power factor of inline fans

psychedelicdaddi

psychedelicdaddi

Well-Known Member
hey guys, not that this is really a big deal to anyone, but i was wondering if anyone ever adds an AC capacitor bank to their inline fans to reduce the reactive power. I would assume i just add a cord to some 240-480vac caps in parallel and plug it in the outlet that the fan is on. Just watch the current drop as i add more caps until its lowest value before it turns capacitive reactive and pat myself on the back yea?
 
psychedelicdaddi

psychedelicdaddi

Well-Known Member
OldMedUser said:
As I know nothing about this what is the purpose of it?
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So the magnetic losses of the motor contribute to the power consumption of the machine just like the amount of current passing through. So you know there's two kinds of power in the motor, resistive (wire) and inductive (magnetic). To cancel out the magnetic losses i can supply an extra electric field in the form of a capacitor bank, i think. Then it would just look like a pure resistive load and very little phase shift between the AC supply and the motor load. In turn, max efficiency on the motor. (again, i think)
 
nfhiggs

nfhiggs

Well-Known Member
PSUAGRO. said:
if it's induction ac motor & run at full load, then it's efficiency/pf should be high already?IDK, I'm not an electrical engineer......

who might know better
@nfhiggs
@Randomblame
@1212ham
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For small loads like an inline fan, I don't see the point. At best you're talking a few watts potentially saved - pennies per month.

Power factor is something industrial places running multi-kW motors and pumps need to think about, but residential customers... not so much.
 
PSUAGRO.

PSUAGRO.

Well-Known Member
nfhiggs said:
For small loads like an inline fan, I don't see the point. At best you're talking a few watts potentially saved - pennies per month.

Power factor is something industrial places running multi-kW motors and pumps need to think about, but residential customers... not so much.
Click to expand...
thanks..............much appreciated
 
Randomblame

Randomblame

Well-Known Member
psychedelicdaddi said:
So the magnetic losses of the motor contribute to the power consumption of the machine just like the amount of current passing through. So you know there's two kinds of power in the motor, resistive (wire) and inductive (magnetic). To cancel out the magnetic losses i can supply an extra electric field in the form of a capacitor bank, i think. Then it would just look like a pure resistive load and very little phase shift between the AC supply and the motor load. In turn, max efficiency on the motor. (again, i think)
Click to expand...
Here is an useful article about power factor correction for electro motors:

https://blog.schneider-electric.com/power-management-metering-monitoring-power-quality/2017/12/06/3-safety-measures-motors-individual-power-factor-correction/

BTW,
If the fan is relatively new, he should already have a protection circuit with PFC, as it has been mandatory for some years.
 
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