{"id":111,"date":"2019-08-30T11:34:22","date_gmt":"2019-08-30T11:34:22","guid":{"rendered":"https:\/\/www.axcontrol.com\/blog\/?p=111"},"modified":"2022-10-28T15:21:36","modified_gmt":"2022-10-28T15:21:36","slug":"industrial-automation-terms","status":"publish","type":"post","link":"https:\/\/www.axcontrol.com\/blog\/2019\/industrial-automation-terms\/30\/08\/","title":{"rendered":"Industrial Automation Terms You Should Know"},"content":{"rendered":"\n
\"Industrial
Industrial Automation covers a lot of ground. <\/figcaption><\/figure><\/div>\n\n\n

Here’s a list of industrial automation terms you may need to be defined as you’re looking at our extensive catalog of parts. <\/p>\n\n\n

A <\/strong><\/p>\n\n\n\n

AC (ALTERNATING CURRENT)<\/strong><\/h3>\n\n\n\n

The commonly available electric power supplied, an AC generator and is distributed in single or three-phase forms. AC current changes its direction of flow (cycles).<\/p>\n\n\n\n

AC MOTORS<\/a><\/strong><\/h3>\n\n\n\n

A motor (see motor definition) operating on AC current that flows in either direction (AC current). There are two general types: induction, and Synchronous.<\/p>\n\n\n\n

ACTIVE IRON<\/strong><\/h3>\n\n\n\n

The amount of steel (iron) in the stator and rotor of a motor. Usually, the amount of active iron is increased or decreased by lengthening or shortening the rotor and stator (they are generally the same length).<\/p>\n\n\n\n

AIR GAP<\/strong><\/h3>\n\n\n\n

The space between the rotating (rotor) and stationary (stator) member in an electric motor.<\/p>\n\n\n\n

AIR PRESSURE SWITCH<\/strong><\/h3>\n\n\n\n

Used on motors with blowers to measure the difference in pressure across the filter so as to detect a clogged filter.<\/p>\n\n\n\n

AIR TEMPERATURE SWITCH<\/strong><\/h3>\n\n\n\n

A device used in air hooded motors to detect the temperature of the exhausted air. When used in this manner an air temperature switch will detect blockage in the cooling air system or long-term motor overload.<\/p>\n\n\n\n

ALTITUDE<\/strong><\/h3>\n\n\n\n

The atmospheric altitude (height above sea level) at which the motor will be operating; NEMA standards call for an altitude not exceeding 3,300 ft. (1,000 meters). As the altitude increases above 3,300 ft. and the air density decreases, the air stability to cool the motor decreases – for higher altitudes, higher grades of insulation or a motor derating are required. DC motors require special brushes for high altitudes.<\/p>\n\n\n\n

AMBIENT TEMPERATURE<\/a><\/strong><\/h3>\n\n\n\n

The temperature of the surrounding cooling medium, such as gas or liquid, which comes into contact with the heated parts of the motor. The cooling medium is usually the air surrounding the motor. The standard NEMA rating for ambient temperature is not to exceed 40\u0192C.<\/p>\n\n\n\n

ANTI-FRICTION BEARING<\/strong><\/h3>\n\n\n\n

An anti-friction bearing is a bearing utilizing rolling elements between the stationary and rotating assemblies.<\/p>\n\n\n\n

ARMATURE<\/strong><\/a><\/h3>\n\n\n\n

The portion of the magnetic structure of a DC or universal motor which rotates<\/p>\n\n\n\n

ARMATURE CURRENT, AMPS<\/strong><\/h3>\n\n\n\n

Rated full load armature circuit current.<\/p>\n\n\n\n

ARMATURE INDUCTANCE, MH<\/strong><\/h3>\n\n\n\n

The armature inductance in milli-henries (saturated).<\/p>\n\n\n\n

ARMATURE REACTION<\/strong><\/h3>\n\n\n\n

The current that flows in the armature winding of a DC motor tends to produce magnetic flux in addition to that produced by the field current. This effect, which reduces the torque capacity, is called armature reaction and can affect the commutation and the magnitude of the motor’s generated voltage.<\/p>\n\n\n\n

ARMATURE RESISTANCE, OHMS<\/strong><\/h3>\n\n\n\n

The armature resistance is measured in ohms at 25\u0192 C. (cold)<\/p>\n\n\n\n

AXIAL THRUST<\/strong><\/h3>\n\n\n\n

The force or loads that are applied to the motor shaft in a direction parallel to the axis of the shaft. (Such as from a fan or pump) <\/p>\n\n\n\n

