MCP instantaneous setting

[Space]

Hello all, we have several Allen Bradley MCC's that control many of the plants motors. We have a 1.6A FLC motor that needs connected to an MCC bucket, the bucket has an Allen Bradley 15A MCP (Motor Circuit Protector ie. Instantaneous Trip Circuit Breaker) with instantaneous settings between 45-150A. I initially thought this MCP was too large because of it lowest instantaneous trip setting (45A) being greater than the normally allowed value of 800% FLC for the short circuit/ground fault protective device (430.52(C)(3)(b)(1).

However after reading 450.52(C)(3)(b)(3) it states if the FLC of the motor is 8 amps or less, an instantaneous trip circuit breaker (MCP) with continuous current rating of 15A or less shall be permitted to be increased to the value marked on the motor controller. I don't know exactly what that means, but it seems like they are saying you can use a 15A MCP and have the instantaneous setting at a value greater than the 800% max FLC for motors <8A FLC. I just don't fully comprehend what value marked on the motor controller means.

Looking for interpretations or firsthand experience if anyone has worked with MCC's / Motor Circuit Protectors. Thanks.

 

[Gilberth Bolanos]

¿Puedes subir una foto de la placa de identificación de ese motor? Confirmar que son motores de corriente continua de voltaje constante.

Translated
Can you upload a photo of the nameplate on that motor? Confirming that they are constant voltage DC motors.

 

[petersonra]

I think there is supposed to be an adhesive label that comes with the motor controller that is supposed to be put on the controller at the factory that has this information. However, I have not used an MCP this small before so I don't know for sure.

 

[Space]

¿Puedes subir una foto de la placa de identificación de ese motor? Confirmar que son motores de corriente continua de voltaje constante.

Translated
Can you upload a photo of the nameplate on that motor? Confirming that they are constant voltage DC motors.

I can't take a photo at my work, but here is the nameplate info. It is a 3 phase, 480V 3456RPM AC induction motor.

Watts: 500
V: 230/460
A: 2.10/1.05
Ph: 3
Hz: 60
RPM: 3456

I'm trying to determine if this motor is allowed to be protected by an 15A rated Motor Circuit Protector (Instantaneous Trip Breaker). The reason I have this question is because normally the instantaneous setting must not exceed 800% FLC per NEC Table 430.52, however there is an exception for motors less than 8A with a MCP rated 15A or less that may apply in this scenario.

I'm not at work right now, but I believe this is the MCP Model: Allen Bradley 140M-I8P-C15S-CXM

 

[Space]

I think there is supposed to be an adhesive label that comes with the motor controller that is supposed to be put on the controller at the factory that has this information. However, I have not used an MCP this small before so I don't know for sure.

Cool, thanks for the information. I'll try to look for this next work day.

 

[Gilberth Bolanos]

No puedo tomar una foto en mi trabajo, pero aquí está la información de la placa de identificación. Es un motor de inducción de CA trifásico de 480 V y 3456 RPM.

Vatios: 500
V: 230/460
A: 2,10/1,05
Tel: 3
Hz: 60
RPM: 3456

Estoy tratando de determinar si este motor puede protegerse con un protector de circuito de motor (disyuntor de disparo instantáneo) con clasificación de 15 A. La razón por la que tengo esta pregunta es porque normalmente el ajuste instantáneo no debe superar el 800 % de FLC según la Tabla 430.52 del NEC; sin embargo, existe una excepción para motores de menos de 8 A con un MCP con clasificación de 15 A o menos que puede aplicarse en este escenario.

No estoy trabajando ahora, pero creo que este es el modelo MCP: Allen Bradley 140M-I8P-C15S-CXM

Entiendo. Saludos.

 

[Gilberth Bolanos]

La clasificación o configuración seleccionada del cortocircuito del circuito derivado
y el dispositivo de protección contra fallas a tierra debe ser lo más bajo posible.
máxima protección. Sin embargo, si la clasificación o configuración especificada en
La Tabla 430.52 o lo permitido por 430.52(C)(1), Excepción No. 1, no es suficiente
Para la corriente de arranque del motor, se requiere una clasificación o ajuste más alto.
permitido por 430.52(C)(1), Excepción No. 2. Por ejemplo, una calificación más alta
Se permitiría que un motor se sometiera a condiciones de arranque severas en las que
El motor y la maquinaria que lo impulsa requieren un período de tiempo prolongado.
para alcanzar la velocidad deseada.