Adjustable speed drive (ASD) also termed as a variable-speed drive (VSD) is used to describe equipment that helps to control the speed of machinery. They’re used in mechanical equipment which are powered by motors.
The drives offer accurate electrical motor control, in such a way that motor speeds can be ramped up and down and maintained at speeds required. Although, motors can be operated without the help of any drive.
- Controlled Starting Current:
Usually when an ac motor is started “across the line,” it takes about as seven-to-eight times to start the motor and load.
By utilizing an adjustable speed drive, the considerably reduced starting current expands the life of an ac motor. The benefits are less wear & tear on the motor which translates to extend motor life and less motor rewinds.
- Controlled Stopping:
Controlled stopping assists diminish product loss because of breakage or mechanical wear and tear credited to shocks to the process.
- Reverse Operation:
Utilizing an adjustable speed drive eradicates the requirement for a reversing starter since the output phases to the motor can be electronically changed devoid of mechanical devices. Getting rid of the reversing starter abolishes its maintenance cost and reduces panel space.
- Lower Power Demand on Start:
The power required to begin an ac motor across the line is considerably higher than an adjustable speed drive. This is accurate only at the start, since the power to run the motor at load would be equal despite its fixed speed or variable speed.
- Adjustable Operating Speed:
Utilizing an adjustable speed drive allows process optimization and making changes in a process. It also permits starting at reduced speed and allows remote adjustment of speed by a programmable controller or process controller.
- Energy Savings:
Centrifugal fan and pump loads operated with adjustable speed drives decrease because of energy consumption. If the speed of a fan is cut in half, the horsepower required to operate the fan is cut by a factor of eight.
The energy savings could connect to a Return on Investment (ROI) of less than 2yrs.
- Elimination of mechanical drive components:
Using an adjustable speed drive can eradicate the requirement for pricey mechanical drive components like gearboxes. Because the ac drive can function with an infinitely variable speed, it can transport the low- or high-speed required by the load with no speed-varying devices between the motor and load.
This way, it eliminates maintenance costs and reducing floor-space requirements.
- Adjustable torque limit:
Utilizing an adjustable speed drive can guard machinery against damage and guard the process because the quantity of torque being applied by the motor to the load can be controlled precisely.
- Reduced power line disturbances:
Commencing an ac motor across the line and the demand for starting current places a huge drain on the power distribution system connected to the motor.
Normally, the supply voltage sags can cause sensitive equipment connected to the similar distribution system to trip. Products such as computers, sensors, proximity switches, and contractors are voltage sensitive and can drop-out when a huge ac motor is started in close proximity. Making use of an adjustable speed drive eradicates this voltage sag.
