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49528867 (banned)
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How To Install A 3 Phase A/C Unit On A Camper.

Just have to love the accuracy of the Net.

Air conditioning units for motor homes and campers have been standardized to fit into 14 x 14-inch vent openings on the RV's roof. They accept three-phase alternating current and can be installed by the average mechanic in about a half-hour.

»www.ehow.com/how_5174277 ··· ner.html

Wayne

davidg
Good Bye My Friend
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davidg

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guess since they take 1 hot, 1 neutral, and 1 ground they consider that 3 phase!

Lurch77
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join:2001-11-22
Green Bay, WI

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You need to get with the times. All camp sites have three phase outlets now.

Ken
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Markle, IN

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Three phase A/C for a camper, that would have to be a pretty big compressor.

rex0
join:2002-02-10

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According to the author's bio on the site he studied electrical engineering.....

Lurch77
Premium Member
join:2001-11-22
Green Bay, WI

Lurch77

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said by rex0:

.......engineering.....
That explains everything.
TheMG
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TheMG to 49528867

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eHow, formerly Expert Village

A.K.A.: Idiot Village
The wires--black, green and white--should be cut and spliced to the wires in the roof, then covered with a liberal amount of electrical tape.
Yikes!

neonhomer
Dearborn 5-2750
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join:2004-01-27
Edgewater, FL

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Is that 208-230, or 460?? LOL

cdru
Go Colts
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Fort Wayne, IN

cdru to Ken

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said by Ken:

Three phase A/C for a camper, that would have to be a pretty big compressor.
Does three phase necessarily indicate size? I know that three phase is typically for larger applications, but can you have a small 3-phase motor, such as were you'd typically find a small 120v motor like a box fan?

dosdoxies
Premium Member
join:2004-12-15
Wallingford, PA

1 edit

dosdoxies to rex0

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said by rex0:

According to the author's bio on the site he studied electrical engineering.....
You can always tell an engineer but you just can't tell him much.
TheMG
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Canada
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said by cdru:

Does three phase necessarily indicate size? I know that three phase is typically for larger applications, but can you have a small 3-phase motor, such as were you'd typically find a small 120v motor like a box fan?
The main reason large motors are 3-phase is that such motors are more efficient, more reliable and more practical than a large sized singe-phase motor. It's also much easier to accurately control the speed of a 3-phase motor than single-phase.

The main reason smaller motors are single-phase is because they are typically used in places that do not have access to a 3-phase power supply. Yes, a 3-phase box fan motor would be perfectly doable. It would not be anymore expensive either. But who has access to 3-phase to plug in a box fan?
theboz1419
join:2003-02-12
Puyallup, WA

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I like this tip lol

"Parking the camper next to a second-story window will allow the A/C to be lifted onto the roof from the building."

printscreen
join:2003-11-01
Juana Diaz, PR

printscreen to cdru

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said by cdru:

said by Ken:

Three phase A/C for a camper, that would have to be a pretty big compressor.
Does three phase necessarily indicate size? I know that three phase is typically for larger applications, but can you have a small 3-phase motor, such as were you'd typically find a small 120v motor like a box fan?
Certainly you can have small 3-phase motors. I work at a large manufacturing facility were there are plenty of conveyor belts and similar equipment. I once noticed in one of the lines that a small gearmotor in one of the conveyors was labeled "480 VAC" which in that facility is used only for 3-phase equipment. I asked the engineer in charge if this motor was really 3-phase and he said it was and the main reason was simply reliability and durability. A similar one-phase motor is not as reliable for some reason.

shdesigns
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shdesigns

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said by printscreen:

I asked the engineer in charge if this motor was really 3-phase and he said it was and the main reason was simply reliability and durability. A similar one-phase motor is not as reliable for some reason.
Single phase will likely have a run capacitor, a lower start torque and be less efficient. The capacitors often fail and leak oil.

3-phase motors are much simpler.

Jtmo
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join:2001-05-20
Novato, CA

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Pretty scary.
Though most large rigs have 2 Phase 50A, that is only to feed 2 AC units single phase each, and everything thing else including laundry.

And then there are those who decide to convert their home dryer circuit NEMA-30 plug to plug into their $40000 trailer at home thinking the plug looks the same as TT-30.
Very exciting.....
public
join:2002-01-19
Santa Clara, CA

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said by Ken:

Three phase A/C for a camper, that would have to be a pretty big compressor.
Better units have a bldc motor with a controller, making the supply irrelevant

dandeman
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join:2001-12-05
Chapel Hill, NC

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said by dosdoxies:

said by rex0:

According to the author's bio on the site he studied electrical engineering.....
You can always tell an engineer but you just can't tell him much.
.....studied for one semester before he flunked out?

ITICharlie1
Ass Mode
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join:2003-01-22
Saint Louis, MO

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I also like the fact he mentions using "plenty of electrical tape"...no mention of using wire nuts, and just splicing it into any wiring in the roof...nevermind if it can carry the extra load.
49528867 (banned)
join:2010-04-16
Fort Lauderdale, FL

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said by theboz1419:

I like this tip lol
"Parking the camper next to a second-story window will allow the A/C to be lifted onto the roof from the building."
Down here we call that Southern Engineering which is a process frequently fraught with cost overruns and emergency room visits.

