Motor calculation

[electricrw]

When trying to size a inverse time breaker on a motor and given that the motor is a 5min intermittent duty motor.
Would you consider that motor a wound roter or a squirrel cage type?
I am trying to find out if I can use 250% or 150% for my over current device calculation on table 430.52 form 05 code book. Thanks again for everybody that is helping me with this question.

 

[jdsmith]

When trying to size a inverse time breaker on a motor and given that the motor is a 5min intermittent duty motor.
Would you consider that motor a wound roter or a squirrel cage type?
I am trying to find out if I can use 250% or 150% for my over current device calculation on table 430.52 form 05 code book. Thanks again for everybody that is helping me with this question.

Intermittent duty and the type of rotor construction are two different issues. A wound rotor vs. squirrel cage is a physical characteristic of how the rotor is constructed. Most motors are the squirrel cage type. It sounds like you already have a motor that you need to hook up? I can't comment more because I don't have my NEC in front of me (and before someone posts the link to the online one, I have it but I don't like computerized reference materials.:smile

 

[frenchelectrican]

most squrell cage motor you can go up to 250% of the FLA but however with wound rotors they are only can go 150% of FLA for choosing the proper OCPD on it.

but with interment duty motors they have diffrent set of FLA figures which i don't have the chart with me right now but they have insterning formaila on them.

Merci,Marc