 CONTENTS
1. ELECTRIC CONTROL
TERMINOLOGY
2. MOTOR SELECTION
GUIDES
3. ABBREVIATIONS USED
IN MOTOR LISTINGS
4. ELECTRIC MOTOR
TERMINOLOGY
5. LIQUID PUMP TERMINOLOGY
ELECTRIC CONTROL
TERMINOLOGY
Hysteresis (Dead Band) The
gap between the point at which the output relay is turned off
(upon rising temp.) and the point at which the output relay is
turned on (upon falling
temp).
J (IC) Thermocouples Have
a normal operating range of 0 to 840 degrees F. These
types of items are relatively inexpensive and can rust in oxidized
and steam atmospheres.
Offset A deviation below
the set temperature a "PD" controller will allow when
a steady
state temperature is reached. It is due to temperature loss of
the system.
On-Off Control Action When
the temperature being measured falls below the set point, the
output relay in the controller turns on. The output relay turns
off when the temperature rises higher than the set point. Application:
On-Off action is best for systems where temperature rises slowly
and the difference between the temperature when output relay
is on and when the output relay is off is small.
Proportional (P) Control Action
When the temperature is outside of proportional band (a range
with a top and bottom limit) the output relay in the controller
turns on. When the temperature is within the proportional band,
the output relay is on for a period of time proportional to the
amount the temperature is below the set point in relation to
the "width" of the proportional band. The minimum output
is 50%. Application: Proportional control action allows for applications
where adherence to a set point is important.
Proportional Period Time
needed for an on/off cycle of a "PD" controller.
Rate (D) or Derivative Control Action
Used with proportional (P) control action. It allows
a quick response to a temperature that deviated quickly from
the set point.
MOTOR SELECTION
GUIDES
1. Power Supply Single-phase
power is the most readily available power supply.
Single-phase motors of correct voltage can operate from a three-phase
system when properly connected to any one of the three phases.
However, three-phase motors cannot be connected to single phase
power. A three-phase motor is less expensive and more durable
than the same size single-phase motor, but the extra cost of
installing three-phase lines must be considered.
2. Motor Type The economical
split-phase motor is a good choice where starting load is light
(belt driven fans and blowers) or where load is not applied until
operating speed is
reached (table saws and drill presses). Shaded pole and permanent
split capacitor motors are normally designed for direct-drive
fans and blowers. Capacitor-start motors are for
conveyors, air compressors and other devices where heavy loads
must be started.
Three-phase motors are used for high starting torque applications
where three-phase power is available.
3. Motor HP and Speed Check
nameplate data if replacing old motor. On new
equipment, your dealer can recommend the proper motor. In general,
both motor price and physical size increase as HP increases and
Rpm decreases.
4. Bearings Sleeve bearing
motors are used where moderate loads are encountered. They can
be mounted in any position and are quieter and less expensive
than ball bearing motors. Ball bearing motors are recommended
for powering devices which create heavy loads and/or are located
in a damp, dirty environment.
5. Voltage Motor rating must
match voltage and frequency (Hertz) of electricity
supplied.
6. Enclosure Open drip proof
motors are designed for use in areas that are fairly dry,
clean and well ventilated. If installed outside, motor must be
protected with a cover that
does not restrict air flow. Wet or dirty conditions require totally
enclosed, fan-cooled
construction. Explosive conditions, no matter how slight, require
an explosion proof
(hazardous location) motor. Be sure class and group rating(s)
of motor conform to that
required by the particular hazardous location.
7. Shaft and Mounting Dimensions Select
NEMA frame size or non-NEMA motor with proper dimensions to match
or new applications
8. Thermal Protection Use
a thermally protected motor or a motor starter incorporating
thermal overload relays to protect against overheating due to
failure-to-start or overloading. Especially on motors that start
automatically, are located remotely, unattended, or out-of-sight
of operator. This protection may be a motor starter complying
with Article 430 of the National Electrical Code, a motor incorporating
integral thermal protection (a thermally protected motor), or
an impedance protected motor.
For fractional horsepower motors, one with integral thermal
protection (protector built-in) is more cost effective and simpler
to install. For integral horsepower motors, a motor starter should
always be used.
