I have a question regarding fan startup, specifically the jacking oil pump.
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Since the induced draft fan has a large starting inertia, and the owner does not want to use couplings or variable frequency drives, can the jacking oil pump used on the steam turbine be employed for starting it? How much does a set of jacking oil pump system (sliding bearings, oil pump, and thin oil station) cost for a 2000kw, grade 6 motor? I hope an expert can answer this; thank you so much!
The jacking oil pump can be used, taking input and efficiency into consideration.
This jacking oil has nothing to do with starting the machine. In large units, due to the weight of the shafts, there is a path beneath the shafts, and the shafts are jacked up before starting the machine. It has nothing to do with startup. A reasonable and effective method is the coupler
With the use of modern large-scale equipment, the weight of the rotor continues to increase. During low-speed turning, it is not possible to establish a lubricating oil film; therefore, a jacking oil pump is installed in order to reduce the rotational torque of the rotor and the wear on the bearings. Large-scale equipment has high starting inertia and high starting currents. For the belt conveyors at our site, couplings are used to transmit power, while the 3100KW reciprocating compressors employ synchronous motors. I hope this helps you.
Thank you. I would like to ask whether the claim that a top shaft oil pump is used because of excessive starting inertia is valid in itself I remember that the top shaft oil pump is designed to prevent wear on the shaft ends and bearing shells during operation, by lifting them up first so that oil can flow into the gaps
Mm-hmm, thanks for clarifying that. The owner said that hydraulic couplings shouldn’t be used; some manufacturers have proposed using bearing shells, an oil dilution unit, and a jacking oil pump for starting the machine. I think this approach wasn’t designed to overcome the issue of rotational inertia in the first place.
I’ve learned about it; it’s really the first time I’ve seen a top shaft oil pump