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(2) Torque characteristics
2 Speed detection hysteresis (Pr.870)
Low-speed
range high-
torque
characteristic
Torque characteristic
Enabled
(Pr.788 =
“1”)
With one rank higher inverter
Disabled
(Pr.788 =
“0”)
This function prevents chattering of the speed detection signals.
Parameter
Number
Name
Initial
Value
Setting
Range
Description
870
Speed detection
hysteresis
0Hz* 0 to 5Hz Set the hysteresis width for the detected frequency.
* Performing IPM parameter initialization changes the settings. (Refer to page 6)
When an output frequency fluctuates, the following
signals may repeat ON/OFF (chatters).
Up to frequency (SU)
Speed detection (FB, FB2, FB3)
Low speed output (LS)
Setting hysteresis to the detected frequency prevents
chattering of these signals.
REMARKS
Setting a higher value to this parameter slows the response of frequency detection signals (SU, FB, FB2, FB3, and LS).
The ON/OFF logic for the LS signal is opposite for the FB signal.
2000100
150
200
100
Continuous
operation region
120
Instantaneous
(3s) operation region
Torque %
Speed r/min
3000
Short duration
(60s) operation region
2000100
150
200
100
Instantaneous
(3s) operation region
Continuous
operation region
Torque %
* Zero speed up to a 150% instantaneous output torque
Speed r/min
3000
Short duration
(60s) operation region
2000 3000200
150
200
100
Torque %
Speed r/min
Instantaneous
(3s) operation region
Continuous
operation region
50
Short duration
(60s) operation region
Pr.870
Pr.42
ON
ON
ON
FB
Example of the speed detection signal (FB)
Output
frequency (Hz)
OFF OFF
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