Neutral with 3 phase Cooling tower

Status
Not open for further replies.
Lady Engineer

Lady Engineer

Senior Member
Location
New Jersey
Don't let the P.E. fool you, there are things I still need to be schooled on, and I am willing to ask. ;)

It appears that I'm reviewing plans for a friend, and the engineer ran 4#6 and a ground to the Cooling tower. Now the Cooling Tower does have a VFD also, so I do understand why they would run a neutral, per se, however in your honest opinion, do you think it's necessary since the panel feeding the Cooling Tower has a neutral?

Your take and advice is much appreciated! :)
 
david luchini

david luchini

Moderator
Staff member
Location
Connecticut
Occupation
Engineer
I can't see any reason why a VFD would require a neutral. I'd imagine it derives it's own control power from an internal CPT.
 
qcroanoke

qcroanoke

Sometimes I don't know if I'm the boxer or the bag
Location
Roanoke, VA.
Occupation
Sorta retired........
Lady Engineer said:
Don't let the P.E. fool you, there are things I still need to be schooled on, and I am willing to ask. ;)

It appears that I'm reviewing plans for a friend, and the engineer ran 4#6 and a ground to the Cooling tower. Now the Cooling Tower does have a VFD also, so I do understand why they would run a neutral, per se, however in your honest opinion, do you think it's necessary since the panel feeding the Cooling Tower has a neutral?

Your take and advice is much appreciated! :)
Click to expand...

I'm not sure I understand what you are asking.


however in your honest opinion, do you think it's necessary since the panel feeding the Cooling Tower has a neutral?
Did you mean:
however in your honest opinion, do you think it's necessary just because the panel feeding the Cooling Tower has a neutral?
 
B

BJ Conner

Senior Member
Location
97006
May Be They didn't know?

May Be They didn't know?

Lady Engineer said:
Don't let the P.E. fool you, there are things I still need to be schooled on, and I am willing to ask. ;)

It appears that I'm reviewing plans for a friend, and the engineer ran 4#6 and a ground to the Cooling tower. Now the Cooling Tower does have a VFD also, so I do understand why they would run a neutral, per se, however in your honest opinion, do you think it's necessary since the panel feeding the Cooling Tower has a neutral?

Your take and advice is much appreciated! :)
Click to expand...

I've done jobs where the architech,and/or mechanical engineers didn't know anything but "yes there will be a cooling tower". AND "your drawings are due the day after tomorrow." AND "NO I can't get any vendor drawing to you for 3 weeks, were still evaluating the system."
I'de put in 4 wires and if I remembered and had time the usual CMA statement for the contractor to check the vendor drawings.
Contractors are usually happier to leave a conductor than to have to add one that wasn't on their bid drawings.
 
charlie b

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
Every drawing I issue that shows power to a three phase motor that has a VFD will show a 3 wire feeder plus an EGC. Many times, the panel feeding such motors does not have a neutral. But even if it did, that would not change the situation.
 
Status
Not open for further replies.
Top