vad är en VFD?
Vilken komponent är viktig för att skydda en VFD?
Överströmsskydd
Vilken funktion har en VFD i industriell automation?
Att styra hastigheten på en motor
Vilken typ av motor används oftast med VFD?
Asynkronmotor
Kan en VFD användas för att styra flera motorer samtidigt?
Ja
Vilken av följande är en fördel med att använda VFD?
Energibesparing
Vad är en vanlig applikation för VFD inom industriell automation?
Pumpstyrning
Vilken typ av signal används för att styra en VFD?
Analog signal
Vad står VFD för?
Variabel frekvensdrivare
VFD och induktionsmotor
Operation of a VFD is based on the fact that the speed of an induction motor is directly proportional to the frequency of the voltage supplied to the motor. When frequency increases, speed also increases, and when frequency reduces, the speed will also reduce
ASD lika med VFD
A VFD is a device used to vary the speed of Asynchronous or Synchronous (AC) electric motors by varying the frequency and voltage supplied. A VFD can also be referred to as an Adjustable Speed Drive (ASD) or inverter. It is the most effective way of controlling the speed of an induction motor.
sykron motor
A synchronous motor runs at synchronous speed (the speed of the rotating magnetic field of the stator) while an asynchronous (induction) motor’s speed is slightly less than synchronous speed. In the previous chapter, it was mentioned that synchronous speed is determined by the frequency of the voltage source and the number of poles, as shown by the following formula:
varierad hastighet
If an application requires a varying speed, a VFD can be used to increase or reduce the speed of the motor, and it does so by varying the frequency and voltage. Some of the companies in the VFD industry include Siemens, Rockwell Automation, Yaskawa Electric Corporation, and General Electric. This book focuses on the General Electric VFD.
converter
konverterar från AC ström till DC ström
DC link och ev induktor
steg två efter Converter, ev med en induktor (ett motstånd) som hanterar ev brus så nästa steg i signalen blir så ren som möjligt
inveterare?
This is the third stage, which converts the DC power from the DC link into a three-phase AC output. This stage comprises of a power-switching device such as a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), or an Insulated Gate Bipolar Transistor (IGBT), or a thyristor. The output of an inverter is not a pure sine wave but an approximation, based on the principle of Pulse Width Modulation (PWM), which is the major inverter technology.
fördel VFD (inverterare, ASD)
ASD adjustable speed drive
A VFD extends motor life and reduces maintenance costs because it starts the motor by ramping it up to the operating speed, rather than starting it abruptly as a direct online starter would do.
fördel vfd
A VFD has built-in safety features that provide protection for both the motor and the VFD itself. The VFD can automatically stop operation when a fault occurs. The built-in safety features eliminate the cost of additional safety components.
fördel vfd
spar energi och A VFD offers flexible control of AC motors. With VFD, various options are available for controlling a motor. It can use push buttons, selector switches, and a potentiometer, and can even be operated through a Programmable Logic Controller (PLC) or other form of industrial controller.
fördel VFD (Inverterare)
A VFD reduces disturbances in the power line. When AC motors are started across the line, they can demand up to 600% of the full load current, depending on the capacity of the motor. This can cause a significant disturbance or a short-duration reduction in voltage (voltage sag) in the power system connected to it. Sensitive equipment connected to the same power distribution system can be interrupted due to the low voltage that occurs as a result of the disturbances. A VFD eliminates voltage sag or disturbance in a power line since it starts at 0V and ramps up to the required speed.
nackdel VFDs
Harmonics, orsakar They are high-frequency signals that are superimposed on the fundamental waveform, creating a distorted waveform. They can cause overheating of motors and transformers, premature failure of circuit breakers, incorrect operation of electronic instruments, and other issues.
åtgärd. ot harmonics i VFD?
A remedy for harmonics caused by a VFD is the use of an AC line reactor (choke) or filter.