Mitsubishi Electric FR-A700 Series, Техническое руководство

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395
PARAMETER
2
P
ARAM
ETE
R
2.20 Other function
2.20.1 Load torque high speed frequency control [Pr. 4, 5, 270 to 274]
(A700)
Load torque high speed frequency control is a function
which automatically sets the operational maximum
frequency according to the load.
More specifically, the magnitude of the load is judged
according to the average current at a certain time after starting to perform operation at higher than the preset
frequency under light load.
This function is designed to increase speed automatically
under light load, for example to minimize the incoming/
outgoing time in a multi-story parking lot.
Set [ Pr. 270 Stop-on contact/load torque high-speed frequency
control selection = 2 or 3
].
When operating with the load torque high speed frequency
function selection signal (X19) ON, the inverter
automatically changes the maximum frequency within the
setting range of [
Pr. 4 Multi-speed setting (high speed)
] and
[ Pr. 5 Multi-speed setting (middle speed) ] according to the
magnitude of the average current during the time to
accelerate from 1/2 of the frequency set in [
Pr. 5 ] to the
frequency set in [
Pr. 5
].
When the average current of the current averaging range
(refer to A in the chart on the next page) during operation
with the X19 signal on is less than the "rated inverter
current"
×
[
Pr. 271
], the maximum frequency automatically
becomes the [ Pr. 4 ] setting value.
When the average current of the current averaging time
period (refer to B in the chart on the next page) during
operation with the X19 signal on is higher than the "rated
inverter current"
×
[ Pr. 272 ], the maximum frequency
automatically becomes the [ Pr. 5 ] setting value.
During regeneration load operation, [ Pr. 5 ] is the maximum
frequency regardless of the average current. When the
average current during acceleration is too small, it may be
judged as regeneration and the maximum frequency
becomes the setting of [
Pr. 5 ].
The current averaging range can be set between 1/2
frequency of the [
Pr. 273 ] setting value and [ Pr. 273 ] set
frequency.
When the current averaging range includes the constant
power range, the output current may become large in the
constant power range.
When the average current value in the current averaging
range is small, deceleration time becomes longer as the
running frequency increases.
The maximum output frequency is 120Hz. The output
frequency is 120Hz even when the setting is above 120Hz.
Set [
Pr. 178 to Pr. 189 (input terminal function selection) = 19 ]
and assign X19 signal function to the input terminal.
This control can be activated at every start. Fully note that
the speed changes every time if the magnitude of the load
differs every time.
It is valid in the External operation mode only, and restart
after instantaneous power failure function and fast-
response current limit function are invalid.
The load torque high speed frequency function is invalid in
the following operation conditions.
• PU operation ([ Pr. 79 ])
• PU+external operation ([ Pr. 79 ])
• JOG operation (JOG signal)
• PID control operation (X14 signal)
• Remote function selection operation ([
Pr.59 ])
• Orientation control operation
• Multi-speed setting (RH, RM, and RL signals)
• 16bit digital input (FR-A7AX)
A700
[Pr.] Name
Initial
Value Setting
Range
Description
4 Multi-speed setting (high speed) 60Hz 0 to 400Hz Set the higher-speed frequency.
5 Multi-speed setting (middle speed) 30Hz 0 to 400Hz Set the lower-speed frequency.
270
Stop-on contact/load torque high-
speed frequency control selection
0
0 Normal operation
1 Stop-on-contact control (refer to page 396)
2 Load torque high speed frequency control
3
Stop-on-contact (refer to page 396) +load torque high speed frequency
control
271
High-speed setting maximum
current
50% 0 to 220%
Set the upper and lower limits of the current at high and middle speeds.
272 Middle-speed setting minimum
current
100% 0 to 220%
273 Current averaging range 9999
0 to 400Hz
Average current during acceleration from ([ Pr. 273 ] 1/2) Hz to ([ Pr. 273 ])
Hz can be achieved.
9999
Average current during acceleration from ([ Pr. 5 ] 1/2) Hz to ([ Pr. 5 ] ) Hz
is achieved.
274
Current averaging filter time
constant
16 1 to 4000
Set the time constant of the primary delay filter relative to the output
current. (The time constant [ms] is 0.75 [
Pr. 274
] and the initial value is
12ms.) A larger setting provides higher stability but poorer response.