Mitsubishi Electric FR-A520-0.4K-NA Instruction Manual page 170

<Operation example>
Terminal
STF (STR)
·
When operation is performed with X19 (load detection high-speed frequency function selection) signal on,
the inverter automatically varies the maximum frequency between Pr. 4 "multi-speed setting (high speed)"
and Pr. 5 "multi-speed setting (middle speed)" settings as shown below according to the average current
flowing during acceleration from the frequency half of the Pr. 5 setting to the frequency set in Pr. 5.
Example: 1. If the average current is not more than half of the rated inverter current, the maximum
frequency is the value set in Pr. 4 as shown in operation example A.
2. If the average current is not less than the rated inverter current, the maximum frequency is the
value set in Pr. 5 as shown in operation example B.
<In this example, the frequency varies according to the current; 60Hz for 100% current
and 120Hz for 50% current.>
<Setting>
1) Set "2 or 3" in Pr. 270.
2) Assign X19 (load detection high-speed frequency function selection) to the input terminal using any of
Pr. 180 to Pr. 186.
3) Refer to the following table and set the parameters:
Parameter
Number
4 Multi-speed setting (high speed)
5 Multi-speed setting (middle speed)
271 High-speed setting maximum current
272 Mid-speed setting minimum current
273 Current averaging range
274 Current averaging filter constant
Pr.4
Pr.5
A
1
×
Pr.5
2
Less than 1/2 rated
current and driven load
CS
Pr.4
(120Hz)
Pr.5
(60Hz)
Pr.271
(50%)
Name Setting
0 to 400Hz
0 to 400Hz
0 to 200%
0 to 200%
0 to 400Hz
9999
1 to 4000
B
Pr.5
1
×
Pr.5
2
Not less than rated current
or regenerative load
Pr.272 Average current
(100%)
Set the higher-speed frequency.
Set the lower-speed frequency.
Set the upper and lower limits of the current at high and middle
speeds.
(Average current during acceleration from (Pr. 273 × 1/2) Hz to
(Pr. 273) Hz can be achieved.
Average current during acceleration from (Pr. 5 × 1/2) Hz to
(Pr. 5) Hz is achieved.
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 factory
setting is 12ms.) A larger setting provides higher stability but
poorer response.
158
PARAMETERS
ON
OFF
Description