BasuSiddha23 wrote:Regarding transmission lines, what type of information should you know about the voltages, resistance, power, etc.?
Does anyone know a reliable source to find energy production percentages?(like what percentage hydroelectric or wind accommodates for the world energy production)

Every formula pertaining to current, voltage, resistance, amperage, etc. Make sure you have a comprehensive formula sheet so you can answer those questions correctly. You should know the different types of transmission lines (primary, secondary, etc.).

Re: Wind Power B/C

Posted: April 20th, 2017, 2:23 pm

by Anomaly

Does anyone know what formulas in particular that can be used for wind power?

Re: Wind Power B/C

Posted: April 20th, 2017, 3:51 pm

by windu34

Anomaly wrote:Does anyone know what formulas in particular that can be used for wind power?

V=IR
Honestly you just have to know them all so just find physics formula sheets amd then go after wind power specific ones

Re: Wind Power B/C

Posted: April 23rd, 2017, 9:13 pm

by windu34

Does anyone know to even approach solving this? I might just not be familiar with the equation:

The power generated by a turbine is 18,000 Watts. If the wind speed, which is initially 30 m/s decreases by 25%, what must the lift force be in order to generate the same amount of power?

800 N

Re: Wind Power B/C

Posted: April 23rd, 2017, 10:03 pm

by windu34

Apologies for the double post, but could use another opinion on this one as well:

A 36% efficient coal power plant burns 8.5 million kilograms of coal in a day. (Assume the heat of combustion of coal is 31 MJ/kg) How many watts of power is produced per day?

I got 95 TW
Answer key says 1.1 GW

Re: Wind Power B/C

Posted: April 24th, 2017, 4:32 am

by maxxxxx

windu34 wrote:Does anyone know to even approach solving this? I might just not be familiar with the equation:

The power generated by a turbine is 18,000 Watts. If the wind speed, which is initially 30 m/s decreases by 25%, what must the lift force be in order to generate the same amount of power?

The question you quoted in your first post has been answered on an earlier page, but I think we decided it was a badly worded question.

windu34 wrote:Apologies for the double post, but could use another opinion on this one as well:

A 36% efficient coal power plant burns 8.5 million kilograms of coal in a day. (Assume the heat of combustion of coal is 31 MJ/kg) How many watts of power is produced per day?

I got 95 TW
Answer key says 1.1 GW

You calculated the joules produced per day, but you need to divide it by the number of seconds in a day to find the power produced.

Re: Wind Power B/C

Posted: May 13th, 2017, 5:59 pm

by wzhang5460

RestingDoll wrote:

daydreamer0023 wrote:What would be considered to be a "great score" for blades in millivolts for Division C, given that a good score would get you placing in the top 10 in nats? I know things have changed since last year, but I kind of want to get a better estimate of how I (belatedly) did last year and what to improve upon this year. Thanks in advance!

Edit: How does the width of a blade affect performance in general in your experiences?

Every competition will have different scores in terms of voltage due to differences in motors/fans/resistance. As long as you do relatively well compared to others, you should be fine. Specific to last years nats, I think 1st place got 650 mV on high power and 450 mV on low power (check old forums).

Do you happen to know what the resistance was?

Re: Wind Power B/C

Posted: May 13th, 2017, 6:41 pm

by daydreamer0023

wzhang5460 wrote:

RestingDoll wrote:

daydreamer0023 wrote:What would be considered to be a "great score" for blades in millivolts for Division C, given that a good score would get you placing in the top 10 in nats? I know things have changed since last year, but I kind of want to get a better estimate of how I (belatedly) did last year and what to improve upon this year. Thanks in advance!

Edit: How does the width of a blade affect performance in general in your experiences?

Every competition will have different scores in terms of voltage due to differences in motors/fans/resistance. As long as you do relatively well compared to others, you should be fine. Specific to last years nats, I think 1st place got 650 mV on high power and 450 mV on low power (check old forums).

Do you happen to know what the resistance was?

It's changed since last year (since now the resistance can be much more), but I suppose it was at 7.5ish ohms because our blade performed better at Nats than at my home setup.

Re: Wind Power B/C

Posted: May 13th, 2017, 6:49 pm

by wzhang5460

daydreamer0023 wrote:

wzhang5460 wrote:

RestingDoll wrote:
Every competition will have different scores in terms of voltage due to differences in motors/fans/resistance. As long as you do relatively well compared to others, you should be fine. Specific to last years nats, I think 1st place got 650 mV on high power and 450 mV on low power (check old forums).

Do you happen to know what the resistance was?

It's changed since last year (since now the resistance can be much more), but I suppose it was at 7.5ish ohms because our blade performed better at Nats than at my home setup.

Oh I see. Our turbine got about 300 mV at States but i don't know what the resistance was.