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
Parliamentary sovereignty. Parliamentary sovereignty is a principle of the UK constitution. It makes Parliament the supreme legal authority in the UK, which can create or end any law.Generally, the courts cannot overrule its legislation and no Parliament can pass laws that future Parliaments cannot change.Parliamentary sovereignty is the most important part of the UK constitution.eople often refer to the UK having an 'unwritten constitution' but that's not strictly true. It may not exist in a single text, like in the USA or Germany, but large parts of it are written down, much of it in the laws passed in Parliament-known as statute law.