Mitsubishi Electric FR-A700 Technical Manual page 303

[Pr. 49]
Stall Prevention Operation Level
A700 F700
Setting
RT signal-OFF
0(initial [Pr. 22] (Second stall prevention function is not
value)
0.01 to
Acceleration
400Hz
Constant
speed
Deceleration
[Pr. 22]
9999 *2
*1 The smaller setting of the stall prevention operation
levels set in [Pr. 22] and [Pr. 48] has a higher priority.
When [Pr. 48 = 0], stall prevention level operates as 0%.
*2 Even when stall prevention operation level is variable by
analog input, turning the RT signal ON also switches
from analog input level to the stall prevention operation
level using [Pr. 48]. (The second stall prevention
operation level cannot be input by analog.)
*3 When [Pr. 48 = 0], stall prevention operation is not
performed.
*4 When X9 signal is turned ON, the third stall prevention
function has precedence.
Stall Prevention Operation Level
A700
[Pr. 115]
X9
Setting
Signal-
OFF:
0(initial [Pr. 22] *1 (Third stall prevention function is not
value)
0.01 to
Accelera
[Pr. 22]
*1
400Hz
Constant
speed
Decelera
*1 As set in Second stall prevention operation.
*2 Stall operation level is as set in [Pr. 48] when the RT
signal is ON with [Pr. 49 = 9999]. When [Pr. 48 = 0], stall
prevention operation is not performed.
*3 The smaller setting of the stall prevention operation
levels set in [Pr. 22] and [Pr. 114] has a higher priority.
When [Pr. 114 = 0], stall prevention level operates as 0%.
RT signal-ON
activated)
Output [Pr. 49]
frequency < Output
≤ [Pr. 49]
frequency
[Pr. 22]
[Pr. 48] *1 [Pr. 22]
[Pr. 48] *3
X9 Signal-ON:
activated)
Output
[Pr. 115] <
frequency
Output
≤
frequency
[Pr. 115]
*2
[Pr. 22]
tion
*3 *3
[Pr. 114] [Pr. 22]
tion
(3) Stall prevention at double speed [Pr. 23,
Pr. 66]
common
During high-speed operation above the rated motor
frequency, acceleration may not be made because
the motor current does not increase. If operation is
performed in a high frequency range, the current at
motor lockup becomes smaller than the rated output
current of the inverter, and the protective function
(OL) is not executed even if the motor is at a stop.
To improve the operating characteristics of the motor
in this case, the stall prevention level can be reduced
in the high frequency range. This function is effective
for performing operation up to the high-speed range
on a centrifugal separator etc. Normally, set [Pr. 66 =
60Hz] and [Pr. 23 = 100%].
Setting [Pr. 23 Stall prevention operation level
compensation factor at double speed = 9999] (initial
value) will make the stall prevention operation level
constant up to 400Hz with [Pr. 22] setting.
Stall prevention
operation level at = A+B
Note that
Pr.22]
[Setting example] [Pr. 22 = 120%], [Pr. 23 = 100%], [Pr. 66 =
60Hz]
120
72
36
24
18
0 60
337
PARAMETER
[Pr. 22]-A [Pr. 23] -100
[Pr. 22]-B 100
[Pr. 66](Hz) [Pr. 22](%)
A =
Output frequency (Hz)
[Pr. 66](Hz) [Pr. 22](%)
B =
400 (Hz)
When [Pr.23 = 9999]
400Hz
Pr.66]
Output frequency (Hz)
100 200 300 400
Output frequency (Hz)
2