Motors with automatic reset thermal protection MUST NOT be
used where automatic or
unexpected starting of a motor could be hazardous. Where a hazard
exists, always use a
manual-reset thermally protected motor. Applications where automatic
restarting could be
hazardous include compressors, conveyors, power tools, farm equipment,
some fans and
blowers.
9. Run Capacitors for PSC Motors Capacitor
ratings to HP ratings vary between
different brands and applications. Capacitor value and performance
is essential to proper
motor operation. To ensure maximum performance and motor life,
always use the correct
capacitor as specified on the motor nameplate.
ABBREVIATIONS
USED IN MOTOR LISTINGS
AC Alternating Current Max
Maximum
Amb Ambient Mfd Microfarad
Amps Amperes Min Minimum
Auto Automatic Mtg Mounting
AWG American Wire Gauge NEC
National Electrical Code
C Centigrade NEMA N.E. Manufacture's
Assoc.
Cap Capacitor No Number
CCW Counterclockwise Nom Nominal
Cond Conductor OC On Center
CSA Canadian Standards Association
OPAO Open, Air Over
CW Clockwise Prot Protection
DC Direct Current PSC Permanent
Split Capacitor
Dia Diameter Resil Resilient
Encl Enclosure Rev Reversible
F/L Full-Load RPM Revolutions
per Minute
Ft-Lb Foot-Pound Shpg Shipping
H, Ht Height Slv Sleeve
HP Horsepower Spd Speed
Hz Hertz Syn Synchronous
Imp Impedance TEAO Totally Enclosed,
Air Over
In Inch,
Inches TEFC Totally Enclosed Fan Cooled
In-Lb Inch-Pound TENV Totally
Enclosed Non Ventilated
L, Lgth
Length, Long UL Underwriters Laboratories, Inc.
Lbs Pounds
V Volts,
Voltage
Man Manual
W Width, Watts
ELECTRIC MOTOR
TERMINOLOGY
Ambient (Amb) The temperature
of the space around the motor. Most motors are
designed to operate in an ambient not over 40ºC (104Fº).
Note: A rating of 40ºC Ambient is not the same as a rating
of 40ºC Rise; see Temperature Rise.
Air-Over Motors intended for
fan and blower service. Must be located in the air stream
to provide motor cooling.
Efficiency The ratio of output
power divided by input power; usually expressed as a
percentage. A measure of how well the electrical energy input
to a motor is converted into
mechanical energy at the output shaft. The higher the efficiency,
the better the conversion
process and lower the operating costs.
Enclosure (Encl) The motors
housing.
Types:
Drip proof (DP) Ventilation openings in the end shields
and shell placed so drops of liquid falling within an angle of
15º from vertical will not affect performance. Usually used
indoors, in fairly clean locations.
Totally Enclosed (TE) No ventilation
openings in motor housing (but not air tight). Used in locations
which are dirty, damp, oily, etc.
Totally Enclosed, Fan Cooled (TE FC)
includes an internal fan, in a protective shroud, to blow cooling
air over the motor.
Totally Enclosed, Non ventilated (TENV)
Not equipped with an external cooling fan. Depends on convection
air for cooling.
Totally Enclosed, Air Over (TEAO)
Air flow from driven device provides cooling.
Explosion Proof (EX PRF) A totally
enclosed motor designed to withstand an internal explosion of
specified gases or vapors, and not allow the internal flame or
explosion to escape. See Ex.-Prf. motors for classifications.
Full-Load Amps (F/L Amps) Line
Current (amperage) drawn by a motor when operating at rated load
and voltage. Shown on motor name plate. Important for proper
wire size selection and motor starter heater selection.
Frame Usually refers to the
NEMA system of standardized motor mounting dimensions,
which facilitates replacement.
Bearings (Brgs)
Basic Types:
Sleeve (Slv) Preferred where low noise level is important,
as on fan and blower motors. Unless otherwise stated, sleeve
bearing motors listed herein can be mounted in any position,
including shaft-up or shaft-down (all position mounting).Ball
Used where higher load capacity is required or periodic lubrication
is impractical. Two means used to keep out dirt: Shields Metal
rings with close running clearance on one side (single-shielded)
or both sides (double-shielded) of bearing. Seals Similar to
shields, except have rubber lips that press against inner race,
more effectively excluding dirt, etc.
