Measuring power output by modified prony brake

AI Thread Summary
The discussion revolves around measuring power output from a water wheel using a modified Prony brake method. The user connects a pulley system to a DC motor, which is controlled by a potentiometer acting as a brake. They find that their calculated power output is lower than that obtained from the Prony brake method, leading to confusion about their calculations. A participant suggests that mechanical losses in the pulley system could be a factor affecting the results. The conversation highlights the importance of considering mechanical efficiency when measuring power output.
Helmizar
Messages
1
Reaction score
0
Hi guys

I have problem, basically I want to measure the power output from a water wheel.
so basically I measured the power output by connecting the pulley that attach on the shaft of the water wheel. then this pulley is connected to other pulley which sit on the shaft of the DC motor.
this DC motor is braking by using potentiometer as controller (which act as brake to the wheel). may be much more easy to see the drawing http://www.thescienceforum.com/images/smilies/smile.png
currently I calculate the power output by using method as shown in the attachment. but when I compared it with prony brake method, the power output is smaller than prony brake method. I get confuse now, is there any suggestion regarding my equation, probably something wrong with my calculation method
Helmizar
 

Attachments

  • for forum.png
    for forum.png
    23.3 KB · Views: 642
Last edited by a moderator:
Engineering news on Phys.org
Could it just be due to mechanical losses in the pulley system?
 

Thread 'Race car suspension Class'

Posted June 2024 - 15 years after starting this class. I have learned a whole lot. To get to the short course on making your stock car, late model, hobby stock E-mod handle, look at the index below. Read all posts on Roll Center, Jacking effect and Why does car drive straight to the wall when I gas it? Also read You really have two race cars. This will cover 90% of problems you have. Simply put, the car pushes going in and is loose coming out. You do not have enuff downforce on the right...
View full post »

Thread 'Cantilever help'

I'm trying to decide what size and type of galvanized steel I need for 2 cantilever extensions. The cantilever is 5 ft. The space between the two cantilever arms is a 17 ft Gap the center 7 ft of the 17 ft Gap we'll need to Bear approximately 17,000 lb spread evenly from the front of the cantilever to the back of the cantilever over 5 ft. I will put support beams across these cantilever arms to support the load evenly
View full post »
Thread 'What's the most likely cause for this carbon seal crack?'

Thread 'What's the most likely cause for this carbon seal crack?'

We have a molded carbon graphite seal that is used in an inline axial piston, variable displacement hydraulic pump. One of our customers reported that, when using the “A” parts in the past, they only needed to replace them due to normal wear. However, after switching to our parts, the replacement cycle seems to be much shorter due to “broken” or “cracked” failures. This issue was identified after hydraulic fluid leakage was observed. According to their records, the same problem has occurred...
View full post »

Similar threads

Gearbox with single input, double output (at different RPM)
Replies
10
Views
2K
Ideas welcome on how to attach 2 shafts of different diameters
Replies
17
Views
4K
Automotive How to calculate hydraulic disc brake size using actuation force?
Replies
15
Views
6K
Automotive Poor Man's Hydrostatic drive: power steering pump as motor?
Replies
19
Views
3K
Automotive Determining the Brake Caliper Force for a Car
Replies
6
Views
8K
Small Engine Dyno: Designing & Attaching Torque Arm
Replies
8
Views
11K
Measuring Power output of DC generator
Replies
38
Views
4K
What is the Required Torque for Moving a 20 kg Weight with a 10 cm Crank?
Replies
5
Views
2K
How to Measure Torque Required for motor to spin a rotating shaft?
Replies
3
Views
4K
How do you calculate the energy stored in a power spring?
Replies
2
Views
3K

Hot Threads

Recent Insights

Back
Top