Motor Overload

[whazza22]

What should the overload be set to for a three phase 0.5kW motor?

 

[davelerave]

you need the nameplate fla preferably as the calculated amps doesnt always match depending on efficiency etc

 

[mechelec]

0.85 amps assuming a power factor of 0.85

 

[whazza22]

How did you get that answer mate?

I dont have any details other than the kW.

 

[davelerave]

0.85 amps assuming a power factor of 0.85

efficiency when factored in will increase that figure

 

[dichroic]

What should the overload be set to for a three phase 0.5kW motor?

500 watts / (1.732 x 400v x 0.8) = 0.9 amps approx

This has not factored in the efficiency of the machine which will not be 100% obviously so set the overload at 1.0 amps.

Regards

Dichroic

 

[JamieR]

overload

 

[mechelec]

overload

overloads are usually set to the full load current of the motor

 

[StokieSpark]

500 watts / (1.732 x 400v x 0.8) = 0.9 amps approx

This has not factored in the efficiency of the machine which will not be 100% obviously so set the overload at 1.0 amps.

Regards

Dichroic

HI, can you tell me where you get the 0.8 figure from and what it is, thanks, Matt.

 

[silva.foxx]

Assuming it's a DOL and not on an inverter...

Approx 1.23 A if 415v 0.55kw 2-pole.
Approx 1.58 A if 415v 0.55kw 4-pole.

http://www.brookcrompton.com/pdf-files/2100e_waluminium_v3e.pdf page 4, perhaps.

How do you know it's wattage?
From a schematic?
Is it correct?
Has a different sized motor been fitted since?
Speed?

 

[davelerave]

HI, can you tell me where you get the 0.8 figure from and what it is, thanks, Matt.

(power factor) the wattage divided by the 0.8 (if accurate)gives you the VA

 

[Guest123]

HI, can you tell me where you get the 0.8 figure from and what it is, thanks, Matt.

The 0.8 figure is the power factor associated with the motor, it's usually found on the rating plate.