Magnetic Polarity: It is a fundamental principle of winding that adjacent poles must be wound to give opposite magnetic polarity. This does not mean that the coils actually have to be wound in this direction before being placed into the stator. It does mean that the winding must be connected so that, if the current proceeds through one pole in a clockwise direction, it must proceed through the next pole in a counterclockwise direction. This principle is used to determine the correctness of connection diagrams.
Marine Duty Motor: A specialized motor designed for use onboard ships. Motors are designed per IEEE 45 motor specification.
Master Drive: A drive that sets the reference for one or more follower drives.
Mechanical Degree: The popular physical understanding of degrees (360 degrees = 1 revolution).
Megohm Meter: A device used to measure an insulation system's resistance. This is usually measured in megohms and tested by passing a high voltage at low current through the motor windings and measuring the resistance of the various insulation systems.
Modular Construction: The major circuit elements are mounted in replaceable modules which can readily be removed and replaced. Equipment can be serviced without delay.
Module: A unit of circuit elements usually packaged so it can be readily replaced.
Motor Constant: The ratio of motor torque to motors input current (motor torque per amp).
Multi Motor Operation: A system in which one controller operates two or more motor simultaneously, maintaining a constant ratio between the speeds of the motors.
Multi Speed Motor: An induction motor that can obtain tow, three, or four discrete (fixed) speeds by the selection of various stator winding configurations.
Mush Wound Coils: Also called random wound coils -- Where the turns are wound without definite placement, or, at random. Most small motors up to 25 HP are mush wound although motors up to 150 HP have been successfully wound without formed coils. The limit is not the horsepower, but did the manufacturer allow enough slot space for the wasteful, random wound coil.
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