Blower motor amperage draw

[kbs]

Squirel cage type blower wheels can have forward curve vanes or reverse curve vanes. Will the fan motor amperage react the same for each if the suction side damper closed tight?

 

[MintJulep]

Mostly.

 

[kbs]

Thanks MJ. We have a 7.5hp roof top unit tripping it's overload protection. The electricians determined there is no problem with the motor and I heard them discussing possible damper issues. The discussion became somewhat animated (ans amusing) as one fellow was adamant the amp reading would drop in either case and the other fellow was as adamant the amp draw would go up in a forward curve wheel. Thanks.

 

[jkauwale]

Hi kbs, you should take a look at the fan curve of your fan. At various operating points, the fan's efficiency and therefore power usage may change. How much it will change is dependent on your fan.

Justin K, P.E.

http://www.engproguides.com