Mitsubishi Electric FR-E700 Instruction Manual page 434

Special operation
Limit regeneration avoidance operation frequency (Pr. 885)
You can limit the output frequency compensated for (increased) by the regeneration avoidance
function.
The frequency is limited to the output frequency (frequency prior to regeneration avoidance op-
eration) + Pr. 885 "Regeneration avoidance compensation frequency limit value" during accel-
eration or constant speed. If the regeneration avoidance frequency exceeds the limit value dur-
ing deceleration, the limit value is held until the output frequency falls to 1/2 of Pr. 885.
When the regeneration avoidance frequency has reached Pr. 1 "Maximum frequency", it is lim-
ited to the maximum frequency.
When Pr. 885 is set to "9999", the frequency setting is invalid.
Regeneration avoidance function adjustment (Pr. 665, Pr. 886)
If the frequency becomes instable during regeneration avoidance operation, decrease the set-
ting of Pr. 886 "Regeneration avoidance voltage gain". Reversely, if sudden regeneration caus-
es an overvoltage alarm, increase the setting.
When vibration is not suppressed by decreasing the Pr. 886 setting, set a smaller value in
Pr. 665 "Regeneration avoidance frequency gain".
NOTES
When regeneration avoidance operation is performed, "oL" (over voltage stall) is displayed
and the OL signal is output.
When regeneration avoidance operation is performed, stall prevention is also activated at
the same time.
The regeneration avoidance function cannot shorten the actual deceleration time taken to
stop the motor. The actual deceleration time depends on the regeneration energy consump-
tion capability. When shortening the deceleration time, consider using the regeneration unit
(FR-BU2, FR-CV, FR-HC) and brake resistor (MRS, FR-ABR etc.) to consume regeneration
energy at constant speed.
When using the regeneration unit (FR-BU2, FR-CV, FR-HC) and brake resistor (FR-ABR
etc.), set Pr. 882 to "0 (initial value)" (regeneration avoidance function invalid). When using
the regeneration unit, etc. to consume regeneration energy at deceleration, set Pr. 882 to "2"
(regeneration avoidance function valid only at a constant speed).
When regeneration avoidance operation is performed, the OL signal output item of Pr. 156
also becomes the target of oL (over voltage stall). Pr. 157 "OL signal output timer" also
becomes the target of (over voltage stall).
6 - 294
Restriction level
Output frequency
Pr. 885
Pr. 885/2
Time
Fig. 6-150:
Limit the output frequency
Parameter
I001260E