1/4 HP 3 Phase Motor Protection

[3phmtr]

We are designing a 3-phase 1/4 HP motor for industrial fan application. Does anyone know

1. if NEC has a requirement for this motor to be protected for thermal or current overload by devices inside the motor?

2. if so, what kind of devices may work?

3. Klixon has a kind of 3-ph current/thermal protector can be mounted in side the motor, but this motor is too low in HP/amp fro using even their smallest protector. any other company's have similar protector?

4. can we use single-phase TP in each of the phases? and what will happen here in the case of thermal tripping?

Any advice or comments will be appreciated

 

[realolman]

can we use single-phase TP in each of the phases? and what will happen here in the case of thermal tripping?

It seems odd that you are able to design a 3 phase motor and not know the answer to that.

 

[SparkSparky101]

Am I missing something here but wouldn?t a simple overload block solve the prob?

 

[petersonra]

Am I missing something here but wouldn?t a simple overload block solve the prob?

for reasons that are not clear, he wants to put the thermal protection inside the motor, possibly so he can make the fan cord and plug connected.