Chat with AIExam 15: Variable Frequency Drive Principles
____ is what happens when the induction motors stops functioning like a motor, and starts functioning like a generator instead.
(39) 
VerifiedA
VFDs are usually designed for operating characteristics of ____ motors.
(32) VerifiedB
Name and describe the four stages of the VFD.
(33) VerifiedRectifier (sometimes called a converter)
This is the stage of the VFD that rectifies the AC input power to DC power.Some VFDs include additional filtering circuitry to negate any harmonic conditions that could cause power supply problems.DC Bus (sometimes called the DC link)
The DC bus stage of the VFD prepares the DC power from the rectifier stage, for use by the inverter stage.Inverter
The input to the inverter is the DC power on the DC bus.The inverter, under control of the control and regulation stage of the VFD, changes the DC bus power to a controlled frequency AC on the output.Control and regulation
In this section, complex mathematical algorithms are used to separate the torque producing current from the magnetizing current.The control and regulation section of the VFD senses the CEMF of the motor to make adjustments and regulate the inverter section output.
The ____ section of the VFD senses the CEMF of the motor to make adjustments and regulate the inverter section output.
(32) It's estimated that the average home has about ____ electric motors.
(37) The ____ changes the DC bus power to a controlled frequency AC on the output.
(31) Quadrants 1&3 are referred to as _______________ quadrants, because both torque and rotation are in the same direction.
(42) ____ torque mechanical loads are machine applications where the torque loading is a function of the speed; low torque at low speeds, and higher torque at higher speeds.
(40) _______________ torque applications require the same amount of driving torque throughout the entire operating speed range.
(35) The mode of operation for motors operated above their rated frequency is called ____ horsepower.
(32) The ____ stage of the VFD prepares the DC power from the rectifier stage, for use by the inverter stage.
(32) The _______________ principle is basically a ratio of the voltage applied to the motor, divided by the frequency applied to the motor.
(32) One benefit of VFD technology is that the motor can be operated at different speeds above and below its rated _______________ speed.
(41) When using the _______________ contactor across the line full voltage motor starting method, the electrical supply power to the motor is either full on, or completely off.
(34) Quadrants 2&4 are referred to as _______________ quadrants, because torque and rotation are in opposite directions.
(33) 
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