Power Supply Selection Guidelines
Keep the following requirements in mind when selecting your power supply.
- Power source, input voltage and Frequency (AC/DC)
- Number of DC devices to be powered
- Voltage requirements of DC devices
- Wattage/Amperage of each DC device required
- Maximum/Peak draw of each DC device
- Physical space available and mounting requirements
- Check for applicable safety approvals for the location and application
The conversion of Volts to Watts is governed by the equation Watts = Amps x Volts.
Note: there are 1000 milliamps (mA) in 1 amp.
While most power supplies allow operation at 100% of rated capacity, it is recommended that an extra 30% be factored in. This allows the power supply to run cooler, more efficient and extends the life.
Device #1 requires 24 Vdc and draws 1 Amp [24Vdc X 1A = 24 Watts]
Device #2 requires 24 Vdc and draws 500mA [24Vdc x (500/1000)A = 12 Watts]
Total wattage required is (24 + 12 watts) x 1.3 = 46.8 Watts
Round up to the nearest 10 watts would be 50 watts.
Therefore, you would select a power supply rated at 50 watts and outputs 24 volts DC.