Speed Smoothing Control - Mitsubishi Electric FR-A800 Series Instruction Manual

 Setting the break point for droop control (Pr.994, Pr.995)
• Set Pr.994 and Pr.995 to have a break point on a droop compensation frequency line. Setting a break point allows the
inverter to raise the droop compensation frequency for light-load (no load) operation without raising it for heavy-load
operation.
Droop compensation
reference
NOTE
• The droop break point function is disabled when any of the following conditions is met. (Linear compensation by Pr.286 is
performed.)
Pr.995 = 100% (initial value)
Pr.286 < Pr.994
Pr.994 ≤ Pr.995 × Pr.286 / 100%
 Setting multiple droop control types (Pr.679 to Pr.683)
• When the second droop control is set, two sets of droop controls can be switched for use. Turning ON the Second function
selection (RT) signal enables the second droop control.
NOTE
• The RT signal is the Second function selection signal which also enables other second functions.
• The RT signal is assigned to terminal RT in the initial status. Set "3" in one of Pr.178 to Pr.189 (Input terminal function
selection) to assign the RT signal to another terminal.
• Changing the terminal assignment using Pr.178 to Pr.189 (Input terminal function selection) may affect the other functions.
Set parameters after confirming the function of each terminal.
Parameters referred to
Pr.1 Maximum frequencypage 428
Pr.178 to Pr.189 Input terminal function selection

5.16.17 Speed smoothing control

V/F V/F V/F
The output current (torque) of the inverter sometimes becomes unstable due to vibration caused by mechanical resonance.
Such vibration can be suppressed by reducing fluctuation of the output current (torque) by changing the output frequency.
Pr.
653 Speed smoothing
G410 control
654 Speed smoothing
G411 cutoff frequency
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Increased amount of the
droop compensation
frequency
Droop compensation
frequency
-100%
page 521
Name Initial value
0%
20 Hz
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Frequency
Droop break point gain
(Pr.994)
Droop break point torque
(Pr.995)
0
100%
Setting
range
Check the effect by increasing and decreasing the value at around
0 to 200%
100%.
0 to 120 Hz Set the minimum frequency for the torque variation cycle.
Droop gain
(Pr.286)
Torque
Description
5. PARAMETERS
5.16 (G) Control parameters
1
2
3
4
5
6
7
8
9
10
741