How much end float should i see

[jboy]

During a factory test of a generator it was noticed a considerable amount of end float on the generator shaft (drive end). This was probably due to the fact that the generator was being diven as a motor (uncoupled) for test purpose and it was finding its Magnetic Center.
Eventually a spacer coupling will be fitted between the generator and a gearbox which will then be driven by a Gas Turbine.
The question I have is, what ensures the generator will run on its magnetic center when strung together with the gearbox and turbine? Is it the predetermined length of the coupling spacer, and should the end float on the generator shaft be the same as that on the gearbox shaft? Also should I expect to see any end float when all coupled together and is it the thrust pads on either shaft that control this?
Thankyou.

 

[MecArt]

jboy,
I've never encountered with a similar situation that you have so it is not very clear to me but I think that you should consider the dynamics of the system in which you'd like to know the end float.Every component has its own flexibility and dynamic aspects so the end float amount of the system is dependent on the individual system component end floats under the operational loads. This is a typical dynamical stress and movement analysis.Good luck..