Fire pump wiring

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tyha

Senior Member
Location
central nc
I have a fire pump wired from controller. controller has utility and gen back up power. plans call to run 1 conduit 3p 480V from utility and gen power contactors in controller plus ground. 7 supply wires total. peker head has 12 leads. 4-7 5-8 6-9. 1,2,3 to phase as a usual 480v motor. my question is do leads 10, 11,12 go to the conductors coming from the genset contatctor in the controller because those are the numbers marked on the contactor terminals but the nameplate on motor states differently
 
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infinity

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Location
New Jersey
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Journeyman Electrician
Some fire pumps are configured WYE start/Delta run, others across the line. What type of fire pump controller are you using? Do you have a photo of the nameplate?
 

tyha

Senior Member
Location
central nc
I dont. however I want to say its wye start delta run. the thing is that there is no genset on site. we pulled to a gen box. so there wont be power there until after the fact.
 

tyha

Senior Member
Location
central nc
the name plate on the motor has leads 10, 11, 12 tied to 1,2,3 (not in that order) where the feed lands. so do both the gen set and utility power tie together on the 1,2,3 leads along with 10,11,12.
 

infinity

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Location
New Jersey
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Journeyman Electrician
A Wye start/Delta run will have 6 conductors from the starter to the fire pump motor. For a 12 lead motor you would end up with 6 pairs of motor leads which connect one pair to each of the 6 conductors form the starter.
 

tyha

Senior Member
Location
central nc
the motor has 4-7, 5-8,6-9, 2-12, 3-10, 1-11. there is no generator power. i understand 6 pairs but which feeders land where.the motor nameplate just shows a single L1 L2 L3 feed to leads 1,2,3 for the voltage 480V. the contactors in the controller have 1,2,3 for utility feed on the terminals and 10, 11, 12 on the generator contactor terminals. the numbers on the generator contactor terminals correspond to the proper phase the motor leads would tie to the 1,2,3 leads. so I wouldnt tie utility to 1,2,3 and gen set to 10, 11, 12 the 4-7, 5-8, 6-9.
 
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infinity

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New Jersey
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Does the FP controller have two inputs (normal and emergency) and one output (Wye start/Delta run)? The wiring to the motor shouldn't change if the power source switches from normal to EM.
 

tyha

Senior Member
Location
central nc
the controller has to inputs. utility and gen set. and cb's for each. from there through 2 contactors 1 utility and 1 gen power 3p we send 3 phase wires each and 1 ground in one conduit. 7 wires total. so 2 out puts
 

tyha

Senior Member
Location
central nc
normally with any 3p 480v motor. its tie leads 4-7, 5-8, 6-9 leads 1,2,3 to your feeder. the motor has the same diagram but shows leads 1,2,3 tied to the 10,11,12 leads. then has L1 L2 L3 at bottom as to tie to leads 1,2,3 but doesnt show where the gen set feeders go but the contactor terminals their connected to inside the controller for gen set are numbered 10,11,12
 

tyha

Senior Member
Location
central nc
come to think of it i think the controller may be an ATS as well. the line sides of the contactors are jumpered together phase a phase a, phase b phase b, phase c phase c. do they possibly connect inside the motor pecker head as well along with leads 10,11,12???? Im lost and theres a fire test monday.
 

Johnnybob

Senior Member
Location
Colville, WA
So a twelve lead motor hooks up just like the name plate says. 4-7, 5-8, 6-9 then t1 to 1&12, t2-2&10, t3-3&11. I would guess your t leads from both starters will hook up together, so either starter will start motor if utility power drops out
 

tyha

Senior Member
Location
central nc
thats sort of what im thinking. although I noticed this morning that the numbers on the contactor for the gen power in the controller have not only numbers 10, 11, 12 but also 4,5, and 6 as if it were a wye/delta wired
 

Johnnybob

Senior Member
Location
Colville, WA
So having never wired a fire pump motor, not sure about the contactor. I would think if the controller did the wye/delta switching, there would be 2 contactors, or at least 2 sets of contacts so one set could drop out when the motor gets up to speed, still need a centrifugal switch to drop one out. I have however, wired several 12 lead motors, and I always thought that the extra three leads were so you could wire it either way. For a wye, 10, 11 and 12 would tie together to create the center of the wye/star configuration, or to your 1, 2 and 3 leads to complete your delta.
 

Johnnybob

Senior Member
Location
Colville, WA
Wye-delta-open-transition-3-phase-motors.jpg
??????
 

tyha

Senior Member
Location
central nc
The contactors are in the fire pump controller. the fire pump nameplate shows 480V taps as 1-12, 2-10, 3-11, 4-7, 5-8, 6-9 and L1 L2 L3 to 1,2,3 along with there associated taps to 12, 10 and 11 respectively. Im almost sold that its a wye delta so I would connect normal utility as shown for L1,L2 and L3 and connect the 3 phase wires from gen set contactor inside controller to 4,5 and 6. its either this or the cables from controller are all connected to L1, L2 and L3. I just wish someone here actually wired a 12 lead fire pump from a controller and said yes thats what you do.
 

Johnnybob

Senior Member
Location
Colville, WA
First, it would be the T leads from contactor to motor. Second, I don't think you're gonna be using the genny and the utility power at the same time! Third, if you ever have to use a fire pump, it's pretty much an all or nothing situation, and your genny won't start, nor​ should your emergency control contactor pull in, unless you've lost utility power.
 

Johnnybob

Senior Member
Location
Colville, WA
First, it would be the T leads from contactor to motor. Second, I don't think you're gonna be using the genny and the utility power at the same time! Third, if you ever have to use a fire pump, it's pretty much an all or nothing situation, and your genny won't start, nor​ should your emergency control contactor pull in, unless you've lost utility power.
I guess the thing that confuses me, is why would it start from a wye config. under normal power, then start from a delta under emergency back-up power?
 

tyha

Senior Member
Location
central nc
I actually took a shot in the dark and made it up correctly. 12 lead motor nameplate states T1-T12, T2-T10, T3-T11
T4-T7, T5-T8, T6-T9. Also T1,T2,T3 to LI, L2, L3. so the 6 wires (3 normal utility) (3 EM Gen Power) from controller contactors I connected T1, T2, T3 to normal L1, L2,L3 4-7, 5-8, 6-9, 10-L2 em, 11-L3 em, 12-L1 em. I couldnt find this on any diagram. they kept saying the em leads connect to 4-7, 5-8, 6-9. when I drew the Y and delta out it didnt make sense to do tjis as there was no gen power available. Im assuming once em power is supplied utility is obviously down and it runs from the 10,11,12 leads.... correct???
 

don_resqcapt19

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Staff member
Location
Illinois
Occupation
retired electrician
I actually took a shot in the dark and made it up correctly. 12 lead motor nameplate states T1-T12, T2-T10, T3-T11
T4-T7, T5-T8, T6-T9. Also T1,T2,T3 to LI, L2, L3. so the 6 wires (3 normal utility) (3 EM Gen Power) from controller contactors I connected T1, T2, T3 to normal L1, L2,L3 4-7, 5-8, 6-9, 10-L2 em, 11-L3 em, 12-L1 em. I couldnt find this on any diagram. they kept saying the em leads connect to 4-7, 5-8, 6-9. when I drew the Y and delta out it didnt make sense to do tjis as there was no gen power available. Im assuming once em power is supplied utility is obviously down and it runs from the 10,11,12 leads.... correct???
No. There is no way that both sources connect directly to the motor.
 
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