Running cost of an electric motor

[damscot]

Can anyone give a formula for the running cost of an electric motor from a three phase supply 24/7 for a year

 

[jraef]

watts x hours /1000 = kWh, which is what your utility bills you for.

Methinks you were looking for something else, but of course your question was a little sparse on details. Are you unable to measure the kW consumption? Isn't there a load connected to your motor? Are you looking to estimate cost based only on motor nameplate data? Does your utility penalize you for poor power factor? Are you going to correct your pf? The list goes on and on.

Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[waross]

Well said jraef
damscot, Try browsing this site. This topic was discussed in great detail within the last few weeks.
yours

 

[REDDOG]

Demand 1 Start per month (KW) plus energy (KWHrs)

 

[aolalde]

Damscot.
The requested formula for 1 year motor operation:

E = 1.732xAmps x VoltsLL x PF x 24(hrs) x 365(days)
Cost = E x $(per 1kWH)

E = Total electric energy consumption in 1 year given in kWH.
Amps = average RMS line current of the three phases.
VoltsLL = average RMS voltage line to line(3 phases)
PF = motor power factor on the nameplate or from the motor manufacturer performance data.

Penalties due to maximum demand and excesive low power factor will add some extra cost depending on the utility regulations.

 

[waross]

If the motor is running at less than 100% load, the power factor will have to be determined at actual operating conditions instead of using the nameplate value, unless the power factor has been corrected to 100%.
respectfully