# Operation Example - Mitsubishi Electric FR-A520-0.4K -55K Instruction Manual

Transistorized inverter, high function & low acoustic noise.

<Operation example>
1
×
Pr.5
2
Terminal
STF (STR)
CS
·
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
Name
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
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Pr.4
Pr.5
A
Pr.5
1
×
Pr.5
2
Less than 1/2 rated
Not less than rated current
Pr.4
(120Hz)
Pr.5
(60Hz)
Pr.272
Pr.271
(100%)
(50%)
Setting
0 to 400Hz
Set the higher-speed frequency.
0 to 400Hz
Set the lower-speed frequency.
0 to 200%
Set the upper and lower limits of the current at high and middle
speeds.
0 to 200%
(Average current during acceleration from (Pr. 273 × 1/2) Hz to
0 to 400Hz
(Pr. 273) Hz can be achieved.
Average current during acceleration from (Pr. 5 × 1/2) Hz to
9999
(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
1 to 4000
setting is 12ms.) A larger setting provides higher stability but
poorer response.
158
PARAMETERS
B
ON
OFF
Average current
Description