ANSI Code Impedances
|
|
Momentary Duty |
Interrupting Duty |
---|---|---|---|
Synch |
Synchronous |
1.0 X"dv |
1.5 X"dv |
Ind>1000 |
Induction Motor > 1000 Hp |
1.0 X"dv |
1.5 X"dv |
> 250 @ 3600 |
Induction Motor > 250 Hp at 3600 RPM |
1.0 X"dv |
1.5 X"dv |
>50 |
Induction Motor or Motor Group > 50 Hp |
1.2 X"dv |
3.0 X"dv |
<50 |
Induction Motor Group < 50 Hp |
1.67 X"dv |
Infinite X"dv |
Lumped |
Lumped Induction Motor Group |
1.0 X"dv (X=25%) |
3.0 X"dv |
Note: X" for induction motor groups >50 HP and <50 HP are typically assumed equal to 16.7%. Using the impedance multipliers, this corresponds to an equivalent motor contribution of 3.6 to 4.8 times the full load current.