<\/code><\/pre>\n\n\n
<\/p>\n\n\n
B<\/strong><\/p>\n\n\n\n
BACK END OF A MOTOR<\/strong><\/h3>\n\n\n\n
The back end of a normal motor is the end that carries the coupling or driving pulley. (NEMA) This is sometimes called the drive end (D.E., pulley end P.E.), etc.<\/p>\n\n\n\n
BASE SPEED, RPM<\/strong><\/h3>\n\n\n\n
The speed at which a DC motor develops at rated armature and field voltage with a rated load applied.<\/p>\n\n\n\n
BEARINGS<\/strong><\/h3>\n\n\n\n
Are used to reduce friction and wear while supporting rotating elements. For a motor,  it must provide relatively rigid support for the output shaft.<\/p>\n\n\n\n
The bearing acts as the connection point between the rotating and stationary elements of a motor. There are various types such as roller, ball, sleeve (journal), and needle.<\/p>\n\n\n\n
The ball bearing is used in virtually all types and sizes of electric motors. It exhibits low friction loss, is suited for high-speed operation, and is compatible with a wide range of temperatures. There are various types of ball bearings such as open, single shielded, or sealed. <\/p>\n\n\n\n
BEARING LIFE<\/strong><\/h3>\n\n\n\n
Rating life, L10<\/sub> (Bl0<\/sub>), is the life in hours or revolutions in which 90% of the bearings selected will obtain or exceed. Median life (average life), L50<\/sub>(B50<\/sub>)
<\/p>\n\n\n\n
BRAKES<\/strong><\/h3>\n\n\n\n
An external device or accessory that brings a running motor to a standstill and\/or holds a load. Can be added to a motor or incorporated.<\/p>\n\n\n\n
BRAKING TORQUE<\/strong><\/h3>\n\n\n\n
The torque required to bring a motor down to a standstill. The term is also used to describe the torque developed by a motor during dynamic braking conditions.<\/p>\n\n\n\n
BREAK AWAY TORQUE<\/strong><\/h3>\n\n\n\n
(See Locked rotor torque)<\/p>\n\n\n\n
BREAKDOWN TORQUE<\/strong><\/h3>\n\n\n\n
The maximum torque a motor will develop at rated voltage without a relatively abrupt drop or loss in speed.<\/p>\n\n\n\n
BRUSH<\/strong><\/h3>\n\n\n\n
A piece of current-conducting material (usually carbon or graphite) that rides directly on the commutator of a commutated motor and conducts current from the power supply to the armature windings. <\/p>\n\n\n
<\/p>\n\n\n
C<\/strong><\/p>\n\n\n\n
“C” FLANGE<\/strong><\/h3>\n\n\n\n
A type of flange used with close-coupled pumps, speed reducers, and similar applications where the mounting holes in the f flange are threaded to receive bolts. Typically, the “C” Flange is used where a pump or similar item is to be overhung on the motor. The “C” type flange is a NEMA standard design and available with or without feet.<\/p>\n\n\n\n
CANOPY (DRIPCOVER)<\/strong><\/h3>\n\n\n\n
A protective cover placed on the top of a motor being mounted vertically to protect it from liquids or solids that might drop onto the motor. (It acts similar to an umbrella for the motor.)<\/p>\n\n\n\n
CAPACITOR<\/strong><\/h3>\n\n\n\n
A device that, when connected in an alternating-current circuit, causes the current to lead the voltage in the time phase. The peak of the current wave is reached ahead of the peak of the voltage wave. This is the result of the successive storage and discharge of electric energy used in 1 phase motors to start or in 3 phases for power factor correction.<\/p>\n\n\n\n
CAPACITOR MOTOR<\/strong><\/h3>\n\n\n\n
A single-phase induction motor with a main winding arranged for direct connection to the power source, and auxiliary winding connected in series with a capacitor. There are three types of capacitor motors: capacitor start, in which the capacitor phase is in the circuit only during starting, permanent-split capacitor, which has the same capacitor and capacitor phase in the circuit for both starting and running; two-value capacitor motor, in which there are different values of capacitance for starting and running.<\/p>\n\n\n\n
CAPACITOR START<\/strong><\/h3>\n\n\n\n
The capacitor start single-phase motor is basically the same as the split-phase start, except that it has a capacitor in series with the starting winding. The addition of the capacitor provides a more ideal phase relation and results in greater starting torque with much less power input. As in the case of the split-phase motor, this type can be reversed at rest, but not while running unless special starting and reversing switches are used. When properly equipped for reversing while running, the motor is much more suitable for this service than the split-phase start as it provides greater reversing ability at fewer watts input.<\/p>\n\n\n\n
CENTRIFUGAL CUTOUT SWITCH<\/strong><\/h3>\n\n\n\n
