M

Magnet

A body that possesses the property of magnetism is called a magnet.

Magnetism

Magnetism is a property associated with materials that attract iron and iron alloys.

Megohmmeter

Megohmmeter commonly called a Megger®, is used to detect insulation failure within motors and transformers.

Matter

Any substance that has weight (mass) and occupies space.

Magnetic Field

When current flows in a wire, it creates a magnetic effect around the wire which is called magnetic field. The magnetic field is specified by a direction as well as a magnitude.

Multimeters

Multimeters are designed to measure voltage, current, and resistance.

Magnetic Domains

A ferromagnetic material contains small regions called magnetic domains.

Domains are acicular (needle-shaped) microscopic crystals that contain from 1012 to 1015 atoms.

Magnetic Flux

A total number of lines of magnetic force passing through any surface placed perpendicular to the magnetic field. It is denoted by φ (Greek Letters Phi).

Magnetic Lines of Force

Magnetic lines of force are used to represent a magnetic field. Faraday introduced the idea of flux lines to simplify the analysis of magnetic fields. One must remember that the field is continuous and exists between, as well as along, the lines of force.

Magnetomotive Force (MMF)

The force produced by current through a coil of wire is called magnetomotive force (mmf)

Magnetic Field Intensity

Magnetomotive force, ℑ, per unit length, is called the magnetic field intensity H.

Mutual Induction

Mutual induction is the phenomenon in which a changing current in the coil induces emf in another coil.

Magnetic Flux Density

A measure of the number of magnetic lines of force per unit of cross-sectional area.

Magnetic circuit

 The region containing essentially all the flux, such as the core of a transformer.

Maximum power

The maximum output that an electric machine is capable of developing at rated voltage and speed.

Mutual inductance

 The common property of two electric circuits whereby an electromotive force is induced in one circuit by a change of current in the other circuit.

Manual Ranging

 A term used to describe test equipment where the readout range is selected. For example, if you are measuring a voltage under 2 volts, you would turn a knob to select the 0 – 2 V range.

Motor Starter

 A device used to supply full line voltage to a motor and include overcurrent protection.

Motor Nameplate

 Every electric motor is labeled with a motor nameplate. The motor nameplate contains information about important motor parameters. NEMA (National Electrical Manufacturers Association) specifies the nameplate layout and data.

Metric Units

 These are measurements units used in most of the world. Typical units are meters, centimeters, kg (kilogram), N (newton’s), and seconds.

Magnetic Sensor

A sensor that uses reed switches that are magnetically-actuated.

About Ahmad Faizan

Mr. Ahmed Faizan Sheikh, M.Sc. (USA), Research Fellow (USA), a member of IEEE & CIGRE, is a Fulbright Alumnus and earned his Master’s Degree in Electrical and Power Engineering from Kansas State University, USA.

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