If you need to brake AC motors, it may be time to consider the DC injection braking method. Among other reasons, DC injection braking is effective, smooth, and reliable. Without the wear and tear of friction, DC injection is one of the top choices for machinery and aviation mechanics and technicians around the globe. In this article, Ambi-Tech will be sharing five of the top methods used to brake AC motors.
5 AC Motor Braking Methods
While AC motors are technically simpler in their construction compared to DC motors, they are more complex electrically. The added complexity allows for various braking methods to be applied to AC motors, unlike DC motors. Here are the top five braking methods used around the globe to slow and stop AC motors:
#1. Motor-Loss Braking Method
This method is also known as “inherent-loss braking” for some. This braking method utilizes the tendency of AC motor speed to follow the frequency of the applied power. If the internal losses in the motor are sufficient related to the kinetic energy, the motor will slow with the decreased applied frequency. Keep in mind that if the frequency of the motor is reduced faster than the motor can handle, the DC bus voltage will rise. A DC bus voltage that gets too high will shut down the motor, and it will coast to rest.
#2. Dynamic Braking Method
Similar to the method above, dynamic braking relies on energy dissipation. Many drives have a resistor and capacitor connected across the DC bus. As these components absorb and dissipate kinetic energy, it dynamically brakes the motor to slow or to rest. Advanced drives have a DC bus voltage regulator that modulates the energy flow through the resistor, which controls the deceleration rate.
#3. Full Regeneration Method
Full regeneration is different from dynamic braking in that it returns the energy to the AC line to slow the motor. As read above, dynamic braking absorbs and dissipates energy. Full regeneration “repurposes” energy. A full power unit and reverse polarity is required for this method to work.
#4. Mechanical Braking Method
Similar to brake pads on a bike, mechanical braking requires physical contact with the rotor to slow and stop it. This is an effective method, however, it does require increased maintenance due to the friction that wears on the pads over time. If you’re using mechanical braking, you may also supplement the method with something like DC injection braking, too.
#5. DC Injection Braking Method
Simply, DC injection braking is reversing the current inside the AC motor so that it slows and stops. When you need to effectively, smoothly, and reliably slow and stop motors, DC injection is a great option.
Ambi-Tech: 50-Plus Years of Electronic Stopping Power
After 50 years in the braking industry, Ambi-Tech understands what you need to stop your motors with electric motor brakes. Our DC injection brakes are top-tier, and we work with many industries and support their braking needs. Contact us to get a quote today!