Meaning of Full Load Amperes (FLA)

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• #2

Can you tell us what you mean by FCU, over here (UK) if often means Fused connection unit.

1.1kW and 2.8A works for 400V but it would be unusual for a single phase load to be connected phase-phase.

 

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• #3

FCU: Fan Coil Unit.

But also.... apologies... I will try to modify my thread as it's a 3phase fancoil.

Yet...

1100 / (400 * sqrt 3) should be 1.58 A. Not 2.8 A.
Not sure what I'm calculating wrong.
Thank you

 

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If you look at motor current charts the FLA does state its 2.8A for a 1.1kW motor at 380Vac.

 

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• #5

Spoon said:

If you look at motor current charts the FLA does state its 2.8A for a 1.1kW motor at 380Vac.

Click to expand...

That makes a bit more sense here, as 3-phase load and typical power factor of an induction motor.

 

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• #6

Mark_Djorn said:

FCU: Fan Coil Unit.

But also.... apologies... I will try to modify my thread as it's a 3phase fancoil.

Yet...

1100 / (400 * sqrt 3) should be 1.58 A. Not 2.8 A.
Not sure what I'm calculating wrong.
Thank you

Click to expand...

There is also the Power Factor and Efficiency of the motor that has to be taken into account.

 

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• #7

Spoon said:

If you look at motor current charts the FLA does state its 2.8A for a 1.1kW motor at 380Vac.

View attachment 93410

Click to expand...

Thank you for sharing. But I cannot figure out the maths behind that... ?

 

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• #8

Spoon said:

There is also the Power Factor and Efficiency of the motor that has to be taken into account.

Click to expand...

Correct... even if I wanted to consider 0.8 for both PF and efficiency... I dont get anything grrater than 2.5A.... ?

 

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• #9

Those tables are often a worst-case value for sizing a circuit, if you have a specification for the actual motor you should use it.

 

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• #10

There is the calcs that I pinched from a site.

Motor FLC calculator | Motor Full load current calculator

The motor full load current forms the basis for the selection of switchgear. Here is a motor FLC calculator that calculates the motor full load current.

www.electricalclassroom.com

 

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• #11

Mark_Djorn said:

Correct... even if I wanted to consider 0.8 for both PF and efficiency... I dont get anything grrater than 2.5A.... ?

Click to expand...

Is there no plate on the motor telling you the Efficiency and Power Factor?

 

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• #12

I think my confusion comes from the fact I don't know the definition of FLA or FLC.

Also, have a look at this picture.
I cannot figure out the maths to confirm the current given once I have voltage, power, power factor and efficiency

 

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James

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• #13

I note that the motor is 1.5kw
the fan is 1.16kw

it is normal for the motor to be slightly higher rated than the fan as it prevents the motor from being run in a slightly overloaded state and therefore overheating.

the motor itself will have a nameplate that shows the full load current.

 

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• #14

James said:

I note that the motor is 1.5kw
the fan is 1.16kw

it is normal for the motor to be slightly higher rated than the fan as it prevents the motor from being run in a slightly overloaded state and therefore overheating.

the motor itself will have a nameplate that shows the full load current.

Click to expand...

For some reason I thought that a fancoil only had 1 motor: the fan. But ot seems that this plate differentiates between motor AND fun. Not sure to understand the difference. But if I put some numbers is.... 1.5 kW; 400V; 0.83 eff; maybe a 0.8 PF... we will get more or less the 3.42 A stated.
Also, I can see that my Single Line Diagram only reported the rating of the fan (1.1 kW) but the FLA of the motor it seems.

Question is... if not the fan, what's the motor doing in a Fancoil?

 

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• #15

The motor converts electrical energy to a rotating force (speed x torque=power)
the fan converts the rotation to a forward flow of air or other fluid.

what are you trying to figure out?
wiring, suitable motor overload etc?

 

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