Fire Pump Wiring (Part Winding)

Status
Not open for further replies.
E

ejones

New member
I have a Part Winding (Star / Delta) fire pump.
The building is under the 1999 code, and the part winding motor is not shown in the Fire Pump section. (Article 695-6)The manufacturer shows in the UL listing, to size conductors for the motor connection using 58% of the Motor FLA. My inspector demands the conductors be sized for 125% of the Motor FLA which makes the conductors a 4/0. Six 4/0 violates the wire bending space and wire fill within the peckerhead of the motor.
what is the solution?
 
Re: Fire Pump Wiring (Part Winding)

bigger peckerheads are avialible. check with any motor shop. also, i have in a pinch used large sheet metal j-boxes.
 
Re: Fire Pump Wiring (Part Winding)

ejones,

Article 110.3(B) Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

requirements like this should be followed.

frank
 
Re: Fire Pump Wiring (Part Winding)

Part-winding & star-delta (wye-delta) are actually two different methods. Or am I missing something?
 
Re: Fire Pump Wiring (Part Winding)

Part-winding & star-delta (wye-delta) are actually two different methods. Or am I missing something?
Click to expand...
They are different.

The part-winding starter energises half of the motor winding during starting, then energises the other half after a field-adjustable time delay. Six wires are required between the motor and starter, each carrying 50% of the nameplate FLA.
All (six) OL relay settings, and the size of the six wires between the starter and motor, are normally based on 125% of 50% of the FLA.

The wye-delta (star-delta) starter connects the motor phase windings in wye during starting, then changes the winding connection to a delta after a field-adjustable time delay. Six wires are required between the motor and starter, each carrying 58% of the nameplate FLA.
The (three) OL relay settings and wire size (six wires from starter to motor) are normally based on 125% of 58% of the FLA.

The sketch shows a typical wye-delta starter schematic showing the current division in one of the phases.

Ed

WyeDelta2.gif


[ June 02, 2005, 09:57 PM: Message edited by: Ed MacLaren ]
 
Status
Not open for further replies.
Top