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Topics: Is it mandatory to use VFD based controllers with Electric Motor driven Fire Pumps? on Variable frequency drive
#1
Start by
Eby Daniel
01-17-2014 11:45 AM

Is it mandatory to use VFD based controllers with Electric Motor driven Fire Pumps?

Dear All, Is it mandatory to use VFD based controllers with Electric Motor driven Fire Pumps? Is NFPA-20 recommended the same or not? We proposed Wye-Delta type controllers for one of the project here in UAE but consultant asking for VFD based controllers type. Also, anyone could explain what are the Merits and Demerits of using the VFD based controllers?
Thanks in advance for your Advice & supports.
01-17-2014 01:58 PM
Top #2
James S. Nasby
01-17-2014 01:58 PM
It is not mandatory to use any particular type of controller. It is only requited that they be "Listed".

Variable speed controllers can, and do, solve problems relating to excessive pressure. They typically save a lot of money compared to other solutions. The down side is that they cost more than fixed speed controllers. This is to be expected since they are a combination of both variable speed controller AND fixed speed controller (in the Bypass mode).

Here is a presentation I did on the topic:

http://www.slideshare.net/JamesSNasby/fire-pump-system-pressure-control

Note that I'm the co-inventor of this type of controller.
01-17-2014 04:44 PM
Top #3
Darren Mansur
01-17-2014 04:44 PM
I sell both fire and municipal pumps and controls, including VFD's. Lots of consultants in municipal spec VFD's because they are relatively inexpensive and they can make up for a lot of sizing mistakes in HVAC/municipal applications. The run-cycle of fire pumps vs. these other pumps also makes the HVAC/muni VFD much more cost effective as it controls the energy consumption of pumps that run continuously. In fire VFD's are much more expensive, but are a good fit in the right application. As above, they help solve issues with excessive pressure. I have never had a project in which their use was mandatory, but a couple of projects where it was the best fit.
01-17-2014 07:21 PM
Top #4
Darrell Underwood
01-17-2014 07:21 PM
I agree with both comments but would not use unless I had a good reason from an eneering stand point.

Darrell
01-17-2014 10:16 PM
Top #5
Muhammad Asif Sohail
01-17-2014 10:16 PM
No it is Not mandatory, but good to use to adjust pressure in Piping.
01-18-2014 12:33 AM
Top #6
James S. Nasby
01-18-2014 12:33 AM
This is a little "off topic"; but, this presentation discusses various starting means for fixed speed fire pump motors:

http://www.slideshare.net/JamesSNasby/fire-pump-motor-starting-presentation

Note that this also applies to the starting method for variable speed fire pump controllers in their "Bypass" mode.
01-18-2014 03:12 AM
Top #7
Francisco Carvajal
01-18-2014 03:12 AM
Hi Eby,
I suppose that when you propose obsolete wye-delta type controller, the consultant proposes the VFD type controller.
Is wye-delta type required due to the potential of the motor???
Is VFD really required due to the variation of pressure???
Carvajal
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