Wayne

macsierra8
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join:2003-11-30
Minden, NV

macsierra8

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The author is an elementary school physics teacher from Blackjack Mountain Ga. This is the kind of folks we have teaching our present and future voters...
49528867 (banned)
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Fort Lauderdale, FL

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said by ITICharlie1:

and just splicing it into any wiring in the roof...nevermind if it can carry the extra load.
Which in a lot of campers may include12 VDC wiring which can look just like the 120 volt wiring.

Wayne

Jack_in_VA
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join:2007-11-26
North, VA

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said by TheMG:

said by cdru:

Does three phase necessarily indicate size? I know that three phase is typically for larger applications, but can you have a small 3-phase motor, such as were you'd typically find a small 120v motor like a box fan?
The main reason large motors are 3-phase is that such motors are more efficient, more reliable and more practical than a large sized singe-phase motor. It's also much easier to accurately control the speed of a 3-phase motor than single-phase.

The main reason smaller motors are single-phase is because they are typically used in places that do not have access to a 3-phase power supply. Yes, a 3-phase box fan motor would be perfectly doable. It would not be anymore expensive either. But who has access to 3-phase to plug in a box fan?
According to the article he referenced a black, white and green wire. That folks is single phase wiring.

I've been in industrial electrical/Instrument/HVAC maintenance for 35 years and this thread is a joke. God I hope no one uses information from these threads as a guide to do electrical work.

The speed of a 3 phase motor is no more or no less easier to control than a single phase motor. Number of poles in the stator determines the base speed of the motor i.e. 2 poles = 3600, 4 poles = 1800 and so on. To have variable speed you need to change the frequency and voltage. 120 volts @ 60 hz = 1800 rpm with a 4 pole motor. 60 volts @ 30 hz = 900 rpm with the same 4 pole motor.

As far as the RV roof ac being 3-phase not likely at all.

rex0
join:2002-02-10

rex0

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said by Jack_in_VA:

...this thread is a joke....
yes, yes it is
beyondo
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join:2007-03-23
Seminole, FL

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fyi: 3 phase is, 3 line (hot) and possibly 1 neutral.
The neutral is not a requirement to be 3 phase.
You generally see 240V, 208V & 480V, 3 wire service in US.
If you have a neutral it would be 120/240V, 120/208V & 277/480V, 4 wire service.
A ground is generally reqired by code, but there are exceptions.
Most homes are wire 120/240V (2 line & 1 neutral) with a ground.
For what it's worth, I cannot think of a reason someone would need a 3 phase A/C unit for normal use...

Lurch77
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join:2001-11-22
Green Bay, WI

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Lurch77 to Jack_in_VA

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said by Jack_in_VA:

I've been in industrial electrical/Instrument/HVAC maintenance for 35 years and this thread is a joke.
It became a joke once people started taking anything here seriously.
61999674 (banned)
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davidg See Profile was making a joke.
TheMG
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said by Jack_in_VA:

The speed of a 3 phase motor is no more or no less easier to control than a single phase motor. Number of poles in the stator determines the base speed of the motor i.e. 2 poles = 3600, 4 poles = 1800 and so on. To have variable speed you need to change the frequency and voltage. 120 volts @ 60 hz = 1800 rpm with a 4 pole motor. 60 volts @ 30 hz = 900 rpm with the same 4 pole motor.
You can't easily use frequency to change speed of a single-phase AC motor. That's why I said it's easier with a 3-phase motor.

If you've got a single-phase motor with a centrifugal switch for the start winding, you can only slow the motor down so much before the switch clicks back in and you fry the start winding.

PSC single phase motors, you need different values of capacitor for the motor to operate efficiently at different frequencies.

Shaded pole motors, forget about it.

3-phase motors are ideal for usage with variable frequency drives.
said by Jack_in_VA:

As far as the RV roof ac being 3-phase not likely at all.
You're taking this thread way too seriously. The very first post was basically laughing at the misinformation found on "eHow". We all know it's a load of crock.

Jack_in_VA
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join:2007-11-26
North, VA

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Single Phase
  

3 Phase
quote:
fyi: 3 phase is, 3 line (hot) and possibly 1 neutral
Most 3 phase is derived from a delta-wye transformer with the secondary being grounded at the connection of all three windings allowing for single phase from any of the three windings to ground or between any two windings. The three phase is used for a three phase device such as a motor. All resistance loads and lighting are single phase that can be derived from a three phase source.

printscreen
join:2003-11-01
Juana Diaz, PR

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said by Jack_in_VA:

As far as the RV roof ac being 3-phase not likely at all.
That was the whole point of the thread. The article in the link referred to 3-phase but when you read the description of the wiring it was plain jane single phase 120 VAC. It is clear that the author has no idea what is 3-phase.

n1zuk
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Malta

n1zuk

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That air condition must be three phase. it has a Low, Med, and High setting.