Fan laws and fan curves are a deep subject with a lot of nuance and variation. Just to get our heads around the subject, let's focus on two different types of fans that we see all the time in HVAC: the prop/axial type and the radial/centrifugal type. Centrifugal/Radial As we increase the pressure differential across […]

Have you ever noticed that a blower motor rated for 120V draws about twice the amperage of the same horsepower motor rated at 240V? That is because motors are rated in watts or horsepower, and according to Watt's law, Watts = Volts x Amps. To keep the wattage output the same at 120V, it draws […]

Another follow-up article by Michael Housh… Enjoy! In this article, I thought I would show a pump curve and match it up with our system head-loss curve that we created in the last article, but before I do that, I thought I would talk a little bit more about the system head-loss curve and why […]