ADT inverter in centrifugal dehydrator
AD300 Series AC drive for centrifugal water extractor
I Techniques requirements of centrifugal extractor
1. The centrifugal extractor extracts the water from the material inside the high speed spinning stainless drum. It is widely used in textile, printing & dyeing, ceramic, chemistry, ore dressing, hotel laundry washing etc.
2. The load is very typical low damping high inertia load. So the inverter should conquer the problems such as over current during starting acceleration and the over voltage during deceleration to stop.
3. The inverter is not supposed to trip off during the acceleration and deceleration with motor Max rated current.
4. The inverter is required to has high torque output at low frequency and avoids slipping during the stop process.
II System configuration of centrifugal water extractor
AD300 series sensorless vector control VFD is used. Install the brake resistors according to the motor power. If the motor power is higher than 22kW, the external brake unit should be also used.
iii Centrifugal extractor’s control system features
1. The control scheme is simple with easy commissioning, easy operation and maintenance.
2. Open-loop current vector control is adopted. The frequency inverter can output 150% of rated torque at frequency 1.0Hz. The starting and braking is forceful and stable.
3. The current amplitude limit function protects the inverter from tripping during acceleration and deceleration with rated current. It can automatically extend or shorten the acc/dec time according to the weight of extracted material in the drum. The extracting efficiency is high.
4. The DC brake torque is reliable. The drum stop stable without slipping within preset time.
5. Flying start function when the drum is in spinning status.
6. When there is power failure from the power grid, the high inertia energy from spinning drum will be converted into electricity energy fed back to the inverter and consumed by the the braking resistors. This avoid the long time slipping and coast to stop situation in case of power failure.