Motor

[Hameedulla-Ekhlas]

Greeting all,
We usually design motor breaker 2.5 the largest and plus the others. When motor's starting current will be 6-8 times. Is this true or it has a specific usage and condition.

 

[mcclary's electrical]

Greeting all,
We usually design motor breaker 2.5 the largest and plus the others. When motor's starting current will be 6-8 times. Is this true or it has a specific usage and condition.

The 6-8 times is a rule of thumb,,,,and is close for lots of motors. Although,,,to say the rule is true for all motors would be impossible

 

[Cold Fusion]

Greeting all,
We usually design motor breaker 2.5 the largest and plus the others. When motor's starting current will be 6-8 times. Is this true or it has a specific usage and condition.

In addition to mcc's reply (which is absolutely true), Nema MG-1 has a lot on information on this. Also, look at NEC T430.7.B. That gives the coorelation betwen LRC and the nameplate code letter. Note this is different from the design letter.

One thing that has always puzzled me is the NEC refering to the Design letter to size the Short circuit protection. I have never understood why they don't refer to the Code letter.

cf

 

[Hameedulla-Ekhlas]

thank you all,