Go Back   Montana Owners Club - Keystone Montana 5th Wheel Forum > HAVE MOC WILL TRAVEL > The Campsite
Click Here to Login

Reply
 
Thread Tools Display Modes
 
Old 06-27-2018, 03:53 PM   #41
dfb
Montana Fan
 
Join Date: Mar 2015
Location: Gardnerville
Posts: 477
M.O.C. #17163
[QUOTE=BB_TX;1104159]You are not correct. It has been explained multiple times above.

Look at the circuit breaker. It is a two pole circuit breaker, 50 amps on each pole. 50 amps thru hot leg 1 plus 50 amps thru hot leg 2 = up to 100 amps 120 vac capability = up to 12,000 watts.

And it is 240 vac measured hot leg 1 to hot leg 2.

it is 12000 watts... but at 120 volts..


dfb is offline   Reply With Quote
Old 06-27-2018, 03:57 PM   #42
mtlakejim
Montana Master
 
mtlakejim's Avatar
 
Join Date: Oct 2017
Location: Bee Branch
Posts: 1,330
M.O.C. #20693
Thanks for all the discussion, good stuff!

The BIG thing I take away from all this is we as a group have a vested interest in pushing hard for RV park owners to upgrade their electrical systems!! I might be wrong but I suspect as a group we could at least be influential in a push for such improvements at State and Federally operated parks. Do we have any sort of mechanism within MOC for such action? If not, is there an RV organization that does?
__________________
James & Irene Wilson
Bee Branch, AR.
2017 Ram 1 ton diesel duallyCrew Cab/Long Bed
2018 Montana High Country 381TH Garage Full of Toys
mtlakejim is offline   Reply With Quote
Old 06-27-2018, 05:48 PM   #43
7.3Ford
Montana Master
 
7.3Ford's Avatar
 
Join Date: Oct 2009
Location: Indian Land
Posts: 1,084
M.O.C. #9808
Quote:
Originally Posted by mtlakejim View Post
So if they had the A/Cs on separate legs would you be able to run both at a 30amp site??
I have run both A/C on 30 amp breaker before. You just have to make sure water heater and fridge are on gas. Also don't turn the microwave.

The said, with Hybrid Inverter, and some mods you can run both A/C and the microwave for short periods of time.. See my blog for more info.
7.3Ford is offline   Reply With Quote
Old 06-27-2018, 07:19 PM   #44
Mark7
Established Member
 
Mark7's Avatar
 
Join Date: Sep 2016
Location: Fargo
Posts: 23
M.O.C. #19032
Quote:
Originally Posted by Phil P View Post


When you turned the first 20 amp load on line 1 the amp meter for line 1 and the amp meter for the natural will read 20 amps.

Then when you turn the second 20 amp load on line 2 you will read 20 amps on line 1 and 20 amps on line 2 and 0 amps on the natural.

The neutral only carries load when the loads are unbalanced.

Phil P
Please explain this Phil... I'm not arguing but I can't get my head around it. I can see the N being 0 amps if a single load is spanning the two legs, (240 V dryer) but if you have 2-120V loads on opposite legs, say two A/C's (one on each leg)... those 2 legs are 180˚ out of phase with each other, which is why a 240 V load spans them... the A/C on one leg is high while the other is low (60 times a second). If separate loads span those 2 phases, then they are 180˚ out of phase with each other, therefore using the N at 180˚ intervals.

Am I missing something here? I am never too old to learn!
__________________
2004 Montana 3295RK
1998 Dodge / Cummins 2500
Summer season weekend warrior
Mark7 is offline   Reply With Quote
Old 06-28-2018, 07:45 AM   #45
jlb27537
Montana Master
 
Join Date: Jan 2013
Location: Depends on temps
Posts: 1,633
M.O.C. #13157
Quote:
Originally Posted by dfb View Post
It's 6000 watts at a voltage of 120 volts..Instead of 3600 watts at 120 which is the same as most portable rv gensets.... Its' not 220.. its not 12000 watts.. It is 120 volts of 50 amp service.. 25 amps on each leg.. comes to 6000 watts... of equal portable generator or built in power...
You are Wrong. Question, if it is only 25a per leg, why are the breakers 50a? If it is only 25a why is #6 wire required?
jlb27537 is offline   Reply With Quote
Old 06-29-2018, 04:02 AM   #46
Phil P
Montana Master
 
Join Date: Mar 2011
Location: Okeechobee
Posts: 2,021
M.O.C. #11206
Mark7

Go back to the pictures of the step down transformer.

