Pool Company Telling me to connect Motor to 240 Volts for Longevity

Mode16

New member
Sep 3, 2020
3
Canada
I have an in-ground, salt swimming pool. The entire setup is outdoor in a city that snows a lot (motor, salt panel, heater, filter). My motor (Hayward Super Pump) has lasted 7 years up until a few weeks ago. The pool company replaced the capacitor which lasted 3 weeks. When I brought the motor back for repair, the technician told me that the motor was completely burnt. They told me that usually pumps last 10-15 years, and the reason mine didn't was because it was running on 120 Volts.

I am not an electrician, but the concept seemed strange to me. I thought that we always used 120 Volts in North America and 240 Volts in Europe? Is it even possible to install a 240 Volt outlet for residential use?

I am wondering if this sounds legitimate and if you guys also have your motors connected to 240 Volts.

Thanks in advance
 

Desert Dog

Well-known member
Apr 4, 2020
266
Alpine, Ca
Mine is wired 240 off a breaker in the load center. No plug used. Not sure if the pump last longer, I've been told and not verified, they are more efficient wired 240. If you have an electric dryer outlet in your house, then you have a 240 outlet. If you have central A/C, then you have a 240 circuit. I also have a 240 in my garage to run a welder. Not uncommon at all.
 
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sean.a.hyde

Well-known member
Jun 5, 2018
131
Pittsburgh, PA
I am not an electrician, but the concept seemed strange to me. I thought that we always used 120 Volts in North America and 240 Volts in Europe? Is it even possible to install a 240 Volt outlet for residential use?
The power coming into your house is 240V "split-phase". So there are two "hot" legs that are 180 degrees offset in phase. If you measure the voltage between them, you get 240V. If you measure the voltage between either of them and Ground, you get 120V. (There are other voltages in the US that are common in commercial such as 230V 3-phase, 480V 3-phase, etc).
Several household appliances almost always run off of both phases (240V) such as Air Conditioning, Electric Dryers and Electric Ovens.

I have an in-ground, salt swimming pool. The entire setup is outdoor in a city that snows a lot (motor, salt panel, heater, filter). My motor (Hayward Super Pump) has lasted 7 years up until a few weeks ago. The pool company replaced the capacitor which lasted 3 weeks. When I brought the motor back for repair, the technician told me that the motor was completely burnt. They told me that usually pumps last 10-15 years, and the reason mine didn't was because it was running on 120 Volts.
This sounds like someone who doesn't know what they are talking about. Yes, running a motor off of 120V means that, for a given output power, the current is higher, and therefore the windings will be hotter. That said, the motor is rated to run at a certain current, and shouldn't "burn up" at that current, regardless of how long you run it. If the windings are actually "burnt", then a short, open, or other issue developed.
The one potential exception would be a VSP motor where the current is regulated by FETs or IGBTs and these have an operational life that is dependent on their temperature... though again, I would hope these components were sized for their rated current.

Full disclaimer: I am not an electrician.... but I have BS and MS degrees in Electrical Engineering...
 
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mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,760
Pleasanton, CA
An induction motor running on 120v vs 240v has exactly the same current and power running through the windings. There are two separate windings (one per pole) in a dual voltage single speed motor. The two windings are fed in parallel for 120v and in series for 240v so the voltage drop across each of the poles is 120v and the current is exactly the same so the power used and the power dissipated is also exactly the same. The only part of the motor that carries higher current is the terminal block and maybe the thermal limiter but they are dimensioned for the higher current.
 

JamesW

TFP Expert
Mar 2, 2011
21,058
They told me that usually pumps last 10-15 years, and the reason mine didn't was because it was running on 120 Volts.
Motor quality has dropped off significantly over time (in my opinion). It might have been possible to get 10 to 15 years previously under good conditions. However, you are lucky to get 5 to 7 years with the current motors.

One of the main causes of motor failure is a seal leak that gets the bearings wet and causes corrosion. Check frequently for a seal leak and fix immediately if a leak occurs.

