Rewiring pool - 110v vs. 220v benefits?

Construction or upgrading of new or existing
swimming pools. Pool building materials and
miscellaneous construction techniques.
flipper-26
Pool Newbie
Pool Newbie
Posts: 1
Joined: Sat 15 Aug, 2009 11:04
My Pool: 16000 gallon roman l pool
Location: Orlando, FL

Rewiring pool - 110v vs. 220v benefits?

Postby flipper-26 » Thu 31 Dec, 2009 23:09

only advantage is that the motor will run cooler via lower amps which will improve effiency of pump.


chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Rewiring pool - 110v vs. 220v benefits?

Postby chem geek » Fri 01 Jan, 2010 02:51

flipper-26 wrote:only advantage is that the motor will run cooler via lower amps which will improve effiency of pump.

This is not true. Read mas985's (Mark's) posts again. The amount of power loss and thus heat (per time) generated through a resistive circuit is I2R where "I" is current (in amps) and "R" is resistance (in ohms; in an AC motor, it's really impedance, Z, that is used, but Ohm's Law, using complex numbers, still applies) and the power is in Watts. There are two windings in a dual-voltage motor where these windings are in parallel for 110V and in series for 220V (there is a manual switch one changes to select which configuration is used). If R is the resistance in each winding, then the resistive heat losses in each configuration are as follows (and yes, I'm ignoring AC impedance and capacitance for simplicity, but it doesn't change the conclusion on resistive losses which generate heat):

PARALLEL (110V applied externally)
Resistance of pump overall (ignoring load) = 1/(1/R+1/R) = 1/(2/R) = R/2
Current applied to pump overall = 110/(R/2) = 220/R
Voltage across each parallel winding = 110 (the voltage is the same across each winding)
Current in each parallel winding = 110/R (the current is split across each winding)
Resistive heat losses = 2*(110/R)2*R = 2*110*110/R = 220*110/R

SERIES (220V applied externally)
Resistance of pump overall (ignoring load) = R+R = 2*R
Current applied to pump overall = 220V/(2*R) = 110/R
Voltage across each series winding = 220/2 = 110 (the voltage drop is the same in each winding)
Current in each series winding = 110/R (all current flows through each winding)
Resistive heat losses = 2*(110/R)2*R = 2*110*110/R = 220*110/R
or equivalently
Voltage across both windings in series taken as a whole = 220
Resistance of both windings taken as a whole = R+R = 2*R
Current through both windings taken as a whole = 220/(2*R) = 110/R
Resistive heat losses = (110/R)2*(2*R) = 2*110*110/R = 220*110/R

The resistive heat losses are the same because the current is the same in each winding in the two cases because the voltage across each winding is the same. In the parallel 110V case, the overall current is split in half to each winding, but the overall current to the pump is twice that as in the series 220V case where the current in each winding is the same as the overall current.

Yet another way to look at this is that the resistance of the parallel circuit is 1/4th that of the series circuit. Since the parallel circuit (110V) has half the overall voltage of the series circuit (220V), the overall power (current times voltage, using RMS and ignoring phase) is the same in both cases because the parallel circuit has twice the current overall (split in half to each winding) but half the voltage of the series circuit.

As mas985 (Mark) noted, there IS a difference in current outside the pump (that is, in the wiring to the pump) so given the same gauge of wire one has less losses outside the pump with 220V, but typically the gauge of wire used is different for 110V vs. 220V. So either the outside losses will be less with 220V or the wiring will be less expensive (narrower gauge) or some intermediate combination, but heat losses (and heat generation) in the pump itself will be the same in each configuration (assuming 220V is applied with a series configuration while 110V is applied with a parallel configuration).

Richard
czechmate
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 401
Joined: Sat 16 May, 2009 09:20
My Pool: 16 x 32 gunite21000 gal., Diamond Brite Blue, Swimquip XL pump, DE36
Location: Texas

Rewiring pool - 110v vs. 220v benefits?

Postby czechmate » Sat 02 Jan, 2010 06:39

chem geek wrote:There are two windings in a dual-voltage motor where these windings are in parallel for 110V and in series for 220V (there is a manual switch one changes to select which configuration is used).

Just for a clarification.
There is no manual switch incorporated in the packer head of any pool pump motor, to change winding configuration.
Not even in the packer head of a three phase 480V or European Delta/Wye.
It is always done by hardwire make-up or a use of jumper configuration in a commercial motors.
chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Rewiring pool - 110v vs. 220v benefits?

Postby chem geek » Sat 02 Jan, 2010 13:15

czechmate wrote:Obviously, the motor connection inside the each motor packerhead will have to be reconnected according to the wiring diagram. For 110V windings are parallel, for 230V they are in series to add resistance for higher voltage. If you forget this part, you will burn the windings in no time!

OK, so it's either a jumper or a reconnection (instead of a physical switch, by which I meant you had to do something physically to change the connection from series to parallel or vice versa -- it doesn't have to be an actual toggle or rotating switch and I should have written "manually reconfigure").

