Why Do We Use Belts?

It’s getting hot out, you turn on your AC, and everything works great for about an hour or two. Outside, your condenser reaches saturation, it’s cooling fan doesn’t budge, and soon the house is back to the sweltering mess it had been before. It’s unbearable, but there you are. Welcome to Summer, right? The Belt Drive There are a ton of applications where we need something to spin, whether it’s a fan, blower, or even the drum in a washing machine. We often use a belt to connect the blower and anything else back to a single motor. Eventually that belt gives out and needs to be replaced. This could be from simple wear and tear, rot, or even accidental damage, like running over a rope with a tractor, jamming up the mower deck blades, and then burning up the belt with friction. Belts offer a number of advantages though. They’re cheap to manufacturer, flexible, and can reduce the total number of parts a given machine needs. A belt can power multiple output devices, synchronize those output devices, and it frees up the designers to create different designs with fewer parts or more compact layouts than could otherwise be achieved. But WHY?! You could put the blower right on the motor! Belts also serve two other majorly attractive purposes in cutting down costs. A belt allows us to do gear reduction and it allows us to use some cheaper (but […]

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Why is There a Belt in the Furnace?

Is it weird that we use belt drives in furnaces? Belts aren’t necessarily known as the most durable or flame-resistant thing in the world. Why would we put a belt next to a roaring inferno? It’s 2018, why don’t we just bolt the motor straight to the fan, blower, or whatever it is we’re driving?   Gear Reduction Spinning blowers, fans, and other equipment requires a lot of mechanical power. At the same time, it can take more power to overcome the friction on a resting object, especially for heavier parts or equipment that’s not perfectly supported. There can be additional friction by such offset loads. Providing enough force to move this equipment requires bigger and bigger motors. Or does it? Physics is full of tricks. We can use a concept called Gear Reduction so that a smaller motor can get the job done. Instead of outputting a lot of power at once, we output less power, but more revolutions of the motor. For every 2 rotations of the motor, the blower might only spin once. This reduction requires the motor to spin faster to achieve the same result as a bigger motor, but it won’t need as much torque to do that work. The easiest way to see this concept in action is to look at a multi-speed bike. Your gears are different sizes to allow for different speeds. In low gear, it is incredibly easy to spin the […]

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