Specifications
Table Of Contents
- Preface
- Table of Contents
- Chapter 1 Introduction
- Chapter 2 Installation and Wiring
- Chapter 3 Start Up
- Chapter 4 Digital Keypad Operation
- Chapter 5 Parameters
- 5.1 Summary of Parameter Settings
- Group 0 User Parameters
- Group 1 Basic Parameters
- Group 2 Operation Method Parameters
- Group 3 Output Function Parameters
- Group 4 Input Function Parameters
- Group 5 Multi-Step Speed and PLC Parameters
- Group 6 Protection Parameters
- Group 7 Motor Parameters
- Group 8 Special Parameters
- Group 9 Communication Parameters
- Group A PID Parameters
- 5.2 Parameter Settings for Applications
- 5.3 Description of Parameter Settings
- Group 0: User Parameters
- Group 1: Basic Parameters
- Group 2: Operation Method Parameters
- Group 3: Output Function Parameters
- Group 4: Input Function Parameters
- Group 5: Multi-step Speeds and PLC (Process Logic Control) Parameters
- Group 6: Protection Parameters
- Group 7: Motor Parameters
- Group 8: Special Parameters
- Group 9: Communication Parameters
- Group A: PID Control
- 5.1 Summary of Parameter Settings
- Chapter 6 Fault Code Information
- Chapter 7 Troubleshooting
- 7.1 Over Current (OC)
- 7.2 Ground Fault
- 7.3 Over Voltage (OV)
- 7.4 Low Voltage (Lv)
- 7.5 Over Heat (OH)
- 7.6 Overload
- 7.7 Keypad Display is Abnormal
- 7.8 Phase Loss (PHL)
- 7.9 Motor cannot Run
- 7.10 Motor Speed cannot be Changed
- 7.11 Motor Stalls during Acceleration
- 7.12 The Motor does not Run as Expected
- 7.13 Electromagnetic/Induction Noise
- 7.14 Environmental Condition
- 7.15 Affecting Other Machines
- Chapter 8 Maintenance and Inspections
- Appendix A Specifications
- Appendix B Accessories
- Appendix C How to Select the Right AC Motor Drive

Chapter 8Appendix C How to Select the Right AC Motor Drive
|VFD-S Series
Revision August 2008, SE09, SW V2.61 C-3
2.3 When it is running continuously
The
requirement
of load capacity should be less than the capacity of the AC
motor drive(kVA)
The requirement of load capacity is
)(_____
cos
kVAdrivemotorACofcapacitythe
Pk
M
≤
×
×
ϕη
The motor capacity should be less than the capacity of AC motor drive
)(_____103
3
kVAdrivemotorACofcapacitytheIVk MM ≤××××
−
The current should be less than the rated current of AC motor drive(A)
)(______ AdrivemotorACofcurrentratedtheIk M ≤×
Symbol explanation
M
P
: Motor shaft output for load (kW)
η
: Motor efficiency (normally, approx. 0.85)
ϕ
cos
: Motor power factor (normally, approx. 0.75)
MV
: Motor rated voltage (V)
M
I
: Motor rated current (A), for commercial power
k
: Correction factor calculated from current distortion factor (1.05-1.1, depending on
PWM method)
1CP
: Continuous motor capacity (kVA)
Sk
: Starting current/rated current of motor
Tn
: Number of motors in parallel
Sn
: Number of simultaneously started motors
2
GD
: Total inertia (GD
2
) calculated back to motor shaft (kg m
2
)
L
T
: Load torque
A
t
: Motor acceleration time
N
: Motor speed










