A variable-frequency drive (VFD) (also termed adjustable-frequency drive, variable-speed drive, AC drive, micro drive or inverter drive) is a type of adjustable-speed drive used in electro-mechanical drive systems to control AC motor speed and torque by varying motor input frequency and voltage.ariable-frequency drives are also categorized by the following load torque and power characteristics: 1  Variable torque, such as in centrifugal fan, pump, and blower applications. 2  Constant torque, such as in conveyor and positive-displacement pump applications.
For example, the UK is a unitary state (for the most part) whereas the US is a federation. A parliamentary form of government simply means that the executive branch/ministers/cabinet are part of the legislative body. Both unitary and federal states can have parliaments. For example, India is a federation with a parliamentary system where as the UK is a unitary state with a parliamentary system. m200220232
Lesson Summary. Parliamentary government is a type of democratic government in which the political party that wins the most seats in the parliament forms the government. That party will choose a leader as Prime Minister or Chancellor, who acts as the head of the government.nstructor: Erin Carroll. In this lesson you will learn what a parliamentary government is, and how it functions with examples like Australia and Germany. Then you'll learn some of the advantages and disadvantages of a parliamentary system of government.