I'm willing to learn. Could it be the HP developed by a "bare" engine (e.g., one that is not yet installed or connected to the power equipment) at its "rated speed", aka "gross horsepower" ?
Bare-shaft horse power is, in the case of a pump unit - the power input to the pump shaft (which already includes the pump losses and ineficiencies),it does not include any losses for the coupling or the drive unit.
To put it another way: if the pump at the point of best efficieny requires 100kW and the loss through the coupling is 0.5kW and the inefficiencies of the electric motor driver are 3.5kW,then the energy input to operate the pump at BEP would be 104kW, calculated from voltage, amps,power factor, efficiency etc.
This becomes the input power to the pump unit as compared to the input power at the pump shaft, ie., 100/104 Kw .
If it was a engine driven unit, you would need to measure the fuel input and convert that to total energy input - this is not so easy to do but can be calculated by the engine manufacturer.
Bob
I think the problem with a thread just for the "definition of pump terms" will be controlling what is included.
Having watched this forum for awhile - here is a huge amount of mis-information passed round in the guise of "expert" advice. I would be concerned that any mis-information that is likely to end up there and not removed immediately might be believed by those not able to sort out the right from wrong.
Maybe we would better serve those looking for information to direct them to recognised site which have controlled and accurate information.
Some of the comments you made may be disturbing. Why can't you oppose or redflag misinformed posts? Further, I never saw anybody declaring themselves as experts here, though some of the guys(including you) here make excellent contribution in these forums. I firmly opine redirecting posts to another recognised site is in the least interest of these forums. It is unfortunate to have such type of comments. We are here to help out each other.
As far as I know, the definition you gave is for BHP(Brake Horse Power as generally known) and I didn't see any reference which clearly defined what a Bare Shaft Horsepower is. This is not to prove that I know about pumps well but to just show that things are taken for granted in the absence of generalized data.
Quark
The problem is like many others I am not an expert, therefore any mis-information posted to a thread dedicated as giving "definite" information may not be opposed or red flagged in time, if at all, this then becomes "a truth" (it must be true, I saw it in Eng-Tips Forum) this does not benefit the forum or people using it.
Maybe my reference to "expert advice" was a bit of an over-kill.
I however agree with you completely, there is great information and suggestions made by many competent members of the forum, which hopefully is always taken as advice or help or another opinion and acted on accordingly.
Bare shaft horsepower is a reference term only and implies exactly what it says, - power input at the pump shaft - bare of anything else ie, couplings, gearboxes, hold-backs etc.
Thanks for your reply and I guess you were in a pretty bad mood the other day. I am extremely sorry if my previous post sounds any offence but it resulted from the attachment I have with these forums and I feel the sentiment is likewise at your end too.
