Pre-Warning: This is a long winded message!
Yoopersup's Project, as described, is not like any Fire Pump Design / Build I have ever dealt with!; i.e., the Primary Pump & Motor, along with the Pressure Maintenance Pump(s) - AKA "Jockey Pump(s)", are only in use during an Emergency Event.
Nevertheless, this Project does include an Emergency related item, designated for Fire Extinguishing usage, so the Design approach would be similar to any other Fire Pump with an Emergency Power source.
Can one transfer switch be used for both Fire pump controller & control power panel?
generator sizing ? (remember Fire Pump)
125 hp 3 phase. 480
10kva Transformer for misc. 480/120/240v 1phase
I would believe the related Equipment, connected through a single ATS, with a "Dedicated" Emergency Generator driving the Equipment during an outage, will be compliant.
Include the existing 30 HP Pump Motor in this Equipment list too.
I suggest to first propose the Design concepts stated in the opening post, to Building & Fire Departments for comments, then go from there. Include a Single Line Drawing for references.
This will give you an idea of what to expect.
The Genny Projects I have done always started with Building & Fire Department Staff (to obtain the specifics and code requirements).
Once the specifics are known, next stop is the Planning Division, for the required items per Planning.
Typically, Planning will request images and drawings of the surrounding areas, to determine screening, access, etc., so if you are preparing documents (Plans and Specs), be sure to include the stuff for Planning Division separate to the documents for Building and Fire.
A list of typical documents:
A: Planning Division.
- Scaled Site Plan
- Location Plan (area with Genset)
- Pictures of surrounding area + access points, and closest streets
- Cut sheets for proposed Genset (supplied by vendor). contains elevation drawings, EPA details, Fuel Tank information, specifications, enclosure details, and etc.
B: Building Department Plan Check...
Same as listed in "A", along with:
- Concrete Pad details
- Load / Seismic Calcs for Anchors
- Electrical Single Line, Load Calcs & Panel Schedules
- Electrical Plan(s)
- ATS specifications
C: Fire Department Plan Check...
Same as listed in "A", along with:
- Fuel Tank details
- Pad details describing containment area / curbing
- Fuel refilling equipment and locations
- HAZMAT signage layout drawings + details
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The following is some information per the equipment sizing (FYI)
Sizing of Equipment:
1. Generator...
a: 125 HP 480V 3 Phase Motor = 129.6 KVA,
b: 30 HP 480V 3 Phase Motor = 33.2 KVA,
c: Control System Transformer = 10.0 KVA
Total KVA: 172.8 KVA (figure at 173 KVA).
A 175 KW Genny has an Apparent Power rating of 219.0 KVA, at 0.8 Power Factor.
This will cover all three loads at rated capacity.
Next larger size Genny would be 200 KW, with an Apparent Power rating of 250.0 KVA, across a Power Factor of 0.8 (80%).
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2. ATS...
ATS will need to be sized per the total LRA (Locked-Rotor Amperes) of the connected Equipment.
The 125 HP Motor would have minimum LRA of 936 Amps.
The 30 HP Motor would have minimum LRA of 240 Amps.
Total LRA = 1176 Amps.
Minimum capacity for the ATS is 1200 Amps (along with the Service capacity for this setup).
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Long-Winded Warning...
The following relates to oversize generator capacity and Generator basic operation, which may be dismissed.
********** Oversize Genny for extended Locked-Rotor Compensation **********
Genny (Generator) capacity for LRA of both Motors:
LRA for the 30 HP Motor and the 125 HP Motor combined = 1176 Amps.
Locked-Rotor KVA = 935.0 KVA.
Including the Control Transformer: 945.0 KVA.
800 KW Genny has Apparent Power capacity of 1,000 KVA at 0.8 Power Factor.
Debate if Genny capacity must include Locked-Rotor KVA, and at what Percentage (25%, 50%, 100%).
I would like to discuss this issue, in detail.
Motors at Locked-Rotor do draw high Amperes; but do they draw equivalent HP; more precisely, up to 600% more KW s, than the rated Horsepower's input true Power - in KW.
Simply stated, does a 125 HP Motor draw > 468 KW from the Supply at Locked-Rotor (or from Locked-Rotor to a stablized output speed), or is the input KW max'd out around 78 KW.
The Apparent Power may easily be in the 750 KVA range at Locked-Rotor, that is because the Power factor is so extremely low.
Some Building Departments are fine with Gennys at +25% the full load, others want the Genny to cover the full Locked-Rotor draw - in KVA, which translates to a very large Prime Mover + Alternator for the Genset.
This also brings in a larger Fuel Tank, Pad base, Enclosure, etc.
Generators produce Kilo Watts, which translates to usable Horsepower at the shaft of the connected Electric Motor.
The Prime Mover (for example, the Diesel Motor driving the connected AC Alternator), is sized in Horsepower, equivalent to the Kilo Watt Output rating of the Genset (complete Generator apparatus).
Exceeding the KW rating of the Alternator causes the Prime Mover to "Bog Down", but not stall.
A Genset will produce rated output KW (some up to 130% rated KW), and that is it!
The HP rating of the Prime Mover limits the total output, so once that value has been met, that is all you get!
A good example:
Short Circuit the output of the Alternator, by creating a 3 Phase Bolted connection (physically bolt all 3 phases together).
Start the Prime Mover. The Prime mover will run at full speed, developing close to rated HP, but will not stall.
All comments are welcome.
Scott
