Maker Pro
Maker Pro

help with power consumption.

zms

Apr 29, 2016
17
Joined
Apr 29, 2016
Messages
17
I need to determine the power consumed by a machine tool in kwh.

while checking out the spec-sheet of an automatic lathe i found that nowhere on the list was the mention of the power consumed in kwh, but rather it was mentioned that the lathe used a 2.5 hp motor.

so from this would it be safe to arrive upon this kind of calculation.

2.5 hp = 1.864 kw.

if the machine is run for one hour then, consumption is : 1.864 kw x 1 hr = 1.864 kwh.

Is the above calculation correct ? if so do correct me please.
 

zms

Apr 29, 2016
17
Joined
Apr 29, 2016
Messages
17
note: the 2.5 hp of the motor is the mechanical power of the motor.
 

Harald Kapp

Moderator
Moderator
Nov 17, 2011
13,700
Joined
Nov 17, 2011
Messages
13,700
note: the 2.5 hp of the motor is the mechanical power of the motor.
The electrical power will be higher due to losses in the motor. Unfortunately I don't know by how much. The most precise method wil be to use a power meter in the electrical connection and measure real power used.
Note that it is insufficient to measure the current as in AC the phase difference between voltage and current as introduced by the inductance of the motor also plays an important role. A good power meter will take this into account and show real power as well as apparent power.
 

duke37

Jan 9, 2011
5,364
Joined
Jan 9, 2011
Messages
5,364
The power will be less than the maximum motor power, it depends on the work the lathe is doing. Is it turning balsa wood or machining stainless steel?
 

BobK

Jan 5, 2010
7,682
Joined
Jan 5, 2010
Messages
7,682
There must be a voltage and current rating for the motor. The power is the product of the two.

Bob
 

duke37

Jan 9, 2011
5,364
Joined
Jan 9, 2011
Messages
5,364
There must be a voltage and current rating for the motor. The power is the product of the two.

Bob
No, the power is the product of the voltage, current and the power factor.
The motor rating does not say what power is actually used.
The power factor will be high when the motor is heavily loaded but low when it is lightly loaded.
 

BobK

Jan 5, 2010
7,682
Joined
Jan 5, 2010
Messages
7,682
True. The product will give the max power used.

Bob
 
Top