The Downside of Skipping PWM
So, what happens if you completely ignore PWM? Well, depending on your application, you could face a whole host of problems. Let's explore a few of the potential pitfalls.
Firstly, youll likely have very limited control over motor speed. This can be problematic if you need precise or variable speed control. Imagine a robotic arm that can only move at one speed not very graceful, is it? Or a toy car that zooms at full speed into every wall.
Secondly, you could end up damaging your motor if you try to reduce its speed by simply lowering the voltage without PWM. This can lead to overheating and premature wear. Because the voltage drops, the motor may struggle to overcome static friction and other internal resistance, so it can get stuck on a lower current and create more heat.
Finally, efficiency is also impacted negatively when you simply try to lower the voltage without PWM. Simply put, you will waste a lot more energy generating heat instead of using that energy to move the motor.
Simply put, while using a DC motor without PWM is possible in some limited scenarios, the advantages of PWM are significant, more importantly it often saves you from doing something that can potentially damage your equipment.
2. Alternative DC Motor Control Techniques (That Still Often Use PWM!)
Okay, so PWM is generally the go-to method, but are there any other ways to control a DC motor? The answer is yes, though they often end up incorporating PWM in some form anyway!
Linear voltage regulators can be used to provide a lower voltage to the motor, effectively reducing its speed. However, as mentioned earlier, this method is significantly less efficient than PWM, as the excess voltage is dissipated as heat. It's like trying to stop a car by constantly riding the brakes you'll eventually wear them out!
Another technique involves using a variable resistor (potentiometer) in series with the motor. By adjusting the resistance, you can control the current flowing to the motor, thus affecting its speed. This method is simple but, again, quite inefficient, as the power dissipated by the resistor is wasted as heat.
Interestingly, even some seemingly different control schemes, like using microcontrollers to implement more sophisticated algorithms for motor control, often rely on PWM as the fundamental mechanism for adjusting the motor's speed. It's just a very effective and versatile method!
And while these alternative approaches might seem tempting in their simplicity, the efficiency and precision offered by PWM typically make it the preferred choice, especially in applications where power consumption and control accuracy are critical.
