direct drive / belt drive exhaust fan

[MSHEHRI]

hello every one

I have issue,
2 suppler providing exhaust fan with belt drive motor but the specification say its must be direct drive
and thye tolled me according to big capacity we canot go through direct drive
L/S 7950 SP 550 Pa?
please advise

thanks

 

[willard3]

You will have to talk to other suppliers.

 

[MintJulep]

Option 1: Find a supplier willing to provide what is specified.
Option 2: Request a change order to the specification so that you can provide what is available.

 

[MSHEHRI]

thanks gentleman ,

my question is ,there limit for direct drive fan capacity ?
is it available only for small air flow?

 

[317069]

specification usual mention equipment brand and model with word "or equal", what is in your specification.

 

[EnergyProfessional]

Who specified direct drive? i use a basis of design fan or other device and make sure it actually exists.

you can specify a car that gets 200 mpg and goes 0-60 in 3 seconds while seating 10 passengers and pulling a trailer..

 

[Compositepro]

The larger the fan, the lower the operating rpm will be. Direct drive means the fan operates at motor rpm, which will be too fast for a large fan.

 

[willard3]

This again depends upon the maker. There are very large direct drive fans that run on low rpm motors. This is not common

 

[MSHEHRI]

thanks gentleman

last meeting with suppler said , impossible to manufacture direct drive fan with the large air flow L/S 7950 SP 550 Pa?

 

[317069]

and what did you answer him?

 

[chicopee]

So how much horsepower are we looking at for each motor?

 

[urgross]

Or maybe specify a fan wall.

 

[RossABQ]

So how much horsepower are we looking at for each motor?

About 8 HP, it's 17,000 cfm at 2.25" in round numbers. Figure a 10 HP nameplate motor.

What the vendor is saying is, We don't make that fan.

 

[trashcanman]

So use 2 or more direct drive fans in parallel.

 

[dbill74]

Aside from what the spec says, is there some reason the fan needs to be direct drive? I.E. Space.
If the fan meets all other specified criteria (centrifugal, upblast, inline, etc) and fits in the allocated space, use the belt drive fan.

 

[RossABQ]

Is this a roof-mounted fan? Many specs require direct drive because of client desire to eliminate work on the roof, where OSHA has some pretty stiff requirements.

 

[urgross]

I've used up to 4 direct drives in a fan wall.