A centrifugally operated automatic mechanism used in conjunction with split-phase and other types of single-phase induction motors. Centrifugal cutout switches will open or disconnect the starting winding when the rotor has reached a pre-determined speed, and reconnect it when the motor speed falls below it. Without such a device, the starting winding would be susceptible to rapid overheating and subsequent burnout.<\/p>\n\n\n\n
CLUTCH<\/strong><\/h3>\n\n\n\n
A mechanical device for engaging and disengaging a motor often used when many starts and stops are required.<\/p>\n\n\n\n
CONDUCTOR<\/strong><\/h3>\n\n\n\n
A material, such as copper or aluminum, offers low resistance or opposition to the flow of electric current.<\/p>\n\n\n\n
CONDUIT BOX<\/a><\/strong><\/h3>\n\n\n\n
The metal container usually on the side of the motor where the stator (winding) leads are attached to leads going to the power supply.<\/p>\n\n\n\n
COGGING<\/strong><\/h3>\n\n\n\n
A term used to describe non-uniform angular velocity. It refers to rotation occurring in jerks or increments rather than smooth motion. When an armature coil enters the magnetic field produced by the field coils, it tends to speed up and slow down when leaving it. This effect becomes apparent at low speeds. The fewer the number of coils, the more noticeable it can be.<\/p>\n\n\n\n
COIL (Stator or Armature)<\/strong><\/h3>\n\n\n\n
The electrical conductors wound into the core slot, electrically insulated from the iron core. These coils are connected into circuits or windings which carry independent current. It is these coils that carry and produce the magnetic field when the current passes through them. There are two major types: “Mush” or “random” wound, round wire found in smaller and medium motors where coils are randomly laid in the slot of stator core; and formed coils of square wire individually laid in, one on top of the other, to give an evenly stacked layered appearance.<\/p>\n\n\n\n
COMMUTATOR<\/strong><\/h3>\n\n\n\n
A cylindrical device mounted on the armature shaft and consisting of a number of wedge-shaped copper segments arranged around the shaft (insulated from it and each other. The motor brushes ride on the periphery of the commutator and electrically connect and switch the armature coils to the power source.<\/p>\n\n\n\n
COMPOUND WOUND DC MOTORS<\/strong><\/h3>\n\n\n\n
Designed with both a series and shunt field winding, the compound motor is used where the primary load requirement is heavy starting torque, and adjustable speed is not required. (See Paralleling) Also used for parallel operation. The load must tolerate a speed variation from full-load to no-load.
Industrial machine applications include large planers, boring mills, punch presses, elevators, and small hoists.<\/p>\n\n\n\n
CONSTANT H.P.<\/strong><\/h3>\n\n\n\n
A designation for variable or adjustable speed motors used for loads requiring the same amount of H.P. regardless of their motor speed during normal operation.<\/p>\n\n\n\n
CONSTANT TORQUE<\/strong><\/h3>\n\n\n\n
Refers to loads whose H.P. requirements change linearly with changing speeds. Horsepower varies with the speed, i.e.- 2\/1 HP at 1800\/900 RPM. (Seen on some 2-speed motors). Possible applications include conveyors, some crushers, or constant-displacement pumps.<\/p>\n\n\n\n
CONSTANT SPEED<\/strong><\/h3>\n\n\n\n
A DC motor that changes speeds only slightly from a no-load to a full load condition. In AC motors, these are synchronous motors.<\/p>\n\n\n\n
CORE<\/strong><\/h3>\n\n\n\n
The iron portion of the stator and rotor; made up of cylindrical laminated electric steel. The stator and rotor cores are concentrically separated by an air gap, with the rotor core being the smaller of the two and inside to the stator core.<\/p>\n\n\n\n
COUNTER ELECTROMOTIVE FORCE(CEMF)<\/strong><\/h3>\n\n\n\n
The induced voltage in a motor armature, caused by conductors moving through or “cutting” field magnetic flux. This induced voltage opposes the armature current and tends to reduce it.<\/p>\n\n\n\n
COUPLINGS<\/strong><\/h3>\n\n\n\n
The mechanical connector joining the motor shaft to the equipment to be driven.<\/p>\n\n\n\n
CURRENT<\/strong><\/h3>\n\n\n\n
The time rate of flow of electrical charge and is measured in amps (amperes).<\/p>\n\n\n\n
CYCLES PER SECOND (HERTZ)<\/strong><\/h3>\n\n\n\n
One complete reverse of flow of alternating current per rate of time. (A measure of frequency.) 60 HZ (cycles per second) A.C. power is common throughout the U.S. and 50 HZ is more common in some foreign countries. <\/p>\n\n\n
<\/p>\n\n\n
D<\/strong><\/p>\n\n\n\n
“D” FLANGE<\/strong>
A special end shield with holes for through bolts in the flange and is primarily used for mounting the motor on gearboxes or bulkheads. Standardized for frames 143T through 445T. “D” flanges are not threaded and the bolt holes extend beyond the motor frame.

