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159
T
ERMIN
O
L
OGY
GU
ID
E
T
ERM
S
&
CO
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O
N
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INDE
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M
O
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O
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C
TI
O
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GU
ID
E
Basic Considerations
It is important to select the motor that will help assure
optimum per
fo
rmance o
f
the appliance or equipment
to be driven. To do this, a motor must be selected that
is capable o
f
startin
g
the equipment, brin
g
in
g
it up to
operatin
g
speed, and drivin
g
it at the necessar
y
loadin
g
s
peed as lon
g
as required wit
h
out excessive heatin
g
.
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L
G
H
U
HG
in the
f
ollowin
g
order
:
A
pp
lication
.
G
eneral purpose, co
n
de
n
s
e
r
f
an, belted
f
an,
c
ompressor, hi
g
h pres
s
ure washer, etc.
M
otor T
y
pe
.
O
peratin
g
char
ac
t
e
ri
s
ti
cs
suc
h
as
:
c
apacitor start, capacitor start – ca
pac
i
tor run, split phase,
per
ma
n
ent split capacitor, shaded pole and three phase.
E
nclosure
.
The motor
’
s housin
g
t
y
pe, such as: open,
open drip-proo
f
, totall
y
e
n
c
losed
f
an cooled, totall
y
en
c
l
osed
n
o
n-v
en
t
i
lat
e
d, totall
y
enclosed air over, etc.
M
ountin
g.
C-face, resilient base, ri
g
id base, etc.
Bearin
g
s
.
S
leeve, ball
(
shields or seals
)
.
T
hermal Protection
.
T
y
pes o
f
protection include
automatic reset, manual reset, non-resettable, impedance
pro
t
ect
e
d and thermostat. Non-protected motors have
n
o internal thermal protector and should not be used
on applications that can start automaticall
y
or are out
of si
g
ht of the operator.
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ma
y
be made
f
or: horsepower, speed, volta
g
e, NEMA
f
rame size, service
f
actor and
f
ull load amps.
Service Factor
This is a measure o
f
the reserve mar
g
in built into a m
o
t
o
r.
It i
s
ex
p
ressed as a multiplier o
f
the rated hors
e
po
w
er
and determines permissible horsepower loadin
g
which
ma
y
be car
r
ied continuousl
y
under normal environmental
c
onditions. A motor o
p
er
at
ed
a
t
a
se
rvi
ce
f
ac
tor hi
g
her
than 1.0 will have a hi
g
her temperature rise and ma
y
have
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ra
t
ed
h
o
r
se
po
w
e
r. Locked rotor torque and breakdown
torque will remain u
n
c
han
g
ed.
E
xam
p
le
:
A motor operated at rated volta
g
e and
f
requenc
y
, nameplate ratin
g
1
/
4 HP, 1.35 service
f
actor.
1
/
4 HP x 1.35
S
F = .337 HP permissible loadin
g
i
f
the
ambient temperature does not e
x
c
eed 4
0°
C
.
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The insulation s
y
stem is made up o
f
the electrical
insulation materials used in the stator slot, wire
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HG
f
or temperature ratin
g
purposes based on its thermal
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temperatures
f
or lon
g
service li
f
e are
:
Class
A
105° C
Class B 130° C
Class F 155° C
Class
H
180° C
To determine the insulation class needed, add the
m
aximum ambient temperature and the maximum
temperature rise of the windin
g
of the m
o
t
o
r in th
e
application.
E
lectric Motor Terminolo
gy
Ambient
(
Amb
).
The temperature of the space around
th
e
m
o
t
o
r. M
os
t m
o
tors are desi
g
ned to operate in an
am
bi
e
nt not over 40
°C
(
104
°
F
)
.
Note
:
A ratin
g
o
f
40
°C
Ambient is not the same as
a ratin
g
o
f
40
°C
Rise, see
“
Temperature Rise.
”
Bearin
g
s
(
BRGS
).
Basic t
y
pes include
:
Self Ali
g
nin
g
Bearin
g
(
SAB
).
Pr
efe
rr
ed
wh
e
r
e
l
o
w
noise level is important, as on
f
an and blower motors.
U
nless otherwise stated, sel
f
ali
g
nin
g
bearin
g
motors
listed can be mounted in an
y
position, includin
g
sha
f
t-up
o
r
s
h
af
t-
do
wn.
Ball
.
Used where hi
g
her load capacit
y
, either axial
or radial, is r
e
q
uired or where the shaft speed is lower
than 500 RPM. Shields, metal rin
g
s with close runnin
g
c
learance on one side
(
sin
g
le-shielded
)
or both sides
(
do
u
b
l
e
-
s
hi
e
l
d
e
d
)
o
f
bearin
g
, and seals, which are similar
e
xcept with rubber lips that press a
g
ainst i
n
ner
race
,
m
o
r
e
ef
fec
tiv
e
l
y
e
x
c
l
ud
in
g
dirt, etc., are two barriers
used to keep out dirt.
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The ratio o
f
output power divided b
y
input
p
ower, usuall
y
e
x
p
ressed as a percenta
g
e. A measure
of how well the electrical ener
gy
input to a motor is
c
onverted into mechanical ener
gy
at the output shaft. The
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M
otor Terminolo
gy
Guid
e
TERMINOLOGY
GUIDE