Unit Motors are constructed
with a long, single sleeve bearing. For fan duty only.
All-position mounting unless otherwise stated.
Hertz (Hz) Frequency, in cycles
per second, of AC power; usually 60Hz in USA, 50 Hz overseas.
(Abbreviated Cps or Cy in the past).
Insulation (Ins) In motors,
usually classified by maximum allowable operating
temperatures: Class A-105ºC (221ºF), Class B-130ºC
(266ºF), Class F-155ºC (311ºF), Class H-180ºC
(356ºF).
Motor Speeds:
Synchronous The theoretical maximum speed at which
an induction-type motor can
operate. Synchronous speed is determined by the power line frequency
and motor design
(number of poles), and calculated by formula. Frequency in Hz
x 120
Syn. RPM = No. of Poles
Full-Load The nominal speed
at which an induction type motor operates under rated input and
load conditions. This will always be less than the synchronous
speed and will vary depending on the rating and characteristics
of the particular motor. For example, four pole 60 Hz fractional
horsepower motors have a synchronous speed of 1800 rpm, a nominal
full load speed (as shown on the nameplate) of 1725 rpm, and
an actual full load speed ranging from 1715 to 1745 rpm.
Motor Types: Classified by
operating characteristics and/or type of power required;
Induction Motors for AC Operation Most common type. Speed remains
relatively
constant as load changes.
There are several Types:
Single Phase Available in these types:
Shaded Pole Low starting torque, low cost. Usually
used in direct-drive fans and
blowers, and in small gear motors.
Permanent Split Capacitor (PSC)
Performance and applications similar to shaded
pole but more efficient, with lower line current and higher horsepower
capabilities.
Split-Phase Start, Induction run (or simply
split phase) Moderate starting torque, high break-down
torque. Used on easy-starting equipment, such as belt driven
fans and blowers, grinders, centrifugal pumps, gear motors, etc.
Split-Phase Start Capacitor Run
Same performance as induction run, except higher efficiency.
Often used on Wattrimmer® fan blower motors.
Capacitor-Start, Induction Run (or simply,
capacitor start or capacitor) High starting and break-down
torque, medium starting current. Used on hard-starting applications
such as compressors, positive disposal pumps, farm equipment,
etc.
Capacitor Start, Capacitor Run Similar to capacitor-start, induction-run,
except
have higher efficiency. Generally used in higher HP single phase
ratings.
Three Phase Operate on 3-phase
power only. High starting and breakdown torque, high efficiency,
medium starting current, simple, rugged design, long life. For
industrial uses.
Direct Current (DC) Usable
only if DC available and in adjustable-speed applications.
AC/DC (AC series or Universal)
Operate on AC (60 or 50Hz) or DC power. High
speed, usually 5000 RPM or more. Brush type. Speed drops rapidly
as load increases.
Useful for drills, saws, etc., where high output and small size
are desired and speed
characteristic and limited life (primarily of brushes) is acceptable.
Mounting (Mtg):
Basic Types:
Rigid Motor Solidly fastened to equipment through
metal base that is bolted or
welded to motor shell.
Resilient (Res) Sometimes
called rubber or rbr.-motor shell isolated from base by
vibration absorbing material, such as rubber rings on the end
shields, to reduce transmission of vibration to the driven equipment.
Face or Flange Shaft end
has a flat mounting surface, machined to standard
dimensions, with holes to allow easy, secure mounting to driven
equipment. Commonly used on jet pumps, oil burners and gear reducers.
Stud Motor has bolts extending
from front or rear, by which it is mounted. Often
used on small, direct drive fans and blowers.
Yoke Tabs or ears are welded
to motor shell, to allow bolting motor to a fan column
or bracket.
Power The energy used to
do work. Also the rate at which work is done. Measured in
watts, horsepower, etc.
Power Factor The ratio of
real power (watts) divided by apparent power (volt-amperes).
Do not confuse power factor with efficiency. A measure of the
extent to which power transmission or distribution systems are
utilized.
