Sizing a service with a Fire Pump

Status
Not open for further replies.
Joethemechanic

Joethemechanic

Senior Member
Location
Hazleton Pa
Occupation
Electro-Mechanical Technician. Industrial machinery
Ok, they say the reason for the overload is for short circuit protection.


If you lock the rotor of a fire pump, and supply it with LRA, how long (time) does the motor have to last?


In a funny kind of way, it almost seems like a high rotor resistance would be advantageous. With an impeller designed to provide the desired P-V curve with the somewhat increased slip.
 
O

Open Neutral

Senior Member
Location
Inside the Beltway
Occupation
Engineer
cadpoint said:
MH Newsletters

Article 695 (bottom of page)
Click to expand...


Re: Run No Matter What...
Warships had/have "battleshort" panels that would be used when in a firefight. They'd rather have the wiring to a main turret catch fire than fail to rotate/discharge weapons.

NASA MSFC also had same at Mission Control; they would enable them during critical intervals, esp. when the LM was descending to land and ascending. Like the Navy, the alternative was on-the-scene firefighters.
 
Lady Engineer

Lady Engineer

Senior Member
Location
New Jersey
bob said:
You don't size the conductor for the LRA. It is sized at 1.25 x the FLA of the motor and other equipment.
The service is installed in conduit with 2" of concrete around it(I think it is 2").
It is then considered outside the building so there is no disconnect required. The OC breaker comes with the fire pump and its other equipment. You can see this in the picture at his site.

http://ecmweb.com/nec/code-basics/electric_power_pump/
Click to expand...

The OCP is usually just the controller.

Now, I guess all I wanted to know if I can tap it, with the service. They do indeed have a 600A service, but they are only drawing 67A right now. Wow...what utility would give them 600A?
 
Status
Not open for further replies.
Top