49528867 (banned) join:2010-04-16 Fort Lauderdale, FL |
49528867 (banned)
Member
2010-Aug-28 5:45 pm
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.htmlWayne |
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davidgGood Bye My Friend MVM join:2002-06-15 00000 |
davidg
MVM
2010-Aug-28 5:49 pm
guess since they take 1 hot, 1 neutral, and 1 ground they consider that 3 phase! |
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Lurch77 Premium Member join:2001-11-22 Green Bay, WI |
to 49528867
You need to get with the times. All camp sites have three phase outlets now. |
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Ken MVM join:2003-06-16 Markle, IN |
to 49528867
Three phase A/C for a camper, that would have to be a pretty big compressor. |
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to 49528867
According to the author's bio on the site he studied electrical engineering..... |
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Lurch77 Premium Member join:2001-11-22 Green Bay, WI |
Lurch77
Premium Member
2010-Aug-28 6:22 pm
said by rex0:.......engineering..... That explains everything. |
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TheMG Premium Member join:2007-09-04 Canada MikroTik RB450G Cisco DPC3008 Cisco SPA112
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to 49528867
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! |
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neonhomerDearborn 5-2750 Premium Member join:2004-01-27 Edgewater, FL |
to 49528867
Is that 208-230, or 460?? LOL |
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cdruGo Colts MVM join:2003-05-14 Fort Wayne, IN |
cdru to Ken
MVM
2010-Aug-28 7:11 pm
to Ken
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? |
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dosdoxies Premium Member join:2004-12-15 Wallingford, PA 1 edit |
to rex0
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. |
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TheMG Premium Member join:2007-09-04 Canada MikroTik RB450G Cisco DPC3008 Cisco SPA112
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TheMG to cdru
Premium Member
2010-Aug-28 7:59 pm
to cdru
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? |
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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." |
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to cdru
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. |
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shdesignsPowered By Infinite Improbabilty Drive Premium Member join:2000-12-01 Stone Mountain, GA (Software) pfSense ARRIS SB6121
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shdesigns
Premium Member
2010-Aug-28 10:03 pm
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. |
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Jtmo Premium Member join:2001-05-20 Novato, CA 1 edit |
to 49528867
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..... |
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public join:2002-01-19 Santa Clara, CA |
to Ken
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 |
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dandeman MVM join:2001-12-05 Chapel Hill, NC |
to dosdoxies
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? |
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ITICharlie1Ass Mode Premium Member join:2003-01-22 Saint Louis, MO |
to 49528867
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. |
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49528867 (banned) join:2010-04-16 Fort Lauderdale, FL |
to theboz1419
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 |
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macsierra8Baby Newfoundland Premium Member join:2003-11-30 Minden, NV |
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... |
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49528867 (banned) join:2010-04-16 Fort Lauderdale, FL |
to ITICharlie1
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 |
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to TheMG
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. |
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rex0
Member
2010-Aug-29 2:11 pm
yes, yes it is |
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beyondo Premium Member join:2007-03-23 Seminole, FL |
to davidg
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... |
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Lurch77 Premium Member join:2001-11-22 Green Bay, WI
1 recommendation |
to Jack_in_VA
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. |
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61999674 (banned)Gotta Do What Ya Gotta Do join:2000-09-02 Here |
to beyondo
davidg was making a joke. |
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TheMG Premium Member join:2007-09-04 Canada MikroTik RB450G Cisco DPC3008 Cisco SPA112
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to Jack_in_VA
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. |
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to beyondo
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. |
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to Jack_in_VA
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. |
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n1zukmaking really tiny tech things Premium Member join:2001-10-24 Malta |
n1zuk
Premium Member
2010-Aug-29 9:26 pm
That air condition must be three phase. it has a Low, Med, and High setting. |
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