280V motor on 230V circuit

|>> On Apr 26, 6:14 pm, Jamie |>> wrote: |>>

|>>>Deodiaus wrote: |>>>

|>>>>I have a broken pool motor [magnetek y56y] which will cost a bundle to |>>>>fix |>>>>or repair. |>>>>While doing a search on the web, I found the same model (really cheap) |>>>>but |>>>>wired for 280V, instead of the 230 V load that my wiring is supplies. |>>>>Now, I was thinking of buying the cheap 280V model and installing it |>>>>instead. Aside from rotating at a different speed and |>>>>maybe some power inefficiencies, are there any other drawbacks of |>>>>using the 280V model |>>>>instead? |>>>

|>>> are you sure it isn't 208 ? |>>>

|>>>--

|>>

|>> I'd be suspicious that the 280V was a misreading somehow of 230V. |> that sounds more plausible. |>

|>

| | | Misreading of 208V undoubtably, 208 is very common in commercial buildings, | that and 277.

And where you have 277 you almost certainly have 480. But I suppose it is possible to have 277 alone (is better to use than 120 for lots of fluorescent lighting) or maybe even a 554/277 Edison style single phase split system, where three phase distribution is not available and the higher voltage is desirable for large areas of commercial lighting.

Yes. - but where is it grounded. Formerly it was grounded only at the star (centre) point of the local transformer, but more recently is it being grounded (again) at the domestic intake point.

Yes, although we have 3 types of supply arrangement for earthing used on public supplies. (Note that on 240V, there's often far more distance between the consumer and the transformer than you'll find in the US on 120V supplies.)

TN-S: Neutral is grounded only at the transformer, but a separate earth conductor is carried in the supply network and brought into the home from that same grounding point.

TN-C-S (also known as Protective Multiple Earthing): A single PEN (Protective Earth and Neutral) conductor from the transformer serves as both neutral and ground connection in the supply network. The PEN conductor must also be earthed regularly throughout the supply network, and it requires very high integrity connections to ensure the risk of it breaking is very low (this is a legal requirement). Once the supply reaches the consumer, the PEN conductor is split into separate neutral and earth conductors in the installation.

TT: The supplier grounds the neutral as for TN-S, but doesn't provide the consumer with any earthing connection. The consumer needs to make their own ground connection for earthing (and shouldn't cross-connect this to the neutral). TT is only found on old rural overhead supply networks, and they are upgraded to TN-C-S when due for refurbishment.

Even if the supplier does provide an earth connection (TN-S or TN-C-S), the installation can choose to ignore it and be wired as a TT system. This is sometimes done for submains to outbuildings and outdoor electrics, even when the main installation is TN-S or TN-C-S.

These earthing system arrangements are covered in the uk.d-i-y FAQ:

One common neutral that is grounded back at the nearest transformer substation, and three phases, fed singly to homes in a reasonably 'balanced' way (loading-wise). So one side of the street may be fed from one phase, and the other side of the street from a different phase, then further up the street, some more houses connected to the remaining phase and so on. Each house also has a protective ground connection. Generally, no 'pole pigs' except in rural areas. For the most part, each collection of several hundred houses, are connected underground to a small building containing 3 phase transformers. I think that the input to these stations is around 11kV, also underground. The 'hot' side of the supply is usually known as "live" in the UK, but is sometimes also known as "phase".

I'm not an electrical engineer, but that's pretty much the basis of the UK domestic distribution system. Commercial premises usually have a full three phase plus neutral connection to the network.

Arfa

Well, I understood what he meant, but maybe I took it the wrong way. When he said middle conudctor I was thinking the center lug on the transformer which is grounded and used as the neutral.

Mike

In the USA they ground the Neutral at the transformer and do not run a seperate ground conductor to the house. There is however a ground rod driven which is tied to the neutral at the entrance to the house. ]

I tried first by replacing the capacitor. I could not pry off the pump because it was rusted shut and bolted on well. The repair guy said it was a break in the winding. He is rewinding it for $170. I was thinking of doing it myself but I was told that rewinding it manually is tough.

BTW, I cannot refind the "for sale" motor on the web anymore.

|> |>> There are two different flavors of 220/230/240 volts. Some places |> |>> have a |> |>> simple system with one wire hot and one wire grounded. Other |> |>> places have |> |>> a split system where the voltage is split in half to get |> |>> 110/115/120 volts |> |>> relative to ground, by adding a additional "middle" conductor that |> |>> is the |> |>> grounded one. |> |>

|> |> Sonny, you need to LEARN the difference between Ground and |> |> Neutral...... |> |> before you spout any further BS....... |> | |> | What he wrote looks reasonable to me in terms of ground and neutral. |> | Neutral is the grounded conductor where I live. He does not say to |> | use a ground as a neutral, if that's what you're getting at. I can |> | only guess that that may be what you're getting at, you haven't really |> | said. |>

|> He might be one of those "knows just enough to be really dangerous" people |> on the net. I didn't even mention "neutral". My intent was to explain it |> in a simpler way for someone to just understand the basic difference. The |> term "middle" was to convey a little more information than "neutral" would | | | Well, I understood what he meant, but maybe I took it the wrong way. When he | said middle conudctor I was thinking the center lug on the transformer which | is grounded and used as the neutral.

That is what I meant when I said middle conductor. I intentionally avoided calling it neutral for the person I was responding to. I did quote it to make it clear (but this apparently was not clear enough for at least one person) for others that I was using some other term.

