Cost of losses in a motor
Cost of losses in a motor
(OP)
I was reading an interesting article about the use of High Temperature Superconducting material used in motor as opposed to the commonly used copper. The article went onto talk about the operating cost savings of the motor due to the decrease in losses that are seen with copper wound motors.
The article stated that a 5,000hp motor operated run 24hrs/day 7 days a week would have a savings of $50,000/year as a result of lessened losses due to copper.
I found this cost savings statement to be interesting, for I never realized that the losses associated with operating larger motors cost that much. I know this cost is dependent on a number of motor variables, but overall for larger motors above 1,000 hp is there that much of a cost associated with electrical losses in a motor run constantly throughout the year? Does the number stated in the article of about $50,000 per year seem right?





RE: Cost of losses in a motor
5000 hp ~ 3000 kw
3000*24 = 72000 kwh/dy
72000*365 = 26280000 kWh/yr
@ $.08/kWh = $2,102,400 running cost
Now with a 1% improvement in efficiency - 2102400*.01 = $21,024 savings annually.
If they could make a motor 2% more efficient and the cost of electricity is $0.12/kWh then $50,000/year savings might be possible. Mind you, we are talking about a 3MW motor.
------------------------------------------------------------------------
If it is broken, fix it. If it isn't broken, I'll soon fix that.
RE: Cost of losses in a motor
<<A good friend will bail you out of jail, but a true friend
will be sitting beside you saying " Damn that was fun!" - Unknown>>
RE: Cost of losses in a motor
Even though induction motors are pretty efficient, motor losses are a sizable portion of all energy losses in industrialized countries. So they are a favorite target for anyone with the next great idea.
RE: Cost of losses in a motor
I found the article interesting because I never really realized how much money was associate with losses. I know effeciency is made up of both electrical and mechanical losses and the electrical losses are mostly in the form of heat from the resistance of the windings. It made me begin to wonder if there was anything that can be done on existing copper motors to reduce the electrical losses. I know the mechanical losses are probably more easy to decrease however I was just trying to think outside the box to see if there is any way to reduce electrical losses in some of our larger motors.
RE: Cost of losses in a motor
Keith Cress
kcress - http://www.flaminsystems.com
RE: Cost of losses in a motor
From a course on improving motor efficiency I took a few years ago sponsored by EPRI;
So of all those, if you could somehow use the not-yet-existent super conductor in both the stator and rotor, you could reduce a percentage of 60% of the losses. Lets say we pick a 5000HP (3730kW) high efficiency motor that is 95% efficient (not unheard of). That means the total losses are 186.5kW, of which 111.9kW are from copper losses. If you manage to cut that by only 80%, you save 89.5kW, for 8760 hours/year, so that comes to about 784,195kWH/yr. At $0.12/kWH, that comes to about $94,000.00... sweet!
I won't hold my breath though...
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: Cost of losses in a motor
With super conductors you won't need fans to cool the motor. Actually air flow across the windings would be counter productive. The super conductors would work better in a vacuum. Windage losses will probably be replaced by the expense of running a vacuum pump.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Cost of losses in a motor
I agree with the stator losses, I would expect 2-3% savings there.
Not so sure you can use superconductors in the rotor. Doesn't the rotor require some resistance to create the starting torque and not draw a huge locked rotor current? If I'm thinking about that right, you'd have to use a VFD to start the motor which would negate the savings if it was run continuously. Of course, it could be bypassed once running.
RE: Cost of losses in a motor
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Cost of losses in a motor
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies
RE: Cost of losses in a motor
------------------------------------------------------------------------
If it is broken, fix it. If it isn't broken, I'll soon fix that.
RE: Cost of losses in a motor
RE: Cost of losses in a motor
Keith Cress
kcress - http://www.flaminsystems.com
RE: Cost of losses in a motor
Chris
"In this house, we obey the laws of thermodynamics." Homer Simpson