130
5. Speed Control
5.8 Avoiding motor overrunning
5.8
Avoiding motor overrunning
Motor overrunning due to excessive load torque or an error in the setting of the number of encoder pulses can be avoided.
*1
This is the overspeed detection frequency under encoder feedback control. (Refer to
).
*2
The setting is available when a Vector control compatible option is installed.
Speed deviation excess detection (Pr.285, Pr.853)
• A shutoff can be set for when the deviation between the set frequency and the rotation speed (estimated value) is large,
such as when the load torque is excessive.
• When the difference (absolute value) between the speed command value and the rotation speed (estimated value) is equal
to or higher than the setting value in
Pr.285 Speed deviation excess detection frequency
for a continuous time equal
to or longer than the setting value in
Pr.853 Speed deviation time
, the speed deviation excess detection (E.OSD) is
activated to shut off the inverter output.
NOTE
• This function is enabled at a frequency equal to or higher than 10% of the rated motor frequency under PM sensorless vector
control.
Speed limit (Pr.873)
• This function prevents overrunning even when the setting value for and the value of the actual number of pulses are
different. When the setting value for the number of encoder pulses is lower than the actual number of pulses, because the
motor may increase speed, the output frequency is limited with the frequency of (set fre
Pr.873
).
Vector
Vector
Vector
PM
PM
PM
Pr.
Name
Initial value
Setting
range
Description
285
H416
Speed deviation excess detection
frequency
9999
0 to 30 Hz
Set the speed deviation excess detection frequency
(difference between the rotation speed (estimated value)
and the speed command value) at which the protective
function (E.OSD) activates.
9999
No speed deviation excess
853
H417
Speed deviation time
1.0 s
0 to 100 s
Set the time from when the speed deviation excess state
is entered to when the protective function (E.OSD)
activates.
873
H415
Speed limit
20 Hz
0 to 400 Hz
Set the frequency limit with the set fre
Pr.873
value.
690
H881
Deceleration check time
1.0 s
0 to 3600 s
Set the time required to shut off output due to
deceleration check.
9999
No deceleration check
Set frequency
Rotation speed (estimated value)
Time
Speed deviation
excessive fault activated
(E. OSD)
ON
OFF
Fault output
(ALM)
Pr.853
Pr.285
Frequency
(Hz)
Actual speed
at error occurrence
Set speed +
Pr. 873
value
Value of
Pr. 873
Set speed
Speed during
normal operation
Summary of Contents for FR-E800
Page 17: ...16 1 Introduction 1 3 Related manuals MEMO ...
Page 51: ...50 2 Basic Operation 2 8 I O terminal function assignment MEMO ...
Page 89: ...88 3 Parameters 3 4 Parameter list by function group number MEMO ...
Page 135: ...134 5 Speed Control 5 9 Troubleshooting in the speed control MEMO ...
Page 153: ...152 6 Torque Control 6 7 Troubleshooting in torque control MEMO ...
Page 195: ...194 8 E Environment Setting Parameters 8 18 Current average value monitor signal MEMO ...
Page 237: ...236 10 D Operation Command and Frequency Command 10 6 Operation by multi speed setting MEMO ...
Page 339: ...338 13 T Multi Function Input Terminal Parameters 13 9 Start signal operation selection MEMO ...
Page 455: ...454 16 G Control Parameters 16 13 Speed smoothing control MEMO ...
