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FDI 9806 for pdfs (Page 49)
48
GLOSSARY
Air over
- Motors intended for fan and blower service.
Motor must be located in the air stream to provide motor
cooling.
AC
- Abbreviation for alternating current. The current
flow in the circuit alternates back and forth continuously.
It does this 60 times per second with 60 Hz power.
Amps
- The amount of electrical current flowing in an
electrical circuit.
Ambient Temperature
- The air temperature surrounding
the motor.
Blast Cooled
- A term used to describe a motor having an
external fan and cooling case that forces cooling air over
the motor. Similar to totally enclosed fan cooled.
Bonderize
- A process in which zinc phosphate is applied
to the motor shaft to help the shaft resist corrosion.
BTU
- An abbreviation for British Thermal Unit. 12,000
BTUs equals 1 ton air conditioning.
CSA
- An abbreviation for Canadian Standards
Association. They set safety standards for motors and
electrical equipment used in Canada. All Fasco 60 hertz
motors meet CSA standards and display the CSA logo on
the nameplate.
CFM
- Abbreviation for Cubic Feet per Minute of air
which the fan or blower is moving.
Continuity
- A term used to describe a circuit that is com-
plete. That is, the circuit is able to pass electric current.
Cooling Degree Days
- Each degree that the average tem-
perature is above 65 degrees F produces one cooling
degree day.
CW/CCW
- Abbreviation for Clockwise/Counter-Clockwise
rotation. CWSE means Clockwise rotation viewing the
motor from the Shaft End. CWLE means Clockwise rotation
when viewing the motor from the Lead End.
Cycling (tripping)
- Motor overload is interrupting power to
motor due to excessive heat rise. It then turns the motor back
on when the motor cools. Condition repeats continuously.
DC
- An abbreviation for direct current. Current flows in
one direction through the circuit. 49
Efficiency
- The ratio or comparison of power output to
power input.
End Bell / End Shield
- The plates at each end of the
motor which support the bearings.
End Play
- This term refers to the in and out movement
the rotor has in the motor. Excessive end play can result
in problems such as fan blades hitting the fan guards. No
end play can result in a tight motor.
Fractional Horsepower
- Horsepower less than 1.
Frame or Frame Size
- A designation that controls certain
specifications that a motor will be built to if it is to be
called a particular frame size. Specifications such as
motor diameter are controlled.
Free Air
- The blower or fan blade operates at free air
when there are no effective restrictions to air flow at the
outlet or inlet.
Full Load Torque
- This is the amount of torque produced
by a motor when it is running a full load speed at rated
horsepower.
Full Load Amps
- Amperage drawn by a motor when
operating at rated load, voltage, and frequency.
General Purpose Motor
- It is designed with standard oper-
ating characteristics and mechanical construction for use
under usual service conditions. Has a service factor rating.
Grounding
- The connection of a motor to an earth
ground to reduce the possibility of electrical shock.
Heating Degree Days
- Each degree that the average tem-
perature is below 65 degrees F produces one heating
degree day.
Hertz
- Frequency in cycles per second of an AC power
supply. The U.S. operates on 60 hertz (HZ).
Hi Pot (High Potential)
- This is a motor test used to
detect conditions where electrical conductors (IE lead
wires, magnet wire) may have come in contact with the
non-electrical parts of the motor (IE stator laminations,
shell).
Horsepower
- The rating of a motors ability to do work.
HP = watts output / 746.
HP = (RPM x Torque in ounce-inches) / 1,000,000.
One HP = 746 watts. 50
GLOSSARY
HVAC
- An abbreviation for heating, ventilation, and air
conditioning.
Inch-Ounce
- A measure of torque (twist). One-inch
ounce is equal to one ounce of force applied 1" out away
from center line of the shaft.
Insulation Classes
- Insulation in a motor is rated by its
temperature capability for providing reasonable motor
life. The two most common are Class A - 105 degrees C,
Class B - 130 degrees C. These are total temperatures,
not temperature rises over ambient.
