Sanken SVCO6, Инструкция по эксплуатации, Страница: 173 / 326

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7
7-3 Description of Functions
Protection function
The function blocks related to inverter protection function setting are described as follows.
F1701 Output current limiting function
The current at which the output current limiting function begins to work can be specified. This is useful for driving a
motor with a small capacity compared with that of the inverter, or to make the best use of the inverter capacity to achieve
the speediest acceleration.
Code No. Function Name Data Content Setting
Resolution
Factory Presets
F1701 Output current limiting
function
Mode A 0
：
Inactive
50-200%
1% 150
Mode B 0
：
Inactive
50-150%
120
●
The value is set with the ratio to rated current.
●
The so-called output current limiting function is used to limit the inverter‘s output current to prevent overload
during acceleration/deceleration or during normal operation. Use of this function enables the inverter to
temporarily operate in the ways described below:
1) During acceleration/deceleration: Reduce the acceleration/deceleration slope. This extends the time until the set
frequency is reached. The extended time varies depending on the magnitude of this setting and the inertia of the
load. Generally, accelerating or deceleration of a load with a large inertia requires a considerable current, requiring
a relatively high setting.
Example 1) When F1701=200% (Mode A).
Maximum use of the inverter capacity to minimize the acceleration/deceleration time.
(In mode B, the maximum value of F1701 is 150%)
Example 2) Set current limit to the same value as the rated current of a motor with small capacity:
F1701 = (rated motor current/rated inverter current) × 100[%].
However, the drive frequency can only be specified within a range of 50 - 200% of the rated current
of the inverter. (in mode A)
(Possible range of setting is 50-150% in mode B
）
2) During constant speed operation: When the inverter‘s output current exceeds this setting, the output frequency is
automatically reduced. The output frequency is reduced with the acceleration/deceleration slope specified by
F1703.
Note 1: The current limiting function during normal operation is generally useful for loads with a reduced torque such as
fans and pumps. However, this function has an adverse effect on overloads during constant speed operation with
loads with normal and constant torque. The factory preset, therefore, of F1703 (Output current limiting at constant
speed)= 0 disables the output current limiting function during operation. When driving reduced torque load, if the
F1703 ≠ 0, it is recommend to effectively use the output current limiting function during constant speed operation.
Note 2: During the acceleration/deceleration caused by the output current limiting function in constant speed operation, the
output current limiting function during acceleration/deceleration described in 1) and overvoltage stalling prevention
function do not work.
●
In vector control mode (speed control mode), because the torque limiter function is used to limit current, this
function may not work.
Reference parameter
F1003 (V/f pattern selection)
F1320 (Rating selection)
F1703 (Output current limiting at constant speed)