Rotation (Rot) Direction
in which shaft rotates: CW = clockwise; CCW = counter
clockwise; Rec = reversible, rotation can be changed. Unless
stated otherwise, rotation
specified is as viewed facing shaft end of motor.
Service Factor (SF, Svc Fctr)
A measure of the reserve margin built into a motor.
Motors rated over 1.0 SF have more than normal margin, and are
used where unusual
conditions such as occasional high or low voltage, momentary
overloads, etc. are likely to
occur.
Severe Duty A totally enclosed
motor with extra protection (shaft slinger, gasketed
terminal box) to resist entry of contaminants. Used in extra
dirty, wet or other contaminated environments.
Temperature Rise The amount
by which a motor, operating under rated conditions, is
hotter than its surroundings. On most motors, manufacturers have
replaced Rise rating on
the motor nameplate with a listing of the ambient temperature
rating, insulation class and
service factor.
Thermal protector A temperature
sensing device built into the motor that disconnects
the motor from its power source if the temperature becomes excessive
due to failure-to-start or overloading. Especially important
for motors that start automatically, are located remotely, unattended,
or out-of-sight of operator.
Basic Types; Automatic-Reset (Auto) After motor cools, thermal
protector automatically restores power. Should not be used where
unexpected restarting would be hazardous.
Manual-Reset (Man) An external
button must be pushed to restore power to motor.
Preferred where unexpected restarting would be hazardous, as
on saws, conveyors,
compressors, etc.
Impedance (Imp) or Impedance
Protected Motor is designed so that it will not
burn out in less than 15 days under locked rotor (stalled) conditions,
in accordance with UL standard, No. 519.
Torque Twist, or turning
ability, as applied to a shaft. Measured in foot-pounds (ft-lbs),
inch-pounds (in-lbs), ounce-feet (oz-ft) or ounce-inches (oz-in).
In motors the torque values are: Locked Rotor Torque, or Starting
Torque The torque produced at initial start.
Breakdown Torque The maximum
torque a motor will produce while running,
without an abrupt drop in speed and power.
Voltage The pressure in an
electrical system. The force pushing the electric current
through the circuit, like pressure in a water system.
LIQUID PUMP
TERMINOLOGY
Flow The measure of the liquid
volume capacity of a pump. Given in gallons per hour
(GPH) or gallons pre minute (GPM). To convert GPH to GPM, divide
by 60.
Pressure The force exerted
on the walls of a container (tank, pipe, etc.) by the liquid.
Measured in pounds per square inch (PSI).
Head Another measure of pressure;
expressed in feet. Usually applies to centrifugal
pumps. Indicates the height of a column of water being lifted
by the pump, neglecting
friction losses in piping. For water, divide head in feet by
2.31 to get pressure in pounds per sq. inch (PSI).
Flooded Suction Liquid source
is higher than pump, and liquid flows to the pump by
gravity. Preferable for centrifugal pump installations.
Lift (Suction Lift) Liquid
source is lower than the pump. Pumping action creates a
partial vacuum and atmospheric pressure forces liquid up to the
pump. Theoretical limit of
suction lift is 34 feet; practical limit is 25 feet or less,
depending on pump type and elevation above sea level.
Static Discharge Head Vertical
distance (in feet) from pump to point of discharge.
Total Head The sum of discharge
head, suction lift and friction losses.
Prime A charge of liquid
required to begin pumping action of centrifugal pumps when
liquid source is lower than pump. May be held in pump by a foot
valve on the intake line or a valve or chamber within the pump.
Specific Gravity The ratio
of the weight of a given volume of liquid to the same volume
of pure water. Unless stated otherwise, power requirements of
all pumps are based on
pumping water. Pumping heavier liquids (specific gravity greater
than 1.0) will require more horsepower.
Viscosity The "thickness"
of a liquid, or, its ability to flow. Temperature must be stated
when specifying viscosity, since most liquids flow more easily
as they get warmer. The more viscous the liquid, the slower the
pump speed required.
Seal A device mounted in
the pump housing and/or on the pump shaft, to prevent
leakage of liquid from the pump.
