1. Controlled Starting Current -- When an AC
motor is started "across the line," it takes as much as seven-to-eight
times the motor full-load current to start the motor and load. This
current flexes the motor windings and generates heat, which will, over
time, reduce the longevity of the motor
2. Reduced Power Line Disturbances -- Starting an AC motor across the line, and the subsequent demand for seven-to-eight times the motor full-load current, places an enormous drain on the power distribution system connected to the motor.
3. Lower Power Demand on Start -- If power is proportional to current-times-voltage, then power needed to start an AC motor across the line is significantly higher than with an Adjustable Speed AC Drive. This is true only at start, since the power to run the motor at load would be equal regardless if it were fixed speed or variable speed.
4. Controlled Acceleration -- An Adjustable Speed AC Drive starts at zero speed and accelerates smoothly on a customer-adjustable ramp. On the other hand, an AC motor started across the line is a tremendous mechanical shock both for the motor and connected load. This shock will, over time, increase the wear and tear on the connected load, as well as the AC motor
5. Adjustable Operating Speed -- Use of an Adjustable Speed AC Drive enables optimizing of a process, making changes in a process, allows starting at reduced speed, and allows remote adjustment of speed by programmable controller or process controller.
6. Adjustable Torque Limit -- Use of an Adjustable Speed AC Drive can protect machinery from damage, and protect the process or product (because the amount of torque being applied by the motor to the load can be controlled accurately). An example would be a machine jam. An Adjustable Speed AC Drive are set to limit the amount of torque so the AC motor never exceeds this limit.
7. Controlled Stopping -- Just as important as controlled acceleration, controlled stopping can be important to reduce mechanical wear and tear -- due to shocks to the process or loss of product due to breakage.
8. Energy Savings -- . Centrifugal fans and pumps follow a variable torque load profile, which has horsepower proportional to the cube of speed and torque varying proportional to the square of speed Energy savings can be sufficient to pay back the capitalized cost in a matter of a couple of years (or less), depending on the size of the motor.
9. Reverse Operation -- Using an Adjustable Speed AC Drive eliminates the need for a reversing starter, since the output phases to the motor can be electronically changed without any mechanical devices. The elimination of a reversing starter eliminates its maintenance cost and reduces panel space.
10. Elimination of Mechanical Drive Components -- Using an Adjustable Speed AC Drive can eliminate the need for expensive mechanical drive components such as gearboxes. Because the AC Drive can operate with an infinite variable speed.
2. Reduced Power Line Disturbances -- Starting an AC motor across the line, and the subsequent demand for seven-to-eight times the motor full-load current, places an enormous drain on the power distribution system connected to the motor.
3. Lower Power Demand on Start -- If power is proportional to current-times-voltage, then power needed to start an AC motor across the line is significantly higher than with an Adjustable Speed AC Drive. This is true only at start, since the power to run the motor at load would be equal regardless if it were fixed speed or variable speed.
4. Controlled Acceleration -- An Adjustable Speed AC Drive starts at zero speed and accelerates smoothly on a customer-adjustable ramp. On the other hand, an AC motor started across the line is a tremendous mechanical shock both for the motor and connected load. This shock will, over time, increase the wear and tear on the connected load, as well as the AC motor
5. Adjustable Operating Speed -- Use of an Adjustable Speed AC Drive enables optimizing of a process, making changes in a process, allows starting at reduced speed, and allows remote adjustment of speed by programmable controller or process controller.
6. Adjustable Torque Limit -- Use of an Adjustable Speed AC Drive can protect machinery from damage, and protect the process or product (because the amount of torque being applied by the motor to the load can be controlled accurately). An example would be a machine jam. An Adjustable Speed AC Drive are set to limit the amount of torque so the AC motor never exceeds this limit.
7. Controlled Stopping -- Just as important as controlled acceleration, controlled stopping can be important to reduce mechanical wear and tear -- due to shocks to the process or loss of product due to breakage.
8. Energy Savings -- . Centrifugal fans and pumps follow a variable torque load profile, which has horsepower proportional to the cube of speed and torque varying proportional to the square of speed Energy savings can be sufficient to pay back the capitalized cost in a matter of a couple of years (or less), depending on the size of the motor.
9. Reverse Operation -- Using an Adjustable Speed AC Drive eliminates the need for a reversing starter, since the output phases to the motor can be electronically changed without any mechanical devices. The elimination of a reversing starter eliminates its maintenance cost and reduces panel space.
10. Elimination of Mechanical Drive Components -- Using an Adjustable Speed AC Drive can eliminate the need for expensive mechanical drive components such as gearboxes. Because the AC Drive can operate with an infinite variable speed.
