Section 4
1MAC050144-MB C
Protection functions
318
615 series ANSI
Technical Manual
For instance, if the startup time of the motor is 11 seconds and the calculated operate time
of the thermal protection stage with no prior load is 25 seconds, one motor startup uses
11/25
≈
45 percent of the thermal capacity of the motor. Therefore, the restart disable level
must be set to below 100 percent - 45 percent = 55 percent, for example to 50 percent (100
percent - (45 p margin), where margin is 5 percent).
Setting the thermal alarm level
Tripping due to high overload is avoided by reducing the load of the motor on a prior
alarm.
The value of
Alarm thermal value
is set to a level which allows the use of the full thermal
capacity of the motor without causing a trip due to a long overload time. Generally, the
prior alarm level is set to a value of 80 to 90 percent of the trip level.
Summary of Contents for 615 Series ANSI
Page 1: ...Relion Protection and Control 615 series ANSI Technical Manual ...
Page 2: ......
Page 29: ...1MAC050144 MB C Section 615 series ANSI 22 Technical Manual ...
Page 389: ...Section 4 1MAC050144 MB C Protection functions 382 615 series ANSI Technical Manual ...
Page 485: ...Section 6 1MAC050144 MB C Supervision functions 478 615 series ANSI Technical Manual ...
Page 635: ...Section 10 1MAC050144 MB C Other functions 628 615 series ANSI Technical Manual ...
Page 711: ...Section 16 1MAC050144 MB C Glossary 704 615 series ANSI Technical Manual ...
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