That doesn't change the physics as outlined in the post above. The bottom line is that the series case (220V) has 4 times the overall resistance (impedance) of the parallel case (110V), but has twice the voltage, so the overall current is half; so the parallel case has twice the current entering the motor as the series case. However, the parallel case (110V) has this current split into two (i.e. cut in half) to each winding. So the current going through each winding is the same as that in the series case.

With the same current going through each winding in both parallel and series configurations, please explain how the I2R losses are different.

Also, the series configuration with 220V input is twice the voltage of the parallel configuration with 110V, but has half the current going into the pump so the product of voltage times current (i.e. power) is the same as that of the parallel configuration with 110V. With the same power going into the pump, how is it that the resistive losses are different, given the conservation of energy?
chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Rewiring pool - 110v vs. 220v benefits?

Postby chem geek » Thu 21 Jan, 2010 22:45

I received some further clarification from czechmate. The real-world practical experience has shown that 120V configurations failed more than 220V and failures are mostly electrical, not mechanical. The wire and connections before the split to two windings clearly have twice the current and associated higher heat and this is a particular problem on wire nuts with #12 and small stranded winding wires. He also found that locked rotor currents thru windings were higher with the 120V configuration (though probably not 2x as we showed shouldn't happen).

So, unfortunately, our discussion in this thread diverted to the single focus of theoretical current in a parallel split winding situation and missed the real issue of problems with twice as much current before the parallel winding split (in the motor -- we did talk about such currents outside the motor) and the real-world higher current in the windings (still unexplained unless the two winding configuration has overall lower impedance for some reason drawing more power overall into the motor or perhaps the split is uneven in resistance causing one winding to be higher in current -- this is speculation on my part).
poolpumpguy

Rewiring pool - 110v vs. 220v benefits?

Postby poolpumpguy » Sun 24 Jan, 2010 13:03

only advantage is that the motor will run cooler via lower amps which will improve efficiency of pump. :thumbup:= longer pump and motor life :D hot motors cook the grease off the bearings and stress the windings....a cooler motor is a happy motor :mrgreen: ........ Jay longwood Florida
chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2382
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California

Rewiring pool - 110v vs. 220v benefits?

Postby chem geek » Sun 24 Jan, 2010 14:16

poolpumpguy,

Yes, lower amps is less heat where such current is indeed lower -- that was never the question. The question was WHERE the lower amps were happening. Due to the parallel configuration of the pump at 110V, the current is split in half for each winding so even though the current into the pump is twice as high than with 220V, the current in each winding is essentially the same so the same amount of heat. However, as was pointed out above, the current before the split to each winding is double.

The assertion near the start of this thread was that there was DOUBLE the current in EACH winding in the 110V case and that is simply not true as it would result in QUADRUPLE the current going into the pump (since the current is split into two parallel paths) and that, of course, is not what happens at all. So what was being questioned was the reasoning or explanation, not the experience of what was seen.

Richard
Me...
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 302
Joined: Thu 26 Feb, 2009 11:11

Rewiring pool - 110v vs. 220v benefits?

Postby Me... » Thu 15 Apr, 2010 22:05

LOL

230volts x 5amps = 1,150 watts
115volts x 10amps = 1,150 watts

Guess what, no difference in power consumption.

230 is useful if you wish to use 2-speed motors or bigger motors that can't be run on 115 volts.

The only real difference I see is in Heating. If you have a choice you definitely want 220 volts for your heating so you can go bigger. The 110 circuits seem to take such a beating from being on so much longer to accomplish the same heating task.

The downsides to 230 in a pool shed is you can't know how many time Mr. Homeowner miswires his own jobs and blows stuff up. Gee, I wonder why my light bulbs keep blowing up all the time! etc ...etc..
charby

Rewiring pool - 110v vs. 220v benefits?

Postby charby » Sun 14 Aug, 2011 16:11

Would you replace a 230 v to a 115v?
czechmate
Swimming Pool Superstar
Swimming Pool Superstar
Posts: 401
Joined: Sat 16 May, 2009 09:20
My Pool: 16 x 32 gunite21000 gal., Diamond Brite Blue, Swimquip XL pump, DE36
Location: Texas

Rewiring pool - 110v vs. 220v benefits?

Postby czechmate » Sun 14 Aug, 2011 17:05

There is never a benefit to replace a source for a given horsepower with a lower voltage.
First, either phase may have diferrent existing house load and therefore diferrent voltage drop during the course of a day. You would be hard pressed to find which one to use.
Secondly, your wiring, even if sufficient for lower voltage, will stay cooler at 230V and minimize its own voltage drop. Your packerhead make-up will transfer half the amps inside likely corroded wirenuts.
Your wiring comes in a common pipe to your filter pump, booster pump and the pool light.
20Amp rated #12AWG is allowed to carry only 80% - 16 Amps.
That amperage is further lowered, if there is more current carrying conductors in the same conduit.
Also, you never know how and when your neighbors on the same transformer affect either phase with their loads, so you optimizing with selecting both phases.
(Even though there is no really large single phase loads in the household, beside a coffeemaker and such, lot of homes have their loads pretty unevenly divided to breakers in the panel).

Return to “Building, Construction & Rebuilds”

Who is online at the Pool Help Forum

Users browsing this forum: Majestic [bot] and 12 guests