A
The client installed one ABB ACS400 20HP drive to run two 7.5 HP drive motors.
The system appears to unstable at speed. It makes fiberboard, and there is a cutting saw on the end. The saw is placed at an angle and an encoder drives the saw. The saw cuts the material while it is moving. The cut appears wavy after installing the new drive. They claim the cut was laser-straight using an old SquareD OmegaPac drive.
I amp checked the motors and one draws 6 amps while the other draws 4 amps. They say ganging the drives together is necessary to keep the upper and lower belts syncronized.
I suggested that it is impossible for a single drive to supply the correct voltage to each motor, since the motors have different load characteristics. If, for example the upper drive has a momemtary need for more current to maintain the speed, the drive will detect the need but and supply it by extending the pulse width, but both motors will see this adjustment.
They theorize that the motor that does not need the additional current will not draw more current or change its slip characteristics. I am not convinced that this is a valid configuration.
Does anyone here have any experience with the problems of driving 2 motors from a single drive?
Thanks
Alex Paulsen
The system appears to unstable at speed. It makes fiberboard, and there is a cutting saw on the end. The saw is placed at an angle and an encoder drives the saw. The saw cuts the material while it is moving. The cut appears wavy after installing the new drive. They claim the cut was laser-straight using an old SquareD OmegaPac drive.
I amp checked the motors and one draws 6 amps while the other draws 4 amps. They say ganging the drives together is necessary to keep the upper and lower belts syncronized.
I suggested that it is impossible for a single drive to supply the correct voltage to each motor, since the motors have different load characteristics. If, for example the upper drive has a momemtary need for more current to maintain the speed, the drive will detect the need but and supply it by extending the pulse width, but both motors will see this adjustment.
They theorize that the motor that does not need the additional current will not draw more current or change its slip characteristics. I am not convinced that this is a valid configuration.
Does anyone here have any experience with the problems of driving 2 motors from a single drive?
Thanks
Alex Paulsen