Getting rid of "Service Factor" for motors.

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The link that you provide says that the replacement motor is a 1 hp motor with a 1.65 sf and that it is the correct replacement motor for the 1.5 hp up rated WhisperFlo.

I think that the motors are the exact same motor for the full rated pump and the up rated pump. So, I don't think that it makes any difference which one you use.
 
Wow folks! 3 pages on this, really? I guess that fact alone speaks to the confusion with sf. Here's what I think is most important in the real world. Most pump motors don't fail because of sf confusion... it's the bearings that fail because of a seal leak in the pump. This allows water intrusion to the motor bearing. Then when you try to replace the bearing you find the long thin bolts that have to be removed are frozen and break when removal is attempted. For most people this now means replace motor. The bolts freeze because it's a steel bolt installed in a magnesium or aluminum casting. Dissimilar metal corrosion begins almost at day one since there is no corrosion mitigation. So I remove the bolts one-at-a-time (power off of course) when the pumps are new and lube with anti-seize. This way the pump motor is easily disassembled and bearing replaced. $20 bearing instead of $200+ motor... and best of all no need to deal with sf since you use the old motor!

I hope this helps.

Chris
 
While the title and the description state that the pump is 1 HP with a SF of 1.65, the label on the pump states that the pump is 1.65 HP with a SF of 1.00 (https://cdn3.volusion.com/dcxtx.dmgag/v/vspfiles/photos/MBPA450V1-8.jpg?1423031613). So it's important to look at the label and in this case the recommended replacement again is one in which the Service Factor is either the same or lower than the original motor. This is something that I can wrap my head around as it's consistent with the industry experts.


JamesW said:
The link that you provide says that the replacement motor is a 1 hp motor with a 1.65 sf and that it is the correct replacement motor for the 1.5 hp up rated WhisperFlo.

I think that the motors are the exact same motor for the full rated pump and the up rated pump. So, I don't think that it makes any difference which one you use.
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I think that's a great idea Chris, and although it hasn't happened to me yet, I will do that when I install the replacement motor. I have gotten into a habit of replacing the seals once a year (cheap insurance) given that our desert climate seems to accelerate wear & tear on things out here including pool motors in particular. Our ambient temperatures can approach 50 C (over 120 F) in the summer and I've seen the paint/label bubble off the motor housing on the motors that last over 5 years. It also seems that the older motors (those over 10 years) generally last much longer than the newer motors. I did find a local shop that rebuilds motors so that is also an option.

setsailsoon said:
Wow folks! 3 pages on this, really? I guess that fact alone speaks to the confusion with sf. Here's what I think is most important in the real world. Most pump motors don't fail because of sf confusion... it's the bearings that fail because of a seal leak in the pump. This allows water intrusion to the motor bearing. Then when you try to replace the bearing you find the long thin bolts that have to be removed are frozen and break when removal is attempted. For most people this now means replace motor. The bolts freeze because it's a steel bolt installed in a magnesium or aluminum casting. Dissimilar metal corrosion begins almost at day one since there is no corrosion mitigation. So I remove the bolts one-at-a-time (power off of course) when the pumps are new and lube with anti-seize. This way the pump motor is easily disassembled and bearing replaced. $20 bearing instead of $200+ motor... and best of all no need to deal with sf since you use the old motor!

I hope this helps.

Chris
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The 355010S is listed on the Pentair site as a 1 hp motor in the parts list and the installation manual.

In any case, I think that the motors are the exact same. So, debating which one will perform better is pointless.

Even in the Century link that I provided, the manufacturer specifically says that the motors are the same.

Also, the linked picture is not a 355010S motor.

Century has started to eliminate sf for their motors.

Many Century pool motors now come clearly labeled with the total hp in big print and a 1.0 sf.

I think that they have realized that sf only causes confusion and is not necessary.
 
When an engineer requests a motor from a motor manufacture, they will usually specify the load HP and a service factor (margin) required. The motor manufacture then looks for a motor that has a THP greater than or equal to the design HP x service factor. They then simply print a label for that motor with that design HP and service factor the engineer gave them. But really the THP load is what is used to "size" the motor.

This is no different than in the pool world. Pump manufactures set the same requirements for HP and SF and the motor manufacture then creates the label for those specifications. This is why two motors with the same THP are identical even though the label HP and SF may be different. The pump manufactures have created two pumps with exactly the same specs but different label HP because that is what the market demands. It has nothing to do with the motor life.

So a 1 LHP motor with a 1.65 SF is no less "safe" than a 1.65 LHP motor with a 1.0 SF for a 1.65 THP load. There is no margin either way. Both motors will run at exactly the same temperature assuming the insulation class is the same.

If you really want to utilize SF properly, then you choose the label HP as 1.65 (i.e. the true load) but you also have a margin or SF of some value higher than 1.0. This is how SF is actually used in practice. The SF chosen is based upon the margin required which is determined by the operating environment. If you think you need 20% margin, then choose a SF of 1.2.

