eddy-current drive
An adjustable speed drive in which a constant speed AC motor drives a drum assembly. Torque is transmitted from the input drum to an output rotor and output shaft by varying a magnetic field between the input drum and the output rotor.

efficiency
Ratio of power output to power input, expressed as a percent. Motor efficiency is the effectiveness with which the motor converts electrical energy into mechanical energy. Drive efficiency is the effectiveness with which the drive converts fixed voltage electrical energy to its output electrical energy.

EMF
Electromotive force. Electrical pressure, the potential that causes electrons to flow through a circuit. Voltage.

EMI
Electromagnetic interference. Any electrical disturbance that interferes with the operation of a piece of electronic equipment. This is generally used to describe interference which is through the building's power wires.

enclosure
The housing in which the adjustable frequency drive is mounted.
The IEC standard of enclosures are given as degree of IP, as example IP 22:
The first digit refers to the personal protection and protection against intrucion of foreign bodies:
   0: Non-protected
   1: Proctected against solid objects greater than 50 mm
   2: Proctected against solid objects greater than 12 mm
  3: Proctected against solid objects greater than 2.5 mm
  4: Proctected against solid objects greater than 1 mm
  5: Dust protected
  6: Dust tight

The second digit refers protection against harmfull ingress of water:

   0: Non-protected
  1: Proctected against dripping water
  2: Proctected against dripping water when tilted up to 15ź
  3: Proctected against spraying water
   4: Proctected against splashing water
   5: Proctected against water jets
   6: Proctected against heavy seas
   7: Proctected against effects of immersion
   8: Proctected against submersion

In U.S.A. enclosures are defined by NEMA for the intended environment. Some common types are:
NEMA Type 1
For indoor, dry applications. Protects against accidental human contact.
NEMA Type 3R
For outdoor applications. Protects against falling water (rain) and ice buildup per a specific test.
NEMA Type 4
For outdoor and hose down applications. Protects against water from any angle (per a specific test).
NEMA Type 12
For indoor industrial applications where exclusion of oil, grease, dust, lint and filings as well as water is required.

electrostatically shielded transformer
A transformer that includes a metallic enclosure that is designed to contain the electrostatic field created by the transformer.

ETL
Electrical Testing Laboratories A product safety certification and listing service generally accepted by federal, state and local authorities in the United States.

extended speed
Speeds greater than the base speed of a motor. With an adjustable frequency drive, this is commonly achieved using constant horsepower extended frequency operation. With this method, motor torque decreases as the motorís speed increases beyond base speed.