 
D.C. (DIRECT CURRENT)<\/strong>
A current that flows only in one direction in an electric circuit. It may be continuous or discontinuous and it may be constant or varying.

 
<\/a>DC MOTOR<\/a><\/strong>
A motor using either generated or rectified D.C. power (see Motor definition). A DC motor is usually used when variable speed operation is required.

 
DEFINITE PURPOSE MOTOR<\/strong>
A definite purpose motor is any motor design, listed and offered in standard ratings with standard operating characteristics with special mechanical features for use under service conditions other than usual or for use on a particular type of application. (NEMA)

 
DESIGN A, B, C, D – for AC MOTORS<\/strong>
NEMA has standard NEMA motor designs of various torque characteristics to meet the various requirements posed by different application loads. The design “B” is the most common design. (See chart for characteristics of each design.)

<\/p>\n\n\n\n
NEMA
DESIGN<\/strong><\/td>		STARTING
TORQUE<\/strong><\/td>		STARTING
CURRENT<\/strong><\/td>		BREAK-
DOWN
TORQUE<\/strong><\/td>		FULL
LOAD
SLIP<\/strong><\/td>		TYPICAL
APPLICATIONS<\/strong><\/td><\/tr>
A<\/td>Normal<\/td>High<\/td>High<\/td>Low<\/td>Mach. Tools, Fans<\/td><\/tr>
B<\/td>Normal<\/td>Normal<\/td>Normal<\/td>Normal<\/td>Same as Design “A”<\/td><\/tr>
C<\/td>High<\/td>Normal<\/td>Low<\/td>Normal<\/td>Loaded compressor
Loaded conveyor<\/td><\/tr>
D<\/td>Very high<\/td>Low<\/td>——-<\/td>High<\/td>High Punch Press<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

DIMENSIONS<\/strong>
NEMA has standard frame sizes and dimensions designating the height of the shaft, the distance between mounting bolt holes and various other measurements. The integral AC motor NEMA sizes run from 143T- 445T and the center of the shaft height in inches can be figured by taking the first two digits of the frame number and dividing it by 4.
The fractional horsepower motors, for which NEMA spells out dimensions, utilize 42, 48 and 56 frames whose shaft height in inches is figured by dividing the frame number by 16.

 
DRIP-PROOF GUARDED
A drip-proof machine with ventilating openings guarded (with screens) as in a guarded motor.

 
DRIP-PROOF MOTOR
An open motor in which the ventilating openings are so constructed that drops of liquid or solid particles falling on it, at any angle not greater than 15 degrees from the vertical, cannot enter either directly or by striking and running along a horizontal or inwardly inclined surface.

 
DUAL VOLTAGE
Some motors can operate on two different voltages, depending upon how it is built and connected. The voltages are either multiple of two or the three of one another.

 
DUAL TORQUE
Dual speed motor whose torque varies with speed (as the speed changes the horsepower remains constant).

 
DUTY CYCLE
The relationship between the operating and rest times or repeatable operation at different loads. A motor which can continue to operate within the temperature limits of its insulation system, after it has reached normal operating (equilibrium) temperature is considered to have a continuous duty (CONT.) rating. One which never reaches equilibrium temperature, but is permitted to cool down between operations is operating under intermittent duty (INT.) conditions such as a crane and hoist motor which is often rated 15 or 30 min. duty.

 
DYNAMOMETER<\/strong>
A device that loads the motor to measure output torque and speed accurately by providing a calibrated dynamic load. Helpful in testing motors for nameplate information and an effective device in measuring efficiency.<\/p>\n\n\n
<\/p>\n\n\n
E<\/strong><\/p>\n\n\n\n
EDDY CURRENT
<\/strong>Localized currents induced in an iron core by alternating magnetic flux. These currents translate into losses (heat) and their minimization is an important factor in lamination design.

 
EFFICIENCY
<\/strong>The efficiency of a motor is the ratio of mechanical output to electrical input. It represents the effectiveness with which the motor converts electrical energy into mechanical energy. NEMA has set up codes that correlate to specific nominal efficiencies. A decrease in losses (the elements keeping the motor from being 100% efficient of 10% constitutes an upward improvement of the motor of one code on the NEMA table. Each nominal efficiency has a corresponding minimum efficiency number.

 
ELECTRICAL DEGREE
A unit of measurement of time as applied to alternating current. One complete cycle =360 electrical degrees. One cycle in a rotating electric machine is accomplished when the rotating field moves from one pole to the next pole of the same polarity. There are 360 electrical degrees in this time period. Therefore, in a two-pole machine, there are 360 degrees in one revolution, and the electrical and mechanical degrees are equal. In a machine with more than two poles, the number of electrical degrees per revolution is obtained by multiplying the number of pairs of poles by 360.

 
ELECTRICAL UNBALANCE
In a 3 phase supply, where the voltages of the three different phases are not exactly the same. Measured in % of unbalance.

 
ELECTROMOTIVE FORCE (EMF)
A synonym for voltage, usually restricted to generated voltage.

 
ENCAPSULATED WINDING
A motor that has its winding structure completely coated with an insulating resin (such as epoxy). This construction type is designed for exposure to more severe atmospheric conditions than the normal varnished winding.

