## Braked dyno project

## Braked dyno project

(OP)

Hello I`m working on a braked dyno build, I`m using 2 eddy current brakes with load-cells and a NI DAQ.

I`m getting a bit of mess with the software.

Is possible to calculate the power output, knowing the braked torque and the acceleration rate?

Regards

I`m getting a bit of mess with the software.

Is possible to calculate the power output, knowing the braked torque and the acceleration rate?

Regards

## RE: Braked dyno project

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

## RE: Braked dyno project

## RE: Braked dyno project

- Steve

## RE: Braked dyno project

## RE: Braked dyno project

- Steve

## RE: Braked dyno project

Steady with a constant torque reading is hard to get in a short time so if I want to get a lot of points it take time, I have to figure out a lot yet.

I have to calculate coast down to get a estimated flywheel power, but I like to solve before wheel numbers.

## RE: Braked dyno project

torque = inertia x dN / (308 x dt)

or

P = (inertia x N2^2/2 - inertia x N1^2/2) / dt

Where,

dN is the change is speed

dt is the change in time.

You then have to add this to the eddy brake torque or power.

## RE: Braked dyno project

## RE: Braked dyno project

On here, P = (inertia x N2^2/2 - inertia x N1^2/2) / dt

What is ^?

Thank you very much tbuelna for the input, where can I see some information on this DC dyno? I already are working on edd current basis but I can test on future projects.

## RE: Braked dyno project

http://www.dynesystems.com/what-is-a-dynamometer.h...

## RE: Braked dyno project

^2 means square the value.

The second formula is using SI units. kgm^2 and rad/sec

It would likely help to understand the second formula. Look up rotational kinetic energy and power (physics) on Wikipedia. The rotational kinetic energy is in J or Watt-seconds. The formula takes the change in rotational kinetic energy (dJ) and divides by the time (dt) taken to effect the change to get the power (W) required for that change.

## RE: Braked dyno project

If brake torque is being measured from stator reaction, the inertia of ALL rotating and reciprocating components must be considered. The total inertia can be measured by comparing torque at a given rpm using two different acceleration rates (one of which could be zero or negative) and working backwards.

Engineering is the art of creating things you need, from things you can get.

## RE: Braked dyno project

Mechanicadesingns, I`m using Labview software.

Gruntguru, can you give a aproach of how you will make the calculation? the power is normally measured at the flywheel so internal inertia should not be in to the maths.

Any recomendation of the best way to measure the mechanical looses?

## RE: Braked dyno project

LionelHutz provided a formula above for calculating the difference.

je suis charlie

## RE: Braked dyno project