Question 1
What is the primary advantage of using a Variable Frequency Drive (VFD) for pump applications?
Question 2
When selecting a VFD for a constant torque load (like a conveyor), which rating is most important?
Question 3
What is the primary purpose of a DC link choke in a Variable Frequency Drive (VFD)?
Question 4
For a constant torque load, which VFD rating is required?
Question 5
Which of the following is a specific requirement for the installation of a variable frequency drive (VFD) to minimize electromagnetic interference (EMI)?
Question 6
What is the primary function of a VFD's 'DC Bus' section?
Question 7
Which of the following is a critical installation requirement for the output conductors of a Variable Frequency Drive (VFD)?
Question 8
Which of the following is a requirement for the output leads of a variable frequency drive (VFD) to minimize electromagnetic interference (EMI)?
Question 9
What is the primary function of the 'rectifier' section within a Variable Frequency Drive (VFD)?
Question 10
What is a primary advantage of using a Variable Frequency Drive (VFD) over an across-the-line starter for an industrial pump motor?
Question 11
What is the primary function of a variable frequency drive (VFD) in an industrial pump application?
Question 12
What is the primary benefit of installing a 'shielded' cable for the output of a variable frequency drive (VFD)?
Question 13
A three-phase motor shows a 5% voltage imbalance between phases under load. What is the most appropriate action for the electrician?
Question 14
A large variable frequency drive (VFD) installation is causing nuisance tripping of upstream ground-fault devices. What is a likely contributing factor?
Question 15
In a Variable Frequency Drive (VFD) installation, why is shielded cable often used for the output to the motor?
Question 16
What is the primary function of a Variable Frequency Drive (VFD)?
Question 17
A Variable Frequency Drive (VFD) controls the speed of an AC motor by varying the:
Question 18
Which type of motor control device is used to change the speed of an AC induction motor?
Question 19
When a motor is controlled by a VFD, what type of cable is often recommended to reduce noise?