Fire Pumps - Benefits of 1770 RPM vs. 3560 RPM?

3/6/2020

A question for the pump experts on the forum; the line of horizontal split-case fire pumps I'm familiar with generally come as 1770 RPM or 3560 RPM.

What is the benefit to using one versus the other? Do contractors generally have a preference? Is cost, sounds, wear-and-tear impacted by the RPM selection? Thanks in advance.

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3 Comments

Dan Wilder

3/6/2020 07:48:05 am

From a high level guess...

A lower RPM motor (assuming pressure and flow are similar) would take more torque to reach the same level of output (less turns, more resistance) and would then take a larger motor to operate. The higher RPM would allow for a smaller motor due to the lesser required torque (more turns, less resistance).

There may be a trade off for higher pressure lower/flow vs lower pressure/higher flow applications where the RPM vs. BHP is better suited and there would also be a reliability factor to take into account for (this is more down the road and based on proper maintenance).

Koray Uluç

3/8/2020 04:29:19 am

Another benefit is that, generally low RPM pumps' NPSHr is less than high RPM pumps. Which is important if you may experiance high pressure drops on your suction line.

Jon Dimanlig

3/11/2020 02:40:13 am

low rpm is preferred if less noise due to vibration is required

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