However, you won't likely find a pump motor with those specs. But you will find a 1.5 LHP full rated motor with a SF of 1.65. This will provide an effective SF of 1.5 for your pump head.

Again, THP defines how the motor is designed. Label HP and service factor are simply ratings set based upon the motor application and THP.
 
mas985 said:
This has been proven time and time again for over a decade of motor replacements on this web site so it is not really open for debate. I have lost count how many times newbies have come on this site and try to challenge the facts.
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hmmm...the title suggested, otherwise!

Meanwhile, back at the ranch...the pool water is clear. No need to re-invent the wheels!

 
sktn77a said:
So where would this leave 2 speed pumps - operating well below optimal efficiency on the low speed?
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Typical efficiency on low speed drops by about 50% from the high speed value. An impeller spinning at 1/2 speed has 1/8th the power requirement per the affinity equations. But the two speed winding is designed specifically for that lower power requirement so it isn't really "under loaded". The reason the efficiency drops is because smaller gauge wire is used so proportionally there are more I2R losses in the winding.
 

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Instead of WEF, we need a program that will allow someone to input how they will use the pump and the program will show all pumps that are suitable and how much each one will cost for your application.

In my opinion, WEF is meaningless and pointless.

Pool pumps have never been sold or selected by the industry as a whole in a really scientific way.

At best, most people use the most basic Rule-of-Thumb guidelines that rarely make much sense.

At least with variable speed pumps, you can almost not go wrong with a selection.
 
JamesW said:
It took a while, but they finally decided to end the service factor.

Probably mostly due to this thread, in my opinion.
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Didn't they make that decision well before this thread? At the time, we just didn't know about it although perhaps James already did. ;)

History: https://pumps.org/DOE_Rulemaking.aspx
 
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The pump motor THP labeling requirements are part of the DOE regulations that became effective July 19, 2021. The regulations affect only newly manufactured pumps on/after that date. The old stock of pumps can continue to be sold until depleted. The DPPP standard was finished in Jan 2017 but work started on it in 2015.

Pump DOE Regulations - Further Reading

www.troublefreepool.com www.troublefreepool.com
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Again, the full history of this is here: https://pumps.org/DOE_Rulemaking.aspx
 
Note: On February 5, 2018 but before July 19, 2021, any representations made with respect to the energy use or efficiency of dedicated-purpose pool pumps subject to testing pursuant to 10 CFR 431.464(b) must be made in accordance with the results of testing pursuant to this appendix. Any optional representations of energy factor (EF) must be accompanied by a representation of weighted energy factor (WEF).

E.3.3 For dedicated-purpose pool pumps with single-phase AC motors or DC motors, the dedicated-purpose pool pump service factor is equal to 1.0.

Electronic Code of Federal Regulations (eCFR)

Electronic Code of Federal Regulations (eCFR) published by the Government Publishing Office
www.ecfr.gov
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On August 14, 2018, the Department of Energy (DOE) received a petition submitted by a variety of entities (collectively, the Joint Stakeholders or the Petitioners) asking DOE to issue a direct final rule for energy conservation standards for dedicated-purpose pool pump (DPPP) motors. Through this notification, DOE seeks comment on whether to proceed with the proposal, as well as any data or information that could be used in DOE's determination whether to issue a direct final rule.

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As far as I can tell, there are no references to requiring a service factor of 1.0 before 2018.

And the rule did not go into effect until July 2021.

Even now, noncompliant full rated and uprated pumps can still be sold as long as they were made or imported before July 19 2021.

Pool pumps manufactured for use in and imported for use into the U.S. after July 19, 2021, must meet new minimum efficiency standards.

In any case, the manufacturers could have and should have voluntarily stopped making full rated and max rated pumps after they saw my thread outlining why the practice was wrong.


 
mas985 said:
The DPPP standard was finished in Jan 2017 but work started on it in 2015.
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Show a specific reference requiring a service factor of 1.0 on any final rule regulation before February 25 2017.

Even though the general topic of efficiency has been debated for a long time, the rule requiring a service factor of 1.0 is a fairly recent addition.
 
The actual rule adopting the 1.0 service factor was published on August 8 2017 became effective on September 6, 2017

2017-08-07 Energy Conservation Program: Test Procedure for Dedicated-Purpose Pool Pumps; Final rule

Posted by the Energy Efficiency and Renewable Energy Office on Aug 7, 2017

Regarding service factor, DOE appreciates Nidec and APSP's suggestions regarding service factor and agrees that a service factor of 1.0 for all DPPP motors that are subject to the adopted motor horsepower provisions would be more consistent and ensure standardized rating across DPPP models.

It also enables to use of the more direct determination of DPPP nominal horsepower adopted in this final rule. Although Pentair requested more flexibility specifically with regard to service factor, Pentair also requested standardization in horsepower ratings.

As such, in this final rule, in order to better standardize the motor horsepower ratings as recommended by commenters, DOE is adopting a service factor of 1.0 for all dedicated-purpose pool pumps to which the adopted motor horsepower test methods apply.

Regulations.gov

www.regulations.gov www.regulations.gov
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