Integral
- Whole number. Used to describe horsepowers
of motors over one horsepower.
Lead
- The hook-up wire brought out from the internal
winding to make the external connections.
Load Factor
- A rating used by Fasco to show the
motors actual horsepower compared with nameplate rat-
ing. For example, if a 1/4 HP motor has a load factor of
1.3, it is actually 30% stronger than the 1/4 HP rating.
Lug
- Mounting bracket extending from the motor shell,
usually three or four.
Mechanical Duty
- Cooling by means of a fan inside or
outside the motor housing.
Microfarad (MFD)
- Capacitor rating
Motor
- A machine that converts electrical energy into
mechanical energy.
Mounting:
Rigid - Motor base welded solidly to the
motor shell.
Resilient - Motor mounted in a bracket or a
base using rubber rings on each end of the
motor to isolate vibration.
Stud - Motor uses its extended thru-bolts
(studs) to mount motor.
National Electric Code (NEC)
- A national code written
for the purpose of safeguarding persons and property
from the hazards arising from the improper use of elec-
tricity. Sponsored by the National Fire Protection
Institute. Used by insurance inspectors and by many gov-
ernment bodies regulating building codes. 51
NEMA
- The National Electric Manufacturers
Association. Construction and performance standards for
motors, controls, and most electrical machines in the U.S.
originate from this organization.
OEM
- Abbreviation for Original Equipment
Manufacturer.
O.D. (Outside Diameter)
- The abbreviation for Outside
Diameter. The dimension of a round object measured
across the outer edges at locations 180 degrees apart.
Ohms Law
- The basic relationship between the voltage,
current, and resistance in a circuit. Voltage = Current x
Resistance.
Overload Protector
- A temperature detecting device
built into the motor that disconnects the motor from the
power source if the temperature rise becomes excessive.
Permawick
- The oil-soaked cellulose fiber material that
is packed into the motor end plates for sleeve-bearing
lubrication. These fibers are made of 80 - 90% ground
wood fibers and 10 - 20% sulfite fibers.
Pitch
- Referring to the angle of the wings on a fan blade.
PSC
- Permanent-Split Capacitor
Resilient Mounting Ring
- This is a rubber ring that is
part of the end plate assembly on some motors. Its pri-
mary function is to provide the customer a means of
mounting the motor to a base or bracket on the equip-
ment. This ring isolates vibration.
Resistance
- This is the measure of a conductors ability
to conduct current. Resistance is measured in ohms. One
ohm of resistance will allow one amp to flow through a
conductor that has a voltage of one volt impressed on it.
Rotor
- The rotating member of a motor. It is construct-
ed from stacked iron laminations. There are channels in
the stack that are filled with molten aluminum. These
aluminum bars get currents induced in them from the
winding magnetic flux. The currents produce their own
magnetic flux. This rotor flux interacts with the winding
flux to produce rotation. The shaft is securely pressed on
the rotor.
RPM
- Shaft revolutions per minute. 52
GLOSSARY
Service Factor
- Pertains to self-cooled motors. A mea-
surement which states the percent horsepower the motor
can carry beyond its nameplate rating and remain self-
cooled. A service factor of 1.3 has a 30% horsepower
margin built into the motor.
Short
- This is a condition in the motor windings or con-
ductors where the absence of insulation causes currents to
by-pass their normal circuit path.
Sleeve-Bearing
- A sleeve style bushing used to support a
rotor in a motor. This style provides quiet motor operation
as compared to ball bearings.
Slip
- A term describing the difference between the rotor
speed and the speed of the motors rotating magnetic field.
Rotors always drag behind the speed of a magnetic field.
Slot Insulation
- Also called Slot Liner. The insulation
material used in the stator slots to protect the motor wind-
ings from scraping the laminations. It also provides wind-
ing protection against grounding to the laminations.
Special Purpose Motor
- Designed for a specific applica-
tion. Developed when an OEM has refined the operating
characteristics or construction features of the motor. Does
not have standard operating characteristics or standard
mec