Answer Drives GT3000, Hardware & Software Manual

Page: 65 / 128

IMGT30017EN 53
5. APPLICATION NOTES
5A.1 General formulas describing a drive operation
M
U
L
I
L
L
I
D
, P
D
I
N
, A
N
U
N
P
M
η
inv
η
Μ
,
cos
ϕ
Μ
Rectifier
Inverter
Input
reactor
DC link
Capacitors
Figure 5A.2. One-line diagram of a drive with induction motor
N N N
I U A
⋅ ⋅ =
3
A
N
=
APPARENT DRIVE POWER
I
N
= D
RIVE RATED OUTPUT CURRENT
(RMS)
U
N
= D
RIVE RATED OUTPUT VOLTAGE
(RMS)
M M N M
A P
ϕ η
cos
⋅ ⋅ =
P
M
= M
ECHANICAL POWER AVAILABLE AT MOTOR SHAFT
η
M
= M
OTOR EFFICIENCY
COS
φ
M
= M
OTOR POWER FACTOR
inv M
M
D
P
P
η η
⋅
=
P
D
= P
OWER ON THE
DC
LINK
η
INV
= D
RIVE EFFICIENCY
L
D
D
U
P
I
⋅
=
35 . 1
I
D
= A
VERAGE CURRENT VALUE ON THE
DC
LINK
U
L
= I
NPUT VOLTAGE
(RMS)
D L
I I
⋅ =
87 . 0
I
NPUT
RMS
CURRENT
(
ASSUMING A
3%
INPUT REACTANCE
)
D L
I I
⋅ =
25 . 1
I
NPUT
RMS
CURRENT
(
WITHOUT INPUT REACTANCE
)
M M D
I I
ϕ
cos 32 . 1
⋅ ⋅ =
A
SSUMING
η
INV
= 0.97
M M L
I I
ϕ
cos 15 . 1
⋅ ⋅ =
I
NPUT
RMS
CURRENT
(
ASSUMING
3%
INPUT REACTANCE
& U
L
= U
N
)
M M L
I I
ϕ
cos 65 . 1
⋅ ⋅ =
I
NPUT
RMS
CURRENT
(
ASSUMING
0%
INPUT REACTANCE
& U
L
= U
N
)
Table A5.3 Useful Conversion Factors
Category Multiply By to Obtain
Length meters
meters
inches
feet
millimeters
3.281
39.37
0.0254
0.3048
0.0394
feet
inches
meters
meters
inches
Torque Newton-meter
lb-ft
lb-in
lb-ft
0.7376
1.3558
0.0833
12.00
lb/ft
Newton-meter
lb-ft
lb-in
Rotation RPM
RPM
degrees/s
rad/s
6.00
0.1047
0.1667
9.549
degrees/s
rad/s
RPM
RPM
Moment of Inertia Newton-meters
2
oz-in
2
lb-in
2
slug-ft
2
oz-in-sec
2
lb-in-sec
2
2.42
0.000434
0.00694
32.17
0.1675
2.68
lb-ft
2
lb-ft
2
lb-ft
2
lb-ft
2
lb-ft
2
lb-ft
2
Power watts
lb-ft/min
hp
hp
BTU/hour
0.00134
0.0000303
746.00
33000.00
0.293
hp
hp
watts
lb-ft/min
watts
Temperature degree C = (degree F-32) x 5/9)
degree F = (degree C x 9/5) + 32