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Balancing of High Speed Turbine Rotors.

Balancing of High Speed Turbine Rotors.

Balancing of High Speed Turbine Rotors.

(OP)
Balancing of high speed turbine rotors details.
Speed: 4596 RPM
Type of balancing (grade): dynamic as per API-617
Biggest impeller diameter: 1346 mm
Rotor weight: 7286.6 Kg.
i want to know which  type of drive system to be used for balancing of such type of rotors.
Unversal Joint drive or Belt drive system.
unversal joint drive means:-drive by coupled drive & belt drive means rotor driven by belt whilw balancing.
 

RE: Balancing of High Speed Turbine Rotors.

I recall API-617 may include a spec for balancing at operating speed.  End drive is about the only way to drive a rotor that needs serious horsepower.

An end drive balance procedure should include indexing the u-joint/drive shaft to test for the driveshaft's influence. There will be some.

RE: Balancing of High Speed Turbine Rotors.

For our high speed turbine rotors, the turbine repair shops we contract with have a universal joint drive system.

RE: Balancing of High Speed Turbine Rotors.

I have seen plenty of turbine and generator rotor balance operations and I can't ever recall seeing a belt driven set up.  Does your description of belt drive mean that the belt is slung over the turbine rotor itself or is it via a pulley on the end of the rotor.  The wording makes me think the former and that would mean that the belt tension would have to be accounted for.

rmw

RE: Balancing of High Speed Turbine Rotors.

We have one balancer that can handle up to an approximately 3000 lb shaft that is belt driven. The shaft sits in 2 roller bearings and the belt is wrapped in a convenient space. The belt is driven by a ten HP DC motor. If I recall the belt is set with idler pulleys and drives the rotor straight down.  The whole system is on a floating bearing assembly.

Not ours but similar. Look at the biggest one it can also be belt driven.

http://www.universal-balancing.com/horizontal-balancing-machine.cfm
 

RE: Balancing of High Speed Turbine Rotors.

Hard and soft bearing balance machines can use belt drive. the trick is to orient the belt tension perpendicular to the measurement direction. Otherwise eccentricity etc can create a 1X signal that the eager-to-please balance machine interprets as unbalance.

Comparing Calcs for HP that can be transmitted with available drive diameters/rpm Vs windage HP may eliminate belt drive real quick.  Paper and tape or clamshell housings may reduce windage some, but there's a limit.

RE: Balancing of High Speed Turbine Rotors.

Assuming the turbine could be belt driven it would need to drive onto a dia of at least 2 feet to get a reasonable torque to accelerate the unit - this gives a belt speed of   500 ft per min - - possibly a bit high !! and how about slowing it down ?? However,the rotor would also need axial restraint which would be quite substantial. Go for end drive.
Regards CM

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