- #1

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How can I measure, shaft power (watts or HP) of a vertical turbine using dead weight blocks

Turbine diameter - 18 inches

RPM - 450 ( Zero Load)

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- Thread starter dilipbhanu
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- #1

- 20

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How can I measure, shaft power (watts or HP) of a vertical turbine using dead weight blocks

Turbine diameter - 18 inches

RPM - 450 ( Zero Load)

- #2

CWatters

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Fix lever arm to generator casing.

Add rope from lever arm over pulley to dead weight.

Measure rpm an convert to angular velocity

Dead weight * length of lever arm = torque

Power = torque * angular velocity

- #3

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My Turbine is a reaction turbine of 6 inch diameter. It rotates at 2500 RPM generating 15N.m of Torque. The mentioned RPM is measured for shaft rotating (without coupling it to any other machine). Once a Generator is coupled, what will be the final RPM. Will the RPM reduce ? If yes, is there a formula to calculate the final RPM ?

- #4

CWatters

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That statement is inconsistent. If there is no load on the turbine it cannot generate any torque (or power for that matter).My Turbine is a reaction turbine of 6 inch diameter. It rotates at 2500 RPM generating 15N.m of Torque. The mentioned RPM is measured for shaft rotating (without coupling it to any other machine).

What usually/sometimes happens is that as you increase the load the torque increases and the rpm reduces. If you use the right units.. Power = Torque * rpm. So you really need a graph of Torque vs rpm to workout the best operating point (peak power) for the turbine.

Perhaps 2500rpm @ 15N.m is the max power operating point?

Last edited:

- #5

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Motive fluid = Water

Pump Gauge Pressure = 29.86 PSI

Flow rate = Water leaving the turbine = 10LPS @ 19.70 m/s (linear Velocity)

Force = 10*19.697 =

Turbine radius (arm length) = 3 inches ( 0.0762 meters)

Torque = 196.95*0.0762 =

Angular Velocity = 258.49 rad/sec

RPM = 2468

Power = Toque*rad/sec = 15*258.49 =

Is my Torque calculation correct or have i missed something.

- #6

CWatters

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It might be easier to use...

Power = pressure * flow rate

..to calculate the power available.

Which I make 2058 Watts.

If the turbine utput isn't connected to anything then this isn't the output power. It's the power needed to spin the turbine with no load. Eg its the power loss.

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