660V Medium Voltage Variable Frequency Drives for Water Pumps
A pump is a machine or device for raising, transferring, or
compressing fluids. Pumps represent the largest single use of power
in industry (31%) by motor driven equipment. Process variables,
including pressure and flow of gases and liquids, have long been
regulated using mechanical clutches, throttles, and adjustable
inlet guide vanes. Pumps often operate as a variable torque load, a
load that increases as the speed increases. These mechanisms waste
energy, require frequent maintenance, and provide inaccurate
control.
Pumps have two main categories:
1. Positive displacement pumps force a fixed volume of fluid from
inlet to discharge with each stroke or rotation. (e.g.,
reciprocating, rotary, or screw type pumps)
2. Centrifugal pumps are the biggest class of pumps, which use the
fluid's own momentum to build up pressure or head. Centrifugal
pumps use centrifugal and hydrodynamic forces to create pressure
that moves the fluid from inlet to discharge.
Pumps can also be classified by principle of operation and drive
requirements.
· Principle of Operation Application Served
· Materials of Construction
· Liquid Being Pumped
· Shaft Orientation (Vertical, Horizontal)
· Number of Stages
· SuctionPortArrangement
Application Challenges
· Reduce energy costs
Motors use less energy as speed is reduced.
· Reduce demand charges
Drives reduce motor starting current 8-10 times.
·Variable and constant torque load characteristics, depending on
pump type.
·The motor may spin backwards due to pump backpressure when
stopped.
·Control of pressure and flow is desired.
·High reliability.
·Wide horsepower range for different pump sizes.
·Environmentally friendly (harmonic standards).
·Network communications.
·Prevention of water hammer, pipe stress, valve, and pump seals and
cavitation prevention.
Features of G11 matching extruder application
Features | Benefits |
Open Loop Vector and V/Hz Control with Torque Compensation | Provides excellent breakaway torque for thick materials and
constant torque to maintain mixing speeds under heavy loads. |
Overtorque Detection | Provides early warning of damaging torque levels as a result of
seizing mixer blades. |
Torque Reference programmable to an analog output | The applied mixing torque is fine tuned or adjustable for different
material. |
Preset frequency reference | Preset mixing patterns can be established for different materials. |
Auto-Restart after momentary power loss | Mixing can quickly restart after fault or momentary power loss.
This keeps perishable foods from spoiling in process. |
Power loss Ride-Through | The mixing process in not interrupted during brief power loss (<
5 ms). |
Power range of G11 VFD
Voltage: 660VAC (450VAC – 690VAC)
Power: 22kw/30HP – 400kw/535HP
Specification of G11 VFD
Item | Specification |
Input frequency | 50/60Hz |
Output frequency | 0-400Hz |
Overload current | 150% rated current 1min. |
Control mode | Close-loop vector control, sensor-less vector control, V/F control |
Starting torque | 150% 1hz (with PG 0hz) |
Control precision | ±0.2% (With PG ±0.02%) |
Torque precision | ±5% |
Setting frequency resolution | Digital command 0.01hz; analog command 0.03hz/60hz |
Output frequency resolution | 0.01Hz |
Frequency setting signal | -10V~+10V；0~+10V(20kΩ)；4~20mA |
Protection function | 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) |
Enclosure | IP20 |
Cooling mode | forced air cooling |
Vibration | Less than 0.2g for 20hz |
Ambient temperature / Humidity | -10 Degrees~+40 Degrees / 20~90%Rh (no condensation) |
Tips:
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.
