your minimum required load (A) is less than the maximum output current (measured in Amps), you will need to use a larger power supply. For example, a 10A power supply could be used to power a 5A load, but a 5A power supply could not power a 10A load.
Can I use a Power Supply with higher amps?
Yes, current is drawn, not forced. So you can use a 10A power supply to power a 5A load. The 10A power supply would only supply 5A, but still have the capability to power a further 5A.
What is a UPS Power Supply?
UPS refers to Uninterruptible Power Supply, which means the output will not be interrupted in a mains failure by using a battery backup. We offer UPS units with either a DC or AC output, and more information can be found on our DC UPS and AC UPS applications.
What is a 3-phase Power Supply?
When asked this question, we assume the user requires a power supply with a 3-phase input. These are available, but there aren’t as many options as possible available and they usually start at a higher wattage output. If this is required, please advise us on your requirement so this can be looked in to.
How do I choose a replacement power supply?
As with all electrical products, advancements and changes in specifications means older power supplies are no longer available. With 25 years of experience we’ve seen many changes across the industry, so if you need help finding a replacement we can help. With that in mind, there are a few things to note when looking for that replacement.
- Output Power and Voltage – Your old power supply will most likely tell you it’s output power and voltage, which will certainly help with sizing a replacement. If you know the actual power requirement of your load it will help with replacement.
- Mounting and physical size – Do you require the replacement to be mounted on DIN Rail, rack mount of chassis mount? There are many options available, and sometimes a picture of what you require will help.
- Features – Are there any features, such as output adjustments, specific certifications or communication requirements you have?
How do I figure out what charger I need?
Choosing a charger has similar requirements to choosing a power supply, but there are some further points to check. Some of the requirements you need to consider are:
- Output Voltage - Check what the required output voltage for your batteries is. Some popular nominal voltages are 12Vdc, 24Vdc and 48Vdc, which correlate to charging voltages such as 13.2Vdc.
- Power Requirement – How much power do you require to charge these batteries? Once you know this in Amps or Wattage, you can look for suitable solutions.
- Battery Type – Different batteries require different charging cycles. For example, Nicad and lead acid are suitable to charge with a float and boost voltage whereas lithium require stage charging.
What is DC OK on a power supply?
DC OK on a power supply indicates the status of the device. Typically this shows it is functioning properly and delivering the correct DC output voltage. This status is typically shown via an LED indicator or a signal relay output.
- If the DC OK light is on, it means the output voltage is stable and within the specified range.
- If the light is off or a signal is not active, it suggests an issue, such as a fault, overload, or a voltage outside the acceptable range.
This feature is useful for monitoring and troubleshooting, and is the first point to check if you are having issues with a power supply.
What does Vdc mean?
Vdc, sometimes written VDC, is an acronym for Voltage Direct Current. It shows us that the voltage either to or from a source is a direct current, rather than Vac which is Voltage Alternating Current.