As far as 120 vs. 240, I would always recommend 240 volts if you’re running new power. If the power is already installed at 120, it’s probably not worth running new wire to change to 240.

If the power supply wires are undersized for the pump, you can get excessive voltage drop, which can cause problems. You can check the voltage going to the pump under load if you have any reason to question the power supply.

Make sure to keep the motor clear of debris so that the fan can circulate air over the motor and keep it cool. There is a fan attached to the shaft in the motor that pulls in air from the front bottom vents and pushes it out of the back bottom vents.
 
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sktn77a

Gold Supporter
May 16, 2010
1,903
Chapel Hill, NC
An induction motor running on 120v vs 240v has exactly the same current and power running through the windings. There are two separate windings (one per pole) in a dual voltage single speed motor. The two windings are fed in parallel for 120v and in series for 240v so the voltage drop across each of the poles is 120v and the current is exactly the same so the power used and the power dissipated is also exactly the same. The only part of the motor that carries higher current is the terminal block and maybe the thermal limiter but they are dimensioned for the higher current.
This makes sense but every pump label I've ever seen shows twice the current at 120v compared to 240v:

pump label.jpg
 

JamesW

TFP Expert
Mar 2, 2011
21,058
The voltage and current across each winding is 115 volts and 5.4 amps.

For 230 volts, the windings are in series.

For 115 volts, the windings are in parallel.

For windings in series, the voltage adds together. For windings in parallel, the current adds together.

So, the ratings on the label are what you see at the supply wires, not what each winding gets.
 
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Dirk

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TFP Guide
Nov 12, 2017
7,092
Central California
This makes sense but every pump label I've ever seen shows twice the current at 120v compared to 240v:

View attachment 160954
I'll take a stab. I think you're equating amps to the amount of work getting done, or heat generated, when you should be thinking watts for that.

A watt is the unit of power, not an amp. Watts = work performed (horsepower).

And watts = volts x amps. Using your label:

115 volts x 10.8 amps = 1242 watts.
230 volts x 5.4 amps = 1242 watts. Same-same.

So yes, wired for 115 volts, the pump will draw more amps than if wired for 230, twice as much, but will not use more power (watts). The same amount of work gets done, the same amount of water gets moved. The cost of the electricity is the same. The amount of heat generated is the same. The primary reason pumps are made to use either voltage is for convenience of wiring, nothing to do with performance or wear'n'tear.

Now, if someone can explain to me why we see voltage ratings of 110/220 and 115/230 and 120/240, that'd solve a mystery for me!
 
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JamesW

TFP Expert
Mar 2, 2011
21,058
Now, if someone can explain to me why we see voltage ratings of 110/220 and 115/230 and 120/240, that'd solve a mystery for me!
It's basically impossible for the power company to provide an exact voltage. So, they do their best to keep the voltage in a narrow range.
The range is about 220 to 240. They have to call it something. Some people use the lower limit for the name. Some people use the upper limit and some people use the middle.
The proper name would be a description of the bell curve that represents the the range of typical voltages, but that's impractical.
 
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Dirk

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Nov 12, 2017
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Central California
Right, of course. I suppose since the load is in constant flux (as thousands of people turn things on and off), so is the voltage. I'm now picturing a giant regulator of sorts, somewhere in the mix!

So when manufacturers provide spec's for their products, they just pick one of those voltages and they're common enough that everyone "knows what it means," and it is implied that the product will work without issue within some variable range, I guess. Thanks James.
 

Dirk

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TFP Guide
Nov 12, 2017
7,092
Central California
Will a motor run cooler off 240 then 120 or the same? Heard that once and no clue if it’s true
I would think same, because either wiring will use the same amount of watts and produce the same amount of work. Though there could be some subtle real-world difference. If so, it'd have to be negligible.
 
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Mode16

New member
Sep 3, 2020
3
Canada
As an added point, the motor was indeed running very hot this summer. Is that a normal symptom of a "dying" motor or does it seem likely that something was off in the rest of the pool system?