Need help with correct replacement motor

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Johnl

Johnl

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May 3, 2008
88
Montgomery County, PA
I think the bearings are starting to go on my AO Smith motor, so I am thinking about possibly replacing it with a model that is more energy efficient. I'd like to get your thoughts on the models I'm looking at.

Current motor:
AO Smith 1.5 HP, 1.1 SF

Single speed option:
Emerson 1.5 HP, 1.5 SF

Two speed option:
Emerson 1.5/.25 HP, SF 1.47

I'm not sure if it makes a difference but I have a square flange 56Y motor.

Thanks,
 
I was about to start a new thread but I'll bump yours instead and add a bonus Q to it.

I'm also about to replace a pump motor and considering an enercy efficient model.
Currently run a 1.5HP with 1SF AOSmith motor on a Superpump.
EE replacement for this particular motor would be (CT1102) a 1HP, 1.4SF motor.

Q is: according to a coouple of "experts" the eneregy efficient models have less copper and do not last as long as the standard models (3-4 years compared to 5+ on standard).
Can anyone confirm this?
Am I selling myself short thinking that I'll save some $$ on the electric bill, yet end up replacing the EE motor much sooner than a standard one?
-99


PS:
OP-both of your replacement options are much stronger than original (original: 1.5*1.1 versus 1.5*1.5 on replacements).
Are yousure you need to increase the actual HP of your motor/pump?
 
Based on what I have seen in my research, the EE have less copper because they use permanent magnets in the motors.

A standard induction motor has a set of coil(s) that provide the magnetic field for the armature wiring to react with. With permanent magnets no need to use that additional outer coil to generate the magnet field.

Less electricity consumed. Less copper by eliminating those windings.

I am sure others in the know will fill in if I have missed anything.
 
99ways2die said:
I was about to start a new thread but I'll bump yours instead and add a bonus Q to it.

I'm also about to replace a pump motor and considering an enercy efficient model.
Currently run a 1.5HP with 1SF AOSmith motor on a Superpump.
EE replacement for this particular motor would be (CT1102) a 1HP, 1.4SF motor.

Q is: according to a coouple of "experts" the eneregy efficient models have less copper and do not last as long as the standard models (3-4 years compared to 5+ on standard).
Can anyone confirm this?
Am I selling myself short thinking that I'll save some $$ on the electric bill, yet end up replacing the EE motor much sooner than a standard one?
-99

PS:
OP-both of your replacement options are much stronger than original (original: 1.5*1.1 versus 1.5*1.5 on replacements).
Are yousure you need to increase the actual HP of your motor/pump?
Click to expand...


A little more horsepower would be a good thing since my pool cleaner has a tendency to get stuck in the steps and needs enough flow to get out of the corners, but I didn't know if the difference in motors that I was looking at was too much was too much. What do you think?

My motor now is only 4 yrs old and already starting to go, so I would be concerned if the EE motors didn't last as long. This is the first I've heard of the shorter lifespan.
 
You really should calculate the correct HP rating for your particular pool, plumbing, etc.
I forget where, but there is a guide for this. I just wanted you to be aware that you were talking about replacing a motor with 1.65 break horsepower with one which will have 2.25
(big difference IMO, but I'm no expert....especially if you have to take a water-propelled cleaner into your calculations)

My pool has certainly enough power with that 1.5HP motor, and replacing it with a 1.4 won't make much of a difference.
Just installed "poolskim" on Saturday, and that sucker....well, sucks. :)

I am going to order the EE motor on the intertubes today.
I'm fed up with pool stores, and as seldom as I walk into one it seems I need a reminder every how and then why I feel that way.
One of the local stores supposedly had the EE model coming in on Friday. They had a good price on it as well. Figured - why not.
I show up on Sat. morning, provide exact model I'm looking for...."sure, we have it-I'll get one of the guys to bring one in a min."
A couple of mins. later I'm staring at a nice AOSmith box. The guy's about to ring it up but being wise enough to know better I ask that we open the box on the counter just to make sure the numbers match on the motor. 30 secs. later I'm looking at the label which clearly states ST1102, which is the standard model.
So I say "this isn't what I wanted".....he stares at me; says this IS there motor. I say "no, I asked for the EE motor....on the phone 2 days ago, then this morning again, then just a minute ago at teh counter."
The guy goes in the back, and returns with an older gentleman, which proceeds to ask me why I need the EE motor. Thought about the answer for a sec and replied "because it IS energy efficient???"
His answer: "we don't install them don't sell them and don't recommend them to anyone....they have less copper and burn out much faster than everything else. Just get the standard motor so you don;t have to change it every 3 years."
At that point I simply gave up, said "Ok, if you say so," gestured that I won't be buying that motor and walked away.
I tried to give a local shop my business, but once again I was reaffirmed in my previous opinion on pool stores: a bunch of know-it-alls who seldom have the right answer.

Sorry for the rant in your thread, figured it was worth sharing.
I'm buying that EE motor online, and if it truly burns out in 3-4 years I'll buy another one....just to spite them all and feel good about my choice anyway. :p

Good luck with your replacement/etc.
-99


PS:
Can anyone attest to the longevity of the EE motor(s)?
 
Johnl said:
Has anyone else heard of energy efficient motors breaking down faster than standard efficiency motors?
Click to expand...

Not that I am aware of. Energy efficient motors generally have 20% more copper (larger diameter wire) to reduce the resistance in the wire which makes them more energy efficient and more costly. They also have higher tolerances so the stator and rotor gaps are closer together and they will sometimes use better bearings as well to reduce friction loss. So they tend to be heavier than conventional motors and also the startup current tends to be higher. Also, the only pool pump motor that I am aware of that uses a permanent magnet is the motor used in the Intelliflo. Here is a pretty good article on how high efficiency motors are designed.

In addition, using a larger BHP motor with the same impeller is very inefficient. The impeller design imparts a specific load to the motor so the motor must be match to that load. Using a significantly larger motor will only use more energy not deliver any more flow rate. So you are better off using a standard motor with the same BHP than using an energy efficient motor which is 50% larger in BHP. The energy wasted will be quite high and may shorten the life of the motor because the heat will be higher. It is ok to go with a slighter larger BHP but best to keep it within 10% if possible. Also, you never want to go with a lower BHP motor as that will definitely shorten the life of the motor.
 
Thanks for the info and the link-much appreciated (read the whole thing).

Wonder if I'd come out with a black eye if I said to the pool guy at the store that EE motors actually have MORE copper, and not less, when he laid his "wisdom" upon me.
;)

Good thing you brought up the impeller as well, I totally forgot (not changing mine so wasn't thinking about that at all).
-99
 
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