DIRTY COIL EFFECTS ON MOTOR AMP. 1

[naifmbo]

WILL DIRTY AHU'S COIL INCREASES OR DECREASES MOTOR AMPERS DEU TO LOWER AIR FLOW.

 

[quark]

Dirty coil(air side) generally creates restriction to the air flow and thus reduces it. In this case the current drawn by the motor should reduce.

But, if your coil sealing at the periphery is really bad, there may be increased bypass flow around the coil and your motor may draw more amps. This may happen in some cases.

Regards,

 

[HVAC68]

Dirty coil would mean a higher static or resistance imposed on the fan and hence a higher power consumption. Is this line of arguement right ???

HVAC68

 

[McCormick93]

When air flow is restricted, the fan is moving less air, therefore doing less work, consuming fewer horsepower and motor amps. High static pressure does not "block" the fan and make it work harder (as many believe), it just swirls more air around in the housing, which takes almost no work at all.

 

[MintJulep]

It depends.

On the type of fan, its characteristic curve, and where on the curve you are operating.

For a typical backwards-curved blower, operating in the stable region of its performance, quark and McCormick are correct.