In alt.engineering.electrical Andrew Gabriel wrote:

| Yes, although we have 3 types of supply arrangement for earthing | used on public supplies. (Note that on 240V, there's often far | more distance between the consumer and the transformer than | you'll find in the US on 120V supplies.)

Our supplies to homes are also 240V. We just ground it in a different way through the use of a center tap and an additional wire, which gets the neutral designation. For an equivalent _balanced_ load in the US, we should see no more voltage drop than in the UK. And that voltage drop will be effectively halved between one of the hots and the neutral.

| TN-S: | Neutral is grounded only at the transformer, but a separate | earth conductor is carried in the supply network and brought | into the home from that same grounding point. | | TN-C-S (also known as Protective Multiple Earthing): | A single PEN (Protective Earth and Neutral) conductor from | the transformer serves as both neutral and ground connection | in the supply network. The PEN conductor must also be earthed | regularly throughout the supply network, and it requires very | high integrity connections to ensure the risk of it breaking | is very low (this is a legal requirement). Once the supply | reaches the consumer, the PEN conductor is split into separate | neutral and earth conductors in the installation. | | TT: | The supplier grounds the neutral as for TN-S, but doesn't | provide the consumer with any earthing connection. The | consumer needs to make their own ground connection for earthing | (and shouldn't cross-connect this to the neutral). | TT is only found on old rural overhead supply networks, and | they are upgraded to TN-C-S when due for refurbishment. | | Even if the supplier does provide an earth connection (TN-S | or TN-C-S), the installation can choose to ignore it and be | wired as a TT system. This is sometimes done for submains | to outbuildings and outdoor electrics, even when the main | installation is TN-S or TN-C-S. | | These earthing system arrangements are covered in the uk.d-i-y | FAQ:

I'm curious about this: is it legal in the UK for a home to feed their supply into their own transformer and ground the secondary at that point as a new system?

If you are in North America, and have 120 VAC to the outlets, what you call 220 or 230 VAC in your home is actually 208 VAC, unless you installed some kind of transformer to compensate.

I somehow think that the vendor of the motor made an error. Having 280 VAC sounds to me very unconventional, unless this was some kind of special installation.

I would buy the motor. If in the even that it needed a higher voltage because it lacks torque for your application, then there is the possibility of needed an transformer. This would be expensive.

Some motors have a cover plate inside with strappings, to allow changing its operating voltage, RPM, and direction of rotation.

If you were to run a synchronous motor on a lower voltage, it will have lower torque rather than lower RPM, unless the supply voltage was reduced to below the motor's stable operating threshold. Synchronous motors are dependent on the AC frequency (Hz) for their RPM.

No, that's not true. It's 240V, the transformer has a grounded center tap so

It's clearly a typo and should be 208V.

If it's not a silly question, with the motor in question being offered "on the web, really cheap", then if it's e-bay, why not use the 'ask the seller a question' option, or if it's a reseller, use his on-site 'contact us' facility ? Then there would be no debate about typos and exotic voltage issues ... :-)

Arfa

This is standard with "pool stuff" around water.

He is right, it is.

Here's the first lesson in "shopping like a woman": Ya snooze, Ya loose! You see that "good price" you MUST buy it right then and there. If you futz around trying to make up your mind, it'll always be too late! Later it will be gone. [Hey, you think there's nobody else out there who can spot a bargain like you?]

| If you are in North America, and have 120 VAC to the outlets, what you | call 220 or 230 VAC in your home is actually 208 VAC, unless you | installed some kind of transformer to compensate.

That's only true if the source transformer is a three phase WYE/star type. If you have center tapped delta three phase, or single phase Edison split, then you have genuine 240 volts (although with that delta you may also have a third wire that is 208 volts relative to ground/neutral).

| I somehow think that the vendor of the motor made an error. Having 280 | VAC sounds to me very unconventional, unless this was some kind of | special installation.

It may be a reference to working on 277 volts, which is an available voltage in some large commercial/industrial locations.

yeah, where do you find 280 volts? it's either 208 or 230.

? "Deodiaus" ?????? ??? ?????? news: snipped-for-privacy@x41g2000hsb.googlegroups.com...

Yes-it could be toast in a couple of seconds. While motors with brushes, like the ones used in short duty appliances, like drills and blenters, will rotate slower in lower voltages, without problems, Asynchronous motors (brushless) will really smoke to death if used in voltages significantly lower than nominal. Can't you find a generic pool motor, if you know the horsepower, voltage (3 phase? line to line) and intake and outlet gauge? and maybe rpm?

HTH,

Nope. LV (low voltage)230-V in Europe is just sufficient for 1 km distance. MV (medium voltage) 20 kV for 60 km. HV (high voltage) 150 kV for 220 km. EHV 400kV for 500 km with stability issues. 110 volt is so low you need a transformer outside each building....

Learn the system before you criticize it.

It's not 110V, it's 240V, we simply split it with a grounded center tap which gives 120V between each side and neutral, or 240V between the sides.. There's no transformer per house, except rural applications. Generally 5-10 houses are on each transformer, sometimes more. The problem with long runs is that the voltage fluctuates substantially with large loads such as central air conditioning. Standard North American residential service is 200 Amps 240V, I gather this is quite a bit larger than typical European domestic stuff, so stretching it over 1km distance would require prohibitively large cables or suffer from wide voltage swings. Makes more sense to run 7200V down the street and locate a smallish transformer near every half dozen houses.

Most countries are 230 Volts (50 Hz) with some exceptions, such as North America, parts of South America, Japan, and a few others. Nearly all of Europe is standardized on 230 Volts 50 Hz, although outlet/plug shapes still vary from country to country.