# DC MOTOR DRIVE

Discussion in 'Homework Help' started by segecious, Mar 4, 2015.

1. ### segecious Thread Starter New Member

Nov 6, 2014
7
0
A motor \$10,000 is used for group in a certain installation. How will its total annual cost compare with the case where four individual motors each costing \$4000 were used. With group drive, the energy consumption is 50kwh whereas it is 45kwh for individual drive. the cost of electric energy is 20k/kwh. Assume depreciation, maintenance and other fixed charges at 10% in the case of group drive and 15% in the case of individual drive.

Solution: group drive

Capital cost =\$10000

Annual depreciation,maintenance and other fixed charges 10% of \$10000=\$1000

Annual cost of energy=\$(50,000*0.2)=\$10,000

Total annual cost=\$(1000+10,000)=\$11,000

Individual drive

Capital cost=4*\$4000=\$16,000

Annual depreciation,maintenance and other fixed charges

15%of\$16,000=#2400

Annual cost of energy=\$(9000+2400)=\$11400

did i get it?

2. ### Dodgydave Distinguished Member

Jun 22, 2012
4,986
745
We dont know,did you?

3. ### JoeJester AAC Fanatic!

Apr 26, 2005
3,373
1,159
I'd say you missed it.

The stem is the annual costs ....

You can figure out the costs per kWh. You know how many hours are available per year. You can figure the annual costs of generating the electricity.

Then add in the lumped costs of the maintenance etc.

4. ### segecious Thread Starter New Member

Nov 6, 2014
7
0
• what should i do to solve this question?pls assist

5. ### JoeJester AAC Fanatic!

Apr 26, 2005
3,373
1,159
You have multiple costs

The 10k and the 12k which is depreciated annually ... The depreciation is one cost, but the problem gave the generic label includind the other costs.

So ... The first cost is the calculated depreciation.

The second cost is the cost to produce the energy.

Remember, there atr two systems you are comparing. Put one in column a and the other in column b.

Track your units so you are clear and concise in your calculations.

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Last edited: Mar 15, 2015