Application Note: Going from DC Motors to a Synchronized System of AC Motors and Drives

Overview:  At one company, there is what they call a brine box. There is a saltwater tank setup that slows an electric motor saw. Within this setup, they use three DC motors. They decided they would like to change the DC motors to AC motors. In addition to changing from DC to AC, they would like to implement speed control between the motors, including the ability to decelerate the motors at the same time and at the same rate.

The Solution: We selected the AC motors to match the required speed and torque needed for the application. This information was obtained by analyzing the load conditions and from the specifications at which the DC motors were running the application. For speed control, the simple solution was to daisy chain Yaskawa drives. This allowed the drives to communicate with each other, as well as synchronize their deceleration.

The Results:  The AC motors can be rated to give the same performance, or higher performance, as the DC motors.The AC drives can provide for controlled acceleration and deceleration rates. Connection between the drives allows for the synchronization of the acceleration and deceleration rates.The Yaskawa drives have the ability for the parameter setting to be extracted. This would make programming the drives to be easier by setting the parameters in one, and just copying the parameters from that one to the other two.