400V Variable Frequency AC VFD Drives for Decanter Centrifuge
Decanter centrifuges are used to extract (dewater) solid materials
from liquids when they are mixed together in slurry. Decanter
centrifuges are used in many industrial applications such as:
1. Oil /solids separation (oil well drilling, refining,
2. Industrial and biological wastewater treatment
3. Food processing (olive oil, wine, fruit juice)
4. Fish processing (fish meal, fish oil)
5. Chemical slurry
A main drive motor supplies power to turn the centrifuge. AC drives
are commonly used to power the main drive motor. There are several
different types of decanter centrifuges, such as: Vertical,
horizontal, or scroll (conveyor).
· Minimize the need for gears or belts to drive the centrifuge.
· Control and maintain speed during the decanting process
· Develop high torque at very low speeds.
· Two motor applications, one for the bowl and one for the scroll.
· The bowl has a very high-reflected inertia.
· The scroll is usually in continuous regeneration, as it runs at a
slower speed than the bowl and is pulled along.
· Torque limiting on the scroll is very important.
· Some configurations require zero-speed operation of the scroll
· Dynamic braking or regenerative modules may be required if the
bowl is NOT driven by a drive.
Features of G7 series matching decanter centrifuge application
Both Frequency Detection and Speed Agree signals can interlock with
primary and auxiliary machinery as well as safety equipment while
the machine is operating.
Overtorque or Undertorque Detection
It is possible to notify the user of an impending fault before it
occurs based on the Overtorque or Undertorque Detection settings.
Multi-Step Frequency Reference
Analog inputs are not required due to 17 possible Multi-Step
Speeds. Operating speed can be adjusted for optimum performance.
- Dwell Function
- Stall Prevention
- Feed Forward Function
For accelerating high inertia loads, the user can increase the
Dwell Function setting and tune Stall Prevention. The Feed Forward
function can also be used to assist in acceleration.
- DC Injection Braking
- High Slip Braking
Although the stop time is generally long due to a large inertia
moment, it is still possible to quickly stop the drive without a
braking resistor by using the DC Braking or the High Slip Braking
- Accel/Decel Times
- Intelligent Stall Prevention
Fast acceleration and deceleration times are possible by adjusting
Accel/Decel times and using Intelligent Stall Prevention. This can
reduce overall process time.
The drive can automatically start after being shut off by using the
Fault Restart function.
Flux Vector Motor Control
Provides high starting torque and good speed regulation.
Standard Motor Used
Standard NEMA B design motor can be used to eliminate specially
Energy Saving Mode
Energy saving operation can be implemented at full speed during
Power range of G7 VFD
Voltage: 400VAC (380VAC – 460VAC)
Power: 22kw/30HP – 1000kw/1250HP
Specification of G7 VFD
150% rated current 1min.
Close-loop vector control, sensor-less vector control, V/F control
150% 1hz (with PG 0hz)
±0.2% (With PG ±0.02%)
Setting frequency resolution
Digital command 0.01hz; analog command 0.03hz/60hz
Output frequency resolution
Frequency setting signal
Over voltage, under voltage, over load, relay, overheat speed
stall, grounding, instant power cut compensation( within 2 sec for
operation mode. Continue to operate after the power is available),
Charging protection( not to display when the dc voltage of main
circuit is less than 50v)
forced air cooling
Less than 0.2g for 20hz
Ambient temperature / Humidity
-10 Degrees~+40 Degrees / 20~90%Rh (no condensation)
A variable-frequency drive (VFD) is a system for controlling the
rotational speed of an alternating current (AC) electric motor by
controlling the frequency of the electrical power supplied to the
motor. A variable frequency drive is a specific type of
adjustable-speed drive. Variable-frequency drives are also known as
adjustable-frequency drives (AFD), variable-speed drives (VSD), AC
drives, microdrives or inverter drives. Since the voltage is varied
along with frequency, these are sometimes also called VVVF
(variable voltage variable frequency) drives.