Two Types:
Mechanical Has a rotating part and a stationary part
with highly polished touching
surfaces. Has excellent sealing capability and life, but can
be damaged by dirt or grit in the
liquid.
Lip A flexible ring (usually
rubber or similar material), with the inner edge held
closely against the rotating shaft by a spring.
Seal-Less (Magnetic Drive)
No seal is used; power is transmitted from motor to pump impeller
by magnetic force, through a wall that completely separates motor
from impeller.
Relief Valve Usually used
at the discharge of a positive displacement pump. An
adjustable, spring-loaded valve opens, or "relieves,"
when a preset pressure is reached. Used to prevent excessive
pressure and pump or motor damage if discharge line is closed
off.
Unloader Valve Similar to
relief valve, but not adjustable.
Check Valve Allows liquid
to flow in one direction only. Generally used in discharge line
to prevent reverse flow.
Foot Valve A type of check
valve with a built-in strainer. Used at point of liquid intake
to retain liquid in system, preventing loss of prime when liquid
source is lower than pump.
Centrifugal Pump A fan-shaped
impeller rotating in a circular housing, pushing liquid
towards a discharge opening. Simple design; only wearing parts
are the shaft seal and
bearings (if so equipped). Usually used where a large flow of
liquid at relatively low pressure (head, lift) is desired. Self-priming
centrifugals have same features as straight centrifugals but
will self prime without a foot valve to lifts indicated for the
particular model after an initial filling of the pump casing.
Non-self-priming centrifugals work best with the liquid source
higher than the pump (flooded suction/gravity feed). As the discharge
pressure (head) increases, flow and drive power requirements
decrease. Maximum flow and motor loading occur at minimum head.
Positive Displacement Pump Pumping
action created by moving chambers or pistons. The flow rate of
this pump is almost the same at any pressure level. Generally
self-priming. Should never be operated dry, because of internal
wearing of rubber parts. As discharge flow is restricted (higher
pressure or head) drive horsepower requirement increase. A relief
device should be provided on the discharge line to prevent over
pressure and damage to pump or motor if discharge line is closed
off or severely restricted.
The most common positive displacement
pump types are:
Diaphragm Consists of a flexible diaphragm which moves
up and down in a
chamber, creating suction and pressure. As the diaphragm is moved
up, it creates a vacuum which opens the suction valve and draws
fluid into the chamber. When the diaphragm is forced down, fluid
is forced out through the discharge valve. Diaphragm pumps handle
fluid mixtures with a much greater percentage of solids (e.g.,
silt, mud, sludge and waste).
Gear Consisting of two meshed
spur gears in a housing. As gears rotate, fluid is
carried in the space between the teeth. Will not handle abrasives
because of close running
tolerances of gears. For pressures to 100 psi. Suited for pumping
more viscous liquids, at
slower speeds.
Flexible Impeller A flexible,
vaned member, usually rubber, rotating in an eccentric
housing. The volume of the spaces between the vanes changes as
the pump rotates, creating pumping action. For pressures up to
30 PSI.
Rotary Screw A screw -shaped
rotor, turning within a flexible stator, usually of
rubber. Progressing cavities between screw and stator carry the
fluid. For pressures up to 75 PSI. Can handle abrasive mixtures
or slurries, at slower speeds.
Roller or Vane Rollers or
vanes in a rotor, rotating in an eccentric housing like a
flexible impeller pump. For pressures up to 200 PSI.
Piston Fluid is drawn in
and forced out by pistons moving within cylinders. Used
where pressures up to 500 PSI are required.
Jet Pump A type of centrifugal
pump utilizing water flow through a narrow opening or
nozzle (jet, ejector) to bring water from a well. As water is
forced through the nozzle, an
area of low pressure is created, and atmospheric pressure forces
additional water from the well into the system. In shallow well
systems (up to 25ft. lift), the jet is located at the pump. In
deep well systems, it is located at the bottom of the well.
Deep Well Submersible Pump
A centrifugal pump in which a number of impeller
assemblies, in a housing, are mounted on a shaft directly coupled
to a submersible motor.
Entire assembly is located at the bottom of the well. Power is
brought to the motor by a
waterproof cable.
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