 
ENCLOSURES
<\/strong>The housing, frame, of the motor of which there are two broad classifications; open and totally closed. There are specific types of each:

 
MOTOR ENCLOSURES
<\/strong><\/p>\n\n\n\n
ODG – Open Drip-Proof, Guarded
ODG-FV – Open Drip-Proof, Force Ventilated
ODG-SV – Open Drip-Proof, Separately Ventilated
ODP – Open Drip-Proof
HP – Vertical P-Base, Average\/Normal Thrust
LP – Vertical P-Base, Medium Thrust, Extended Thrust
Prot. – Protected
TEAO – Totally-Enclosed, Air-Over
TEBC – Totally-Enclosed, Blower-Cooled
TECACA – Totally-Enclosed, Closed Circuit,, Air to Air
TEDC-A\/A – Totally-Enclosed, Dual Cooled, Air to Air
TEDC-A\/W – Totally-Enclosed, Dual Cooled, Air to Water
TEFC – Totally-Enclosed, Fan-Cooled
TENV – Totally-Enclosed Non-Ventilated
TETC – Totally-Enclosed, Tube Cooled
TEWAC – Totally-Enclosed, Water\/Air Cooled
TEXP – Totally-Enclosed, Explosion-Proof
IP-22 – Open Drip-Proof
IP-44 – Totally-Enclosed
IP-54 – Splash Proof
IP-55 – Washdown
WPI – Weather Protected, Type I
WPII – Weather Protected Type II
XE – Premium Efficient
XL – Extra Life
XP – Explosion-Proof
XT – Extra Tough
<\/p><\/blockquote>\n\n\n\n

ENDSHIELD
<\/strong>The part of the motor housing which supports the bearing and acts as a protective guard to the electrical and rotating parts inside the motor. This part is frequently called the “end bracket” or “end bell.”

 
EXPLOSION-PROOF ENCLOSURE<\/a>
<\/strong>A totally enclosed enclosure is constructed to withstand an explosion of a specified gas, vapor or dust which may occur within it. Should such an explosion occur, the enclosure will prevent the ignition or explosion of the gas or vapor which may surround the motor enclosure. These motors are listed with Underwriter’s Laboratories.

 
EXPLOSION-PROOF-HAZARDOUS LOCATIONS<\/strong>
DIVISION I – Location in which ignitable concentrations of flammable or combustible material exist and come in contact with the motor.
DIVISION 11 – Locations in which ignitable concentrations of flammable or combustible material exist but are contained within closed systems or containers and normally would not come in contact with the motor.
EXPLOSION-PROOF-U.L. CLASSIFICATIONS CLASS I -Those in which flammable gasses or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures.
Group C – Atmospheres containing ethyl or ether vapors.
Group D – Atmospheres containing gasoline, hexane, benzene, butane, propane, alcohols, acetone, benzol, lacquer solvent vapors, natural gas, etc.
Class 11-Those which are hazardous because of the presence of combustible dust.
Group E – Atmospheres containing metal dust, including aluminum, magnesium, or their commercial alloys.
Group F – Atmospheres containing carbon black, charcoal, coal or coke dust.
Group G – Atmospheres containing flour, starch, grain or combustible plastics or chemical dusts.

