BENSHAW RSi SG Series, Instruction Manual

Page: 120 / 218

Chapter 6 - Parameter Description [AFN]
6-32
AFN-60: Control Mode Selection
Selects the control mode of the drive.
AFN-60 Setting Description
V/F V/F Control
Slip compensation Slip compensation
Sensorless
Sensorless vector control
speed operation
◈
V/F control:
This parameter provides a constant voltage/frequency
ratio. It is recommended for most general-purpose
applications. To increase the starting torque with this
method, increase the torque boost function.
Related function: AFN-67~69 [Torque boost]
◈
Slip compensation:
This function is used to maintain a constant motor
speed, even with varying loads. To keep the motor
speed constant, the actual output frequency will change
in response to varying loads. The amount of frequency
that the load varies is limited by the Rated Slip, (AFN-
42). For example, when the motor speed decreases
below the reference speed (frequency) due to a heavy
load, the drive increases the output frequency higher
than the reference frequency to increase the motor
speed. The drive increases or decreases the output by
the delta frequency shown below.
Motor parameters AFN-41~46 and DRV-05 are
automatically determined by AFN-40 [Motor
selection]. The default settings are typically acceptable;
however the parameters may be fine-tuned if necessary.
AFN-40~46, DRV-05 [Motor related parameters for
Slip Compensation]
Param
LCD
Display
Description
AFN-40 Motor select Select motor capacity
AFN-42 Rated-Slip Motor rated slip (Hz)
DRV-05 Rated-Curr
Motor rated current
(rms)
AFN-44 Noload-Curr
Motor no load current
(rms)
AFN-45 Efficiency Motor efficiency (%)
AFN-46 Inertia rate Motor inertia rate
Note: Incorrectly setting AFN-44 [Motor No-load
Current] may degrade the Sensorless Vector control
performance.
◈
Sensorless Vector speed control operation:
Use sensorless vector control when 1) high starting
torque is required at low speeds 2) the load fluctuates
3) fast torque response times are needed.
For proper operation set AFN-40~46, DRV-05 [Motor
parameters] and AFN-60 [Control mode select]
properly.
Set “Yes” in AFN-61 [Auto tuning] first before using
this control.
Related parameters: AFN-40~46, DRV-05, AFN-60,
AFN-62~66
Parameter
LCD display Parameter
AFN-62 RS Stator resistance
AFN-63 Lsigma Leakage inductance
AFN-65 SL P-gain Sensorless P gain
AFN-66 SL I-gain Sensorless I gain
Guide for Optimal Use of Sensorless Vector Control
For optimum use of sensorless vector control, the
following conditions should be met. If one of the
following conditions is not satisfied, the drive and
motor may not work properly due to insufficient
torque, cogging, or excessive motor noise. In any of the
following situations are not satisfied, it is
recommended to use V/F Control or Slip
Compensation control instead of sensorless vector
control.
▣ The motor capacity should be equal to or one
horsepower level lower than the drive capacity.
AFN ► Control mode
60 V/F
Factory Default:
V/F
Delta freq (Slip Comp. Freq.) = Motor Rated slip *
(Output current - Motor No load current) / (Motor rated
current - Motor No load current)
Output freq = Reference freq + Delta freq