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# Power consumption of fan at increased voltage4

## Power consumption of fan at increased voltage

(OP)
Hi,
Do you know what the power consumption of the 624HH Papst fan is at voltages from 18-30V?

624HH fan
https://img.ebmpapst.com/products/datasheets/DC-ax...

Its rated 18-28V, but we intend to run it mainly at 30V. The boss says so.
(we only know it draws 3.6W at 24v input)

### RE: Power consumption of fan at increased voltage

It's going to draw the power that the load demands, up to the point where it can't deliver it. Varying the voltage varies the point where it can't deliver it. Higher voltage increases the probability of the failure mode being the smoke coming out as opposed to just slowing down.

### RE: Power consumption of fan at increased voltage

This statement "With electronic locked-rotor and overload protection" indicates this is probably a "brush-less DC motor", that uses electronics to switch between poles.

Power consumption change with voltage change really depends on what sort of brushless controller is provided, as the electronics that do brush switching could be a constant speed, or speed proportional to voltage. The load is a fan so Fan Laws apply.

Running a motor rated for 28 Volts at 30 volts is possible, but you run a risk of letting the magic smoke out.

Type
624 HH
Nominal voltage VDC 24
Nominal voltage range VDC 18 .. 28
Speed (rpm) min -1 8200
Power consumption W 3.6
Air flow m3/h 56 (free air)

### RE: Power consumption of fan at increased voltage

Well given that it says the acceptable voltage is 18 to 28V you can only assume that it is a fixed speed motor. Others the amount of air flow could change to 50% less than the stated air flow.

So power will remain the same within 10% as nothing is that accurate at 3.6W...

Also the fan curve don't give you the power curve so it will depend on flow and dP across the fan.

Is it really that important to know??

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

### RE: Power consumption of fan at increased voltage

(OP)

#### Quote (LittleInch)

Is it really that important to know??
Thanks, yes because we need to drive two of them from a TPS54070, which has a peak current limit of 0.6A, so if the 2 fans draw too much current , then the buck wont be able to supply them. Vin is 31-36V. (To the buck)

### RE: Power consumption of fan at increased voltage

Papst DC fans are now all ECMs, Electronically Commutated Motors, meaning it is basically a PMDC motor with a “drive” built inside. The motor is designed for 18VDC, the electronics provide that via PWM regardless of the input voltage being up to 28VDC. Applying excess voltage will not increase the speed, however it will shorten the life of the electronics. They give you a maximum voltage rating for a reason. Power consumption will likely be slightly higher as the drive heats up due to the higher voltage.

" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

### RE: Power consumption of fan at increased voltage

Electronically Commutated Motors, meaning it is basically a PMDC motor with a “drive” built inside.

I think one would call it a "brushless DC motor". A permanent magnet DC motor has brushes.

### RE: Power consumption of fan at increased voltage

Semantics. It is a motor designed to run on DC and has no brushes because it uses permanent magnets. So Permanent Magnet DC….

" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

### RE: Power consumption of fan at increased voltage

Sure its semantics, but but a PMDC motor has meant a brushed motor since motors were invented, long before electronic controls. Semantics is what allows people to understand what you are saying.

### RE: Power consumption of fan at increased voltage

(OP)
Thanks, a PMDC is a type of brushless motor...but may also be a term used for a brushed one, i dont know.
And now i am ashamed of myself, because there is (generally) a difference between a PMDC and a BLDC, and i have forgotten it....

I think a PMDC has sinusoidal air gap field, but a BLDC has trapezoidal air gap field?

### RE: Power consumption of fan at increased voltage

PM = "permanent magnet"
BL = "brushless"

A normal permanent-magnet conventional DC motor has a fixed permanent-magnet stator and a wound-rotor with a commutator and brushes. It can be fed plain ordinary DC power from a battery without any fancy schmancy electronics involved, and work.

A normal brushless motor has a permanent-magnet rotor and a wound stator which has to be fed AC in order to work. It is not a DC motor at all - it is an AC synchronous motor with an electronic controller that serves the commutating function (to chop up DC into the AC that the windings need in order for them to work. Viewed as a complete assembly together with the electronic controller that makes it work, that's how it looks like a DC motor.

### RE: Power consumption of fan at increased voltage

> I think a PMDC has sinusoidal air gap field, but a BLDC has trapezoidal air gap field?

I think that's true. But the details are a bit muddy to me.

https://www.motioncontroltips.com/faq-trapezoidal-...

#### Quote:

Another way to classify motors is by their back EMF profile. BLDC motors are referred to as trapezoidal motors, since they produce trapezoidal back EMF, and BLAC motors (aka PMSM) are referred to as sinusoidal motors since they produce sinusoidal back EMF. But, as discussed below, the back EMF of a BLDC motor is not truly trapezoidal in shape. In reality, its shape is more sinusoidal. This is why BLDC motors can use trapezoidal or sinusoidal commutation.

=====================================
(2B)+(2B)' ?

### RE: Power consumption of fan at increased voltage

(OP)
Thanks, Apologies to CompositePro...."PMSM" is what i confused with "PMDC"

### RE: Power consumption of fan at increased voltage

the fan will only be able to drain the power at which the load demands. It can not have to waste the other power.

### RE: Power consumption of fan at increased voltage

If use a buck converter with TPS54070 why not reduce output voltage to maximum specified - 28V or even lower?
TPS54070 have current limit also, so may add current protection.

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