EXTERNALLY VENTILATED<\/strong>
A motor using an external cooling system. This is required in applications where the motor’s own fan will not provide sufficient cooling; this is true for certain duty cycle applications, slow-speed motors, also in environments with extreme dirt. Often a duct with an external blower is used to bring clean air into the motor’s air-intake.<\/p>\n\n\n
<\/p>\n\n\n
F<\/strong><\/p>\n\n\n\n
FIELD<\/strong>
A term commonly used to describe the stationary (Stator) member of a DC Motor. The field provides the magnetic field with which the mechanically rotating (Armature or Rotor) member interacts.<\/p>\n\n\n\n
FIELD WEAKENING<\/strong>
The introduction of resistance in series with the shunt wound field of a DC motor to reduce the voltage and current which weakens the strength of the magnetic field and thereby increases the motor speed.<\/p>\n\n\n\n
FLANGE<\/strong>
Mounting end shield with special rabbets and bolt holes for mounting such equipment as pumps and gearboxes to the motor or for overhanging the motor on the driven machine.<\/p>\n\n\n\n
FLUX<\/strong>
The magnetic field is established around an energized conductor or permanent magnet. The field is represented by flux lines creating a flux pattern between opposite poles. The density of the flux lines is a measure of the strength of the magnetic field.<\/p>\n\n\n\n
FORM FACTOR<\/a><\/strong>
A figure of merit which indicates how much rectified current departs from pure (non-pulsating) DC. A large departure from unity form factor (pure DC, expressed as 1.0) increases the heating effect of the motor and reduces brush life. Mathematically, the form factor is the ratio of the root-mean-square (RMS) value of the current to the average (av) current or Ir<\/sup>ms\/lav.<\/p>\n\n\n\n
FORM WOUND<\/strong>
A type of coil in which each winding is individually formed and placed into the stator slot. A cross-sectional view of the winding would be rectangular. Usually, form winding is used on high voltage, 2300 volts and above, and large motors (449T and above). Form winding allows for better insulation on high voltage than does random (mush) winding.<\/p>\n\n\n\n
FRACTIONAL-HORSEPOWER MOTOR<\/strong>
A motor usually built in a frame smaller than that having a continuous rating of one horsepower, open construction, at 1700 -1800 rpm. Within NEMA frame sizes FHP encompasses the 42, 48 and 56 frames. (In some cases the motor rating does exceed 1 HP, but the frame size categorizes the motor as a fractional.) The height in inches from the center of the shaft to the bottom of the base can be calculated by dividing the frame size by 16.<\/p>\n\n\n\n
FRAME<\/strong>
The supporting structure for the stator parts of an AC motor; in a DC motor, the frame usually forms a part of the magnetic coil. The frame also determines mounting dimensions (see frame size).<\/p>\n\n\n\n
FRAME SIZE<\/strong>
This refers to a set of physical dimensions of motors as established by NEMA. These dimensions include critical mounting dimensions. 48 and 56 frame motors are considered fractional horsepower sizes even though they can exceed 1 horsepower, 143T to 449T are considered integral horsepower AC motors and 5000 series and above are called large motors. <\/p>\n\n\n\n
FREQUENCY<\/strong>
The rate at which alternating current makes a complete cycle of reversals. It is expressed in cycles per second. In the U.S. 60 cycles (Hz) is the standard while in other countries 50 Hz (cycles) is more common. The frequency of the AC will affect the speed of a motor.<\/p>\n\n\n\n
FRONT END OF A MOTOR<\/strong>
The front end of a normal motor is the end opposite the coupling or driving pulley. (NEMA) This is sometimes called the opposite pulley end (O.P.E.) or commutator end (C.E.).<\/p>\n\n\n\n
FULL-LOAD CURRENT<\/strong>
The current flowing through the line when the motor is operating at full-load torque and full-load speed with rated frequency and voltage applied to the motor terminals.<\/p>\n\n\n\n
FULL-LOAD TORQUE<\/strong>
That torque of a motor necessary to produce its rated horsepower at full-load speed sometimes referred to as running torque. <\/p>\n\n\n
<\/p>\n\n\n
G<\/strong><\/p>\n\n\n\n
GEARHEAD<\/strong>
The portion of a gear motor which contains the actual gearing which converts the basic motor speed to the rated output speed.<\/p>\n\n\n\n
GEARMOTOR<\/strong>
A gearhead and motor combination to reduce the speed of the motor to obtain the desired RPM’s.<\/p>\n\n\n\n
GENERAL PURPOSE MOTOR<\/strong>
A general-purpose motor is any motor having a “B” design, listed and offered in standard ratings with standard operating characteristics and mechanical construction for use under usual service conditions without restriction to a particular application or type of application. (NEMA)<\/p>\n\n\n\n
GROUNDED MOTOR<\/strong>
A motor with an electrical connection between the motor frame and ground.<\/p>\n\n\n\n
GUARDED MOTOR<\/strong>
An open motor in which all openings giving direct access to live or rotating parts (except smooth shafts) are limited in size by the design of the structural parts or by screens, grills, expanded metal, etc., to prevent accidental contact with such parts. Such openings shall not permit the passage of a cylindrical rod 1\/2 inch in diameter. <\/p>\n\n\n
<\/p>\n\n\n
H<\/strong><\/p>\n\n\n\n
HEAT EXCHANGER
<\/strong>A device which will transfer the heat from inside the motor to another medium, through a radiator type heat exchanger.<\/p>\n\n\n\n
HERTZ (HZ)
<\/strong>One cycle per second (as in 60 Hz. which is 60 cycles per second).<\/p>\n\n\n\n
HORSEPOWER
<\/strong>The measure of the rate of work. One horsepower is equivalent to lifting 33,000 pounds to a height of one foot in one minute. The horsepower of a motor is expressed as a function of torque and rpm. For motors the following approximate formula may be used:
<\/p>\n\n\n\n
\"\"\/<\/figure>\n\n\n\n
where HP = horsepower, T = torque (in. lb.ft.), and RPM = revolutions per minute.<\/p>\n\n\n\n
HMI<\/a>
<\/strong>Otherwise known as a Human Machine Interface,   an HMI is an operator interface terminal that connects a person to a system, machine, or device.  It can be used to monitor inputs and outputs, track production trends, display data, and to oversee key performance indicators (KPIs). <\/p>\n\n\n\n
HYSTERESIS LOSS
<\/strong>The resistance offered by materials to becoming magnetized (magnetic orientation of molecular structure) results in energy being expended and corresponding loss. Hysteresis loss in a magnetic circuit is the energy expended to magnetize and demagnetize the core. <\/p>\n\n\n
<\/p>\n\n\n
I<\/strong><\/p>\n\n\n\n
IDENTIFICATION
<\/strong>In most instances, the following information will help identify a motor:

1. Frame designation (actual frame size in which the motor is built)
2. Horsepower, speed, design, and enclosure.
3. Voltage, frequency, and a number of phases of power supply.
4. Class of insulation and time rating.
5. Application


INDUCTANCE<\/strong>
The characteristic of an electric circuit by which varying current in it produces a varying magnetic field which causes voltages in the same circuit or in a nearby circuit.

