Mitsubishi Electric FR-A800, Instruction Manual

Page: 866 / 1042

(G) Control parameters Parameters
5 - 686
What is regeneration avoidance operation? (Pr. 882, Pr. 883)
●
When the regenerative status is large, DC bus voltage will rise, which may cause overvoltage alarm
(E.OV[]).
Regenerative status can be avoided by detecting this rise of bus voltage, and raising the frequency
when the bus voltage level exceeds Pr. 883 "Regeneration avoidance operation level".
●
The regeneration avoidance operation can be selected to operate constantly or operate only
during constant speed.
●
The regeneration avoidance function is enabled by setting to Pr. 882 "Regeneration avoidance
operation selection" = "1, 2".
I001257E
Fig. 5-344: Regeneration avoidance function
NOTES The slope of frequency rising or lowering by the regeneration avoidance operation will change
depending on the regenerative status.
The DC bus voltage of the inverter will be approximately times of the normal input voltage.
The bus voltage will be approximately 311 V (622 V) DC in case of input voltage of 220 V (440 V)
AC.
However, it may vary depending on the input power supply waveform.
Make sure that the setting value of Pr. 883 will not get under DC bus voltage level. The frequency
will rise with operation of the regeneration avoidance function even at the time of no regenera-
tive status.
The stall prevention (overvoltage) (oL) will only operate during deceleration, stopping the lower-
ing of output frequency, but on the other hand, the regeneration avoidance function will con-
stantly operate (Pr. 882 = "1") or operate only at constant speed (Pr. 882 = "2"), and raise the
frequency depending on the amount of regeneration.
When the motor becomes unstable due to operation of the stall prevention (overcurrent) (OL)
during the regeneration avoidance operation, increase the deceleration time or lower the setting
of Pr. 883.
Under position control, the regeneration avoidance function is not activated.
Bus
v
o
lta
g
e
[V
D
C
]
Output
fr
eq
uenc
y [H
z]
Regeneration avoidance operation
example for acceleration
Regeneration avoidance operation
example for constant speed
Regeneration avoidance operation
example for deceleration
Pr. 883
Pr. 883
Pr. 883
During regeneration
avoidance function operation
During regeneration avoidance
function operation
Time
Time
Time
Bus
v
o
lta
g
e
[V
D
C
]
Output
fr
eq
uenc
y [
H
z]
Bus
v
o
lta
g
e
[V
D
C
]
Output
fr
eq
uenc
y [H
z]
During regeneration
avoidance function operation
Time
Time
Time
2