Brochure

†
All marks shown within this document are properties o
f
their respective owners.
www
.
u
smotors.
com
16
1
T
ERMIN
O
L
OGY
GU
ID
E
T
ERM
S
&
CO
NDITI
O
N
S
INDE
X
M
O
T
O
R
S
ELE
C
TI
O
N
GU
ID
E
M
otor Terminolo
gy
Guid
e

D
irect Current
(
DC
).
Usable onl
y
i
f
D
C
power suppl
y
is available.
C
om
mon
ly
used on a
d
j
us
t
able-speed
applications.
M
ountin
g
(
MTG
)
 Ri
g
id
.
Motor solidl
y
f
astened to equi
p
ment throu
g
h metal
base
th
a
t i
s
bo
lt
ed
o
r w
e
l
d
e
d to motor shell, or moun
t
ed
t
o
H
QGVKLHOGKXEVZLWKRXWUHVLOLHQWULQ
J
V

VHH
³À
DQ
J
H´E
H
O
RZ


 Resilient
(
Res
)
.
S
ometimes called rubber or hub
mounted - motor shell isolated
f
rom base b
y
vibration
ab
so
r
b
in
g
material, such as rubber rin
g
s on the end
s
hields, to reduce transmission o
f
v
i
b
r
a
ti
o
n t
o
th
e
h
ousin
g
o
f
the unit or appliance.
 )DFHRUÀDQ
J
H


6
KD
I
WHQGHQGFRYHUKDVD
À
DWPRXQWLQ
J
s
ur
f
ace, machined to NEMA standard d
i
men
s
i
o
n
s
with
h
oles to allow eas
y
, secure moun
t
in
g
to the housin
g
o
f
the unit or appliance.
C
om
mon
l
y
used on
j
et pumps,
oil burners and
g
ear reducers.
 Stud
.
Motor has bolts extendin
g
f
rom
f
ront or rear, b
y
whi
c
h it i
s
m
ou
n
t
e
d.
Of
ten used on small, d
i
rec
t
d
riv
e
fa
n
s
a
n
d
b
l
o
w
e
r
s
.
 Yoke. Tabs or ears are welded to motor shell, to
allow boltin
g
to a
f
an column or brac
k
e
t.
U
sed on
fan-dut
y
motors.
P
ower
.
The ener
gy
used to do work. Also the rate at
which work is done. Measured in watts, hors
e
po
w
e
r, etc.
P
ower Factor
.
The ratio o
f
real power
(
watts
)
supplied
divided b
y
apparent power supplied
(
volt-amperes
)
. A
measure of how well power transmission or distr
i
bu
ti
o
n
sys
t
e
m
s
a
r
e
be
in
g
used. Do not confuse power factor with
H
I¿FLHQF
\

RPM
.
Rotational speed in revolutions per minute.
Rotation
(
Rot
).
Dir
ec
ti
o
n in whi
c
h
s
h
af
t r
o
t
a
t
es
:
C
W means clockwise;
CC
W means cou
n
t
e
r
c
l
ock
wise;
Re
v m
ea
n
s
r
e
v
e
r
s
i
b
l
e
. R
o
t
a
ti
o
n i
s
usu
a
ll
y
re
f
er
e
n
ced
f
rom the lead end
(
LE
)
o
f
the motor.
Service Factor
(
SF
).
A measure o
f
the reserve mar
g
in
bu
ilt int
o
a
m
o
t
o
r. M
o
tors rated
g
reater than 1.0
S
F have
more than normal mar
g
in, and are used where unusual
co
n
d
iti
o
n
s
suc
h
as
oc
ca
s
i
on
al hi
g
h or low volta
g
e,
mo
men
tar
y
overloads, etc. are likel
y
to occur. Used in
“
heav
y
dut
y
” applications.
T
em
p
erature Rise
.
The amount b
y
which a motor,
operatin
g
under rated conditions, is hotter than its
s
urroundin
g
s. The temperature rise ratin
g
on the motor
name
p
late has been replaced b
y
a listin
g
of maximum
am
bi
e
nt t
e
m
per
a
ture, insulation class and service factor.
S
ee “Insulation.
”
T
hermal Protector
.
A temperature or current sensin
g
device usuall
y
inte
g
ral within the motor, that disconnects
the motor windin
g
f
rom its power source to pr
e
v
e
nt
overheatin
g
due to overload or
f
ailure to start. Basic
t
y
pes o
f
thermal protectors include
:
Automatic Reset
(
Auto
).
After motor cools, pr
o
t
ec
t
o
r
automaticall
y
restores power.
S
hould not be used where
unexpected r
e
s
t
a
r
t
in
g
would be haz
a
r
d
ous
.

M
anual Reset
(
Man
).
An
e
xt
e
rn
a
l
bu
tt
o
n m
us
t
be
pushed to restore power to motor. Pre
f
erred where
unexpected restartin
g
would be ha
z
a
r
d
o
u
s
,
as
on
sa
w
s
,
con
v
eyors
,
com
pres
s
ors, etc.
Im
p
edance Protected
.
M
o
t
o
r i
s
de
s
i
g
ned with
V
X
I¿
FLHQWO
\
KL
J
KLQKHUHQWLPSHGDQFHWRSUHYHQW
overheatin
g
u
n
der an
y
condition o
f
load, i
n
c
l
ud
in
g
locked rotor
(
stalled
).
Non-resettable
(
one shot
).
When motor heats up the
protector contacts open, but cannot be reclosed. This
t
y
pe o
f
protector is used primaril
y
in u
n
at
t
e
n
d
ed
fa
n
s
where a stalled condition is usuall
y
not d
e
t
ect
ed
.
T
hermostat
.
Emplo
y
s a built-in tem
per
a
ture sensin
g
device, with external leads, which must be properl
y
co
nn
ec
t
ed
t
o
th
e
co
ntr
o
l
c
ir
cu
it
of
th
e
m
o
t
o
r
con
tr
o
ll
e
r
t
o
limit th
e
f
r
a
m
e
o
r win
d
in
g
temperature as required b
y
U
.L., the N.E.
C
.,
C
.
S
.A. or the
C
.E.
C
.
T
or
q
ue
.
Twist, or turnin
g
abilit
y
, supplied b
y
the shaft.
M
easured in
f
oot-pounds
(f
t-lbs
)
, inch-pounds
(
in-lbs
)
,
ounce-feet
(
oz-ft
)
or ounce-inches
(
oz-in
)
. Three torque
values are important.

L
ocked rotor or startin
g
torque. The torque pr
o
duced
a
t initi
a
l
s
t
a
rt
.
Breakdown tor
q
ue
.
The maximum torque a ru
n
n
in
g
motor will produce, without stallin
g
.

P
ull-u
p
tor
q
ue. The minimum torque available durin
g
th
e
ac
ce
l
er
a
tion period.
V
olta
g
e
.
Force pushin
g
electric current throu
g
h a cir
c
uit,
l
ike pres
s
ure in a water s
y
stem
.
TERMINOLOGY
GUIDE