 
INDUCTION MOTOR<\/strong>
An induction motor is an alternating current motor in which the primary winding on one member (usually the stator) is connected to the power source and a secondary winding or a squirrel-cage secondary winding on the other member (usually the rotor) carries the induced current. There is no physical electrical connection to the secondary winding, its current is induced.

 
INERTIAL LOAD<\/strong>
A load (flywheel, fan, etc.) which tends to cause the motor shaft to continue to rotate after the power has been removed (stored kinetic energy). If this continued rotation cannot be tolerated, some mechanical or electrical braking means must normally be applied. This application may require a special motor due to the energy required to accelerate the inertia. Inertia is measured in either lb.ft.2 or OZ.jn.2
Inertia reflected the shaft of the motor = (Load RPM) 2\/Motor RPM


INSULATOR<\/strong>
A material which tends to resist the flow of electric current (paper, glass, etc.) In a motor the insulation serves two basic functions:

1. Separates the various electrical components from one another.
2. It protects itself and the electrical components from the attack of contaminants and other destructive forces.


INSULATION<\/strong><\/a> SYSTEMS
<\/strong>Five specialized elements are used, which together constitute the motor’s INSULATION SYSTEM. The following are typical in an AC motor:

1. TURN-TO-TURN INSULATION between separate wires in each coil. (Usually enamel on random wound coils of smaller motors – tape on “form wound” coils of larger motors.)
2. PHASE-TO-PHASE INSULATION between adjacent coils in different phase groups. (A separate sheet material on smaller motors – not required on form wound coils because the tape also performs this function.)
3. PHASE-TO-GROUND INSULATION between windings as a whole and the “ground” or metal part of the motor. (A sheet material, such as the liner used in stator slots, provides both di-electric and mechanical protection.)
4. SLOT WEDGE to hold conductors firmly in the slot.
5. IMPREGNATION to bind all the other components together and fill in the air spaces. (A total impregnation, applied in a fluid form and hardened, provides protection against contaminants.


INSULATION CLASS
<\/strong>Since there are various ambient temperature conditions a motor might see and different temperature ranges within which motors run and insulation is sensitive to temperature; motor insulation is classified by the temperature ranges at which it can operate for a sustained period of time.

There are four common classes:<\/p>\n\n\n\n
Class<\/td>AC Motor DC. Motor W\/1.00 S.F.
Max. Total Temperature Range
(Including Ambient and Temperature
110\u0192 Hot Spot) Range<\/td>		 <\/td>DC Motor Total
Temperature Range<\/td><\/tr>
A<\/td>105\u0192C<\/td>A<\/td>110\u0192 C<\/td><\/tr>
B<\/td>130\u0192C<\/td>B<\/td>140\u0192 C<\/td><\/tr>
F<\/td>155\u0192C<\/td>F<\/td>170\u0192 C<\/td><\/tr>
H<\/td>180\u0192C<\/td>H<\/td>195\u0192 C<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
When a motor insulation class is labeled on the nameplate the total insulation system is capable of sustained operation at the above temperature.

 
INTERMITTENT DUTY
<\/strong>A requirement of service that demands operation for alternate intervals of (1 ) load and no-load; or (2) load and rest; or (3) load, no-load and rest; such alternate intervals being definitely specified.

 
INTERPOLES<\/strong>
An auxiliary set of field poles carrying armature current to reduce the field flux caused by armature reaction in a DC motor.

 
INVERTER<\/a><\/strong>
An electronic device that converts fixed frequency and fixed voltages to variable frequency and voltage. Enables the user to electrically vary the speed of an AC motor.

 
I2R<\/strong>
Losses due to the current flowing in a conductor caused by resistance (equals the current squared times the resistance.)<\/p>\n\n\n
<\/p>\n\n\n
J<\/strong><\/p>\n\n\n\n
J SECONDS (DC Motors)
<\/strong>“J” is the per-unit moment of inertia. It is defined as the time in seconds to accelerate the motor armature to-rated base speed using rated full load torque.
<\/p>\n\n\n\n
J =<\/td>WR2<\/sup>x Base Rpm(seconds)<\/td><\/tr>
 <\/td>—————————-<\/td><\/tr>
 <\/td>308 x Rated Torque<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

