VFD-ի հարցերը – kỹունգների համակարգչային брошюра
1). Ինչ է VFD-ը և ինչ աշխատանք կատարում է էլեկտրական համակարգում
VFD (փոփոխական հաճախականության դրայլ)-ը, որը նաև հայտնի է որպես կարգավորելի հաճախականության դրայլ (AFD), կարգավորելի արագության դրայլ (ASD) կամ AC դրայլ, կառավարում է էլեկտրական դիմացի էներգիայի աղբյուրի հաճախականությունը և լարումը։ VFD-ն կարող է նաև կառավարել դիմացի սկզբնական և վերջնական արագությունը համապատասխանաբար սկսման և դադարի ժամանակ։
VFD-ները հաճախ տեղադրվում են էլեկտրական համակարգերում էներգիայի աղբյուրի և դիմացի միջև։ Ներգրավված փոփոխական հոսանքը փոխակերպվում է ուղղահայաց հոսանքի, որը հետո կրկին փոխակերպվում է փոփոխական հոսանքի աhaited frequency and voltage. The motor then rotates at the desired speed as a result of the VFD feeding it modified AC electricity.
A wide range of electrical systems can benefit from the flexibility and strength of VFDs by operating more effectively and reliably.
2). Describe the fundamental working principle of a VFD
A variable frequency drive (VFD) is a type of a motor controller that controls the frequency and voltage supplied to an electric motor. The variable-frequency drive’s operation is primarily determined by its changing speeds & soft start or soft stop features.
3). What are the primary elements of a VFD circuit and what do they do?
A VFD circuit’s main components are:
Rectifier: A device that convert AC input voltage to DC voltage.
DC bus: A capacitor bank which stores the rectifier’s direct current voltage.
Inverter: A device that converts DC voltage to alternating current voltage.
PWM controller: This device regulates the frequency & duty cycle of the output voltage.
Filter: Removes high-frequency noise from output voltage.
4). In motor control applications, what are the benefits of using VFDs?
VFDs provide numerous benefits in the motor control applications, such as:
Energy efficiency
Enhanced process management
Motor deterioration is diminished
Longer motor life
Reduced vibration and commotion (vibration)
Improved security
VFDs are a versatile and potent instrument that can be used to enhance the performance, efficiency, & dependability of a broad range of electrical systems.
5). Explain the distinction between vector control & V/f (Volts per Hertz) for VFDs.
| VFD Vector Control | VFD V/f Control |
| VFD vector control is an even more advanced motor control approach than V/f control. It uses input from the motor to more precisely manage the speed and torque. Vector control is frequently employed in high-performance, high-accuracy applications such as machine tools, robotics, & food and beverage processing. | VFD V/f control is a less complicated and less costly way of motor control. It maintains a steady voltage-to-frequency ratio, which maintains the magnetic flux in the electric motor constant. V/f control is frequently employed in low-performance applications such as fans & pumps. |
6). What variables should be taken into consideration while choosing a VFD for a certain application?
The following criteria should be considered while considering a VFD for a certain application:
The form of motor being controlled must be appropriate with the VFD.
Motor power rating: The VFD’s power rating must be equal to (or) greater than its motor’s power rating.
Speed range: The VFD should be able to give the motor with the appropriate speed range.
Torque requirements: The VFD should be able deliver the motor with the necessary torque.
Duty cycle: The VFD should be able to manage the motor’s duty cycle.
Environmental conditions: The VFD must be able to function in the environment in which it shall be installed.
7). How can a variable frequency drive (VFD) help in energy savings & motor protection?
VFD contribute to energy savings & motor protection by:
Motor speed matching to load necessities: This may reduce as much as 70% of energy consumption, particularly in applications wherein the load varies often, such as fans & pumps.
Reduced starting current: VFDs can lower starting current by as much as 80%, which can lengthen motor life and reduce electrical system wear and tear.
Overload protection, voltage spike protection, & other electrical problems: This may be able to prevent the motor from burning out, saving time & money on repairs & replacements.
8). What is meant by motor derating, & why is it essential when using a VFD?
Motor derating is the process of lowering an electric motor’s rated power output. When utilizing a VFD, it is critical to derate the motor since the VFD may cause the motor to function at higher temperatures compared to when it was powered straight from the line.
A number of factors can influence the quantity of derating required, such as:
The motor types
The type of VFD
The outside temperature
The motor’s duty cycle
Some of the factors explaining why motor derating is essential when utilizing a VFD include:
To avoid overheating the motor
To lengthen the life of the motor
To increase the motor’s dependability
To lessen the possibility of motor failure
9). Describe the most typical difficulties (or) issues that may arise with VFDs and how would solve them.
The following are examples of common problems or concerns that might occur with VFDs:
Overheating: If a VFD is not adequately vented or is operated at an excessive load, it might overheat.
Ground faults: Ground failures can arise if the VFD is not correctly grounded (or) if there is an issue with the wiring.
Noise and vibration: If a VFD is not properly placed or if there is an issue with the motor or the VFD itself, it can produce noise and vibration.
Tripping: If a VFD detects a ground fault, an overload, or similar problem, it will trip.
