Motor controls

[JdoubleU]

I posted a thread not long ago about a 3 phase condensate pump that was using the float as the only source of control. I did double check the float switch and they ran phase A and C through the contacts and just ran phase B straight through to the motor. Is this up to Code. I would think not. I would think it would need a starter so as to cut off all phase conductor in case of an overload.

 

[augie47]

A starter (manual or magntic) could provide the overload protection, however, it could also be provided by a thermal device in the motor or by fuses in the supply circuit.

 

[RUWired]

I posted a thread not long ago about a 3 phase condensate pump that was using the float as the only source of control. I did double check the float switch and they ran phase A and C through the contacts and just ran phase B straight through to the motor. Is this up to Code. I would think not. I would think it would need a starter so as to cut off all phase conductor in case of an overload.

Article 430.84 only needs to switch enough conductors to control the motor. Two of the three would be enough.

430.84 Need Not Open All Conductors.
The controller shall not be required to open all conductors to the motor.
Exception: Where the controller serves also as a disconnecting means, it shall open all ungrounded conductors to the motor as provided in 430.111.

 

[JdoubleU]

Thank you very much for your reply. Now in this case if the motor did not have overload protection inside it it would by code need it and therefor need a starter.

 

[augie47]

Although, IMO, it should, by Code I don't know that it is required. 430.36 provides guidance for using fuses as overload protection, so, a set of properly sized fuses is allowed.