BENSHAW RSi GM2 Series, Instruction Manual

Page: 139 / 282

Learning Advanced Features
890054-00-00
GM2 Series VFD 129
Speed Search Operation Setting Details
Code and
Features
Description
Cn.70 SS Mode
Select a speed search type.
Configuration Function
0 Flying Start-1
The speed search is carried out as it controls the inverter
output current below the Cn.72 (SS Sup-Current) setting.
Use when the direction of the idling motor and the
direction of the start command are the same. A stable
speed search function can be performed at about 10 Hz
or lower.
However, if the direction of the idling motor and the
direction of the start command are different, the speed
search does not produce a satisfactory results. The
direction of the idling motor cannot be established.
1 Flying Start-2
The speed search is carried out as it PI controls the ripple
current which is generated by the counter electromotive
force during no-load rotation. The counter electromotive
force is proportional to the idle speed. This mode
establishes the direction of the idling motor
(forward/reverse), and the speed search function is stable
regardless of the direction of the idling motor and
direction of the start command. However because the
ripple current is used, the frequency is not determined
accurately at low speeds (about 10
– 15 Hz). Re-
acceleration may start from zero speed.
Cn.71 Speed
Search
When the top LED segment is on, the corresponding bit is set to 1 (enabled). When
the bottom LED segment is on, the corresponding bit is 0 (disabled).
Speed search can be selected to operate among the following 4
conditions.
Type and Functions of Speed Search Setting
Configuration
Function
bit4 bit3 bit2 bit1
✓
Speed search for general
acceleration
✓
Initialization after a fault
✓
Restart after instantaneous power
interruption
✓
Starting with power-on
Items Bit On Status Bit Off Status
Keypad