Appendix C How to Select the Right AC Motor Drive
|
VFD-VL
C-2
C.1 Capacity Formulas
1. When one AC motor drive operates one motor
The starting capacity should be less than 1.5x rated capacity of AC motor drive
The starting capacity=
)
(
_
_
_
_
_
5
.
1
375
cos
973
2
kVA
drive
motor
AC
of
capacity
the
t
N
GD
T
N
k
A
L
×
≤
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
×
+
×
×
×
ϕ
η
2. When one AC motor drive operates more than one motor
2.1 The starting capacity should be less than the rated capacity of AC motor drive
Acceleration
time
≦
60 seconds
The starting capacity=
(
)
[
]
(
)
)
(
_
_
_
_
_
5
.
1
1
cos
1
1
1
kVA
drive
motor
AC
of
capacity
the
k
n
n
P
k
n
n
N
k
s
C
s
s
T
s
T
×
≤
+
=
+
×
×
⎥
⎥
⎥
⎦
⎤
⎢
⎢
⎢
⎣
⎡
−
−
ϕ
η
Acceleration
time
≧
60 seconds
The starting capacity=
(
)
[
]
(
)
)
(
_
_
_
_
_
1
cos
1
1
1
kVA
drive
motor
AC
of
capacity
the
k
n
n
P
k
n
n
N
k
s
C
s
s
T
s
T
≤
+
=
+
×
×
⎥
⎥
⎥
⎦
⎤
⎢
⎢
⎢
⎣
⎡
−
−
ϕ
η
2.2 The current should be less than the rated current of AC motor drive(A)
Acceleration
time
≦
60 seconds
)
(
_
_
_
_
_
_
5
.
1
1
1
A
drive
motor
AC
of
current
rated
the
k
n
n
I
n
S
M
T
S
T
×
≤
+
+
⎥
⎦
⎤
⎢
⎣
⎡
⎟
⎠
⎞
⎜
⎝
⎛
−
Acceleration
time
≧
60 seconds
)
(
_
_
_
_
_
_
1
1
A
drive
motor
AC
of
current
rated
the
k
n
n
I
n
S
M
T
S
T
≤
+
+
⎥
⎦
⎤
⎢
⎣
⎡
⎟
⎠
⎞
⎜
⎝
⎛
−
Call 1(800)985-6929 for Sales
deltaacdrives.com
Call 1(800)985-6929 for Sales
deltaacdrives.com
