Running a pump without a gearbox
Running a pump without a gearbox
(OP)
Hi,
I have a VFD controlled 55 kW motor running a centrifugal pump through a gearbox. The motor runs at 50Hz with the current setup. Not a vary variable duty, almost fixed speed with occasional slight variation (about 5Hz). Someone has suggested removing the gearbox (for a new stream, same arrangement) and running the motor at about 30Hz instead for the same duty.
As much as I would like to remove the gearbox, this sounds a bit too easy to me. Although it is the same hydraulic power required (about 40 kW), the motor duty is quite different. Without the gearbox the motor needs to produce more torque at a slower speed. Can this kind of thing be accommodated by a standard motor and VFD combination?
Thanks
I have a VFD controlled 55 kW motor running a centrifugal pump through a gearbox. The motor runs at 50Hz with the current setup. Not a vary variable duty, almost fixed speed with occasional slight variation (about 5Hz). Someone has suggested removing the gearbox (for a new stream, same arrangement) and running the motor at about 30Hz instead for the same duty.
As much as I would like to remove the gearbox, this sounds a bit too easy to me. Although it is the same hydraulic power required (about 40 kW), the motor duty is quite different. Without the gearbox the motor needs to produce more torque at a slower speed. Can this kind of thing be accommodated by a standard motor and VFD combination?
Thanks





RE: Running a pump without a gearbox
RE: Running a pump without a gearbox
So if you need 40kW from the motor AT THE SPEED IT IS RUNNING AT NOW through the gear box, then you likely have a load that requires the same torque as an 67kW direct drive motor at the pump at that speed. The gearbox is increasing torque at the expense of speed, but that VFD will NOT do that, you would have the SAME torque at 30Hz as you do at 50Hz. You will end up with insufficient torque at that speed in my opinion.
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RE: Running a pump without a gearbox
RE: Running a pump without a gearbox
RE: Running a pump without a gearbox