 
JACKSCREW
<\/strong>A device used for leveling the positioning of a motor. These devices are adjustable screws fitting on the base or motor frame. Also a device for removing end shields from a motor assembly.<\/p>\n\n\n
<\/p>\n\n\n
K<\/strong><\/p>\n\n\n\n
KILOWATT
<\/strong>Since the watt is a relatively small unit of power, the kilowatt (kW), 1,000 watts, is used where larger units of power measurements are desirable. <\/p>\n\n\n
<\/p>\n\n\n
L<\/strong><\/p>\n\n\n\n
LAMINATIONS<\/strong>
The steel portion of the rotor and stator cores made up of a series of thin laminations (sheets) that are stacked and fastened together by cleats, rivets or welds. Laminations are used instead of a solid piece in order to reduce eddy-current losses.<\/p>\n\n\n\n
LARGE MOTORS<\/strong>
Usually refers to AC motors in 5,000 series frames and above and to 500 series frames and larger in DC.<\/p>\n\n\n\n
LOAD<\/strong>
The burden imposed on a motor by the driven machine. It is often stated as the torque required to overcome the resistance of the machine it drives. Sometimes “load” is synonymous with “required power.”<\/p>\n\n\n\n
LOCKED ROTOR CURRENT<\/strong><\/a>
Steady-state current is taken from the line with the rotor at standstill (at rated voltage and frequency). This is the current seen when starting the motor and load.<\/p>\n\n\n\n
LOCKED ROTOR TORQUE<\/strong>
The minimum torque that a motor will develop at rest for all angular positions of the rotor (with rated voltage applied at a rated frequency).<\/p>\n\n\n\n
LOSSES<\/strong>
A motor converts electrical energy into mechanical energy and in so doing, encounters losses. These losses are all the energy that is put into a motor and not transformed into usable power but are converted into heat causing the temperature of the windings and other motor parts to rise.<\/p>\n\n\n\n
LUBRICATION<\/strong>
In order to reduce wear and avoid overheating certain motor components require lubricating (application of an oil or grease). The bearings are the major motor component requiring lubrication (as per manufacturer’s instructions). Excess greasing can, however, damage the windings and internal switches, etc. (See PLS<\/a>) <\/p>\n\n\n
<\/p>\n\n\n
M<\/strong><\/p>\n\n\n\n
MAGNETIC POLARITY<\/strong>
It is a fundamental principle of a 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.<\/p>\n\n\n\n
MEDIUM MOTORS<\/strong>
Motors in NEMA 143T to 449T frames.<\/p>\n\n\n\n
MEGGER TEST<\/strong><\/a>
A measure of 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.<\/p>\n\n\n\n
MOTOR<\/strong><\/a>
A device that takes electrical energy and converts it into mechanical energy to turn a shaft.<\/p>\n\n\n\n
MULTI-SPEED MOTORS<\/strong>
A motor wound in such a way that varying connections at the starter can change the speed to a predetermined speed. The most common multi-speed motor is a two speed although three- and four-speeds are sometimes available. Multi-speed motors can be wound with two sets of windings or one winding. They are also available either constant torque, variable torque or constant horsepower. <\/p>\n\n\n
<\/p>\n\n\n
N<\/strong><\/p>\n\n\n\n
NAMEPLATE<\/strong>
The plate on the outside of the motor describing the motor, HP, voltage, RPM’s, efficiency, design, enclosure, etc.

 
NAVY SERVICE “A”<\/strong>
Motors designed to meet requirements of MIL M-17059 or MlL M-17060 for high shock and service and are essential to the combat effectiveness of a ship. These motors are usually made of nodular iron.

 
N.E.C. TEMPERATURE CODE (‘T’ CODE)<\/strong>
<\/a>An index for describing maximum allowable “skin” (surface) temperature of a motor under any normal or abnormal operating conditions. The “T” codes are applicable to U.L. Listed explosion-proof motors. The skin temperature shall not exceed the minimum ignition temperature of the substances to be found in a hazardous location. The “T” code designations apply to motors and other types of electrical equipment subject to hazardous location classification.

 
SKIN TEMPERATURE<\/strong> IDENTIFICATION NUMBERS<\/strong><\/p>\n\n\n\n
Maximum Surface<\/th>Degrees F<\/th>T-Codes ID
Numbers<\/th>		U\/L Requirement
for Class & Group<\/th><\/tr>
450<\/td>842<\/td>T1<\/td><\/td><\/tr>
300<\/td>572<\/td>T2<\/td><\/td><\/tr>
280<\/td>536<\/td>T2A<\/td>Class I Group D w\/Cautionary Label<\/td><\/tr>
260<\/td>500<\/td>T2B<\/td><\/td><\/tr>
230<\/td>446<\/td>T2C<\/td><\/td><\/tr>
215<\/td>419<\/td>T2D<\/td>Class I Group D<\/td><\/tr>
200<\/td>392<\/td>T3<\/td>Class ll Group E & F<\/td><\/tr>
180<\/td>356<\/td>T3A<\/td>Class I Group C w\/Cautionary Label<\/td><\/tr>
165<\/td>329<\/td>T3B<\/td>Class ll Group G<\/td><\/tr>
160<\/td>320<\/td>T3C<\/td>Class I Group C<\/td><\/tr>
135<\/td>275<\/td>T4<\/td><\/td><\/tr>
120<\/td>248<\/td>T4A<\/td><\/td><\/tr>
100<\/td>212<\/td>T5<\/td><\/td><\/tr>
85<\/td>185<\/td>T6<\/td><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n


NEMA<\/strong>
The National Electrical Manufacturers Association (http:\/\/www.nema.org) is a non-profit organization organized and supported by manufacturers of electric equipment and supplies. NEMA has set standards on:
<\/p>\n\n\n\n