When a transformer is wired in this manner the center tap is used to operate a load that requires only half the voltage the transformer can produce. If you combine 2 loads (appliance) of equal load (amps) value on the wires L1 and L2 then the combined loads are viewed as one appliance needing twice as much voltage at the same amperage.

The inherent actions of AC electricity will just use the entire transformer and the neutral is no longer needed.

Let say you have a space heater that operates on 240V to produce radiant heat without a fan and this heater has 2 heating elements wired end to end or in series. If one element fails the heater quits working. However if you could provide a neutral line to the remaining working element it would continue to work on half the voltage but the same amperage.

These kind of applications combined with the ease of changing voltage with transformers is what makes AC so much more desirable than DC power.

The thing most of the end-users over look is the neutral is common to both line loads (appliances) on both line 1 and line 2.

This is also the reason that there is so much costly damage when the neutral is lost on these RV units. An unbalanced load of 10 amps on line 1 and 50 amps on line 2 with open neutral causes 50 amps to be passed thru the 10 amp load and the 10 amp load becomes a crispy critter. If this is you $1,000.00 TV you get the idea.

So the recommendations made by several of us about maintenance of you power cords and using a line conditioner like Progressive or Surge Guard is very good advice.

And you donít need to understand the working of AC power to take and use the advices.


Phil P
__________________
2009 Montana 3665RE
2009 Duramax 3500 DRW quad cab
personal web page https://www.sallyscoffees.com
If you get a page not available then remove the "s" after HTTP
Phil P is offline   Reply With Quote
Old 06-29-2018, 08:42 AM   #47
BB_TX
Montana Master
 
Join Date: Oct 2006
Location: McKinney
Posts: 4,472
M.O.C. #6433
Quote:
Originally Posted by Mark7 View Post
... those 2 legs are 180˚ out of phase with each other, which is why a 240 V load spans them... the A/C on one leg is high while the other is low (60 times a second). If separate loads span those 2 phases, then they are 180˚ out of phase with each other, therefore using the N at 180˚ intervals.
........
Mark - you are very close. Current flows back and forth in alternating directions thru a neutral just as it does thru a hot. But in the case of two equal loads on opposite phases using a common neutral wire, one load is trying to flow current into the neutral while the other is trying to flow current out from the neutral. Those currents are always alternating direction, but are always opposite of each other in the direction of flow. Current cannot flow both directions in the same wire at the same time. The result is that the those currents simply redirect thru the opposite load.

Note that current does flow thru the neutral wiring as far back as the neutral buss bar. Just not thru the power cord neutral wire.

Make sense? Or just confuse it more?
__________________
Bill & Patricia
& Molly (our 11 yr old Golden)
2007 3075RL
2012 F350 SRW CC LB FX4 6.7
BB_TX is online now   Reply With Quote
Old 06-29-2018, 10:44 PM   #48
firetrucker
Montana Master
 
Join Date: Oct 2004
Location: Gardnerville
Posts: 748
M.O.C. #2165
The case of two equal loads on the two phases is a very special case, but does illustrate the fact the the neutral does carry the sum of the two currents, one plus and one minus, but not always 180 degrees out of phase (remember power factor).

But the neutral cannot be eliminated, even in this special case, because it guarantees that there is always 120 volts across each circuit, what our equipment is designed for.

And, if one circuit carries 50 amps and the other 10 amps, and you lose the neutral, you cannot force the 10 amp load to carry 50 amps. For simplicity, let's assume resistive loads: 120 V/50 A=2.4 ohms and 120 V/10 A=12 ohms. When you lose the neutral, 240 V/14.4 ohms=16.7 amps through each load. That means the 2.4 ohm load sees 40 V (2.4 ohms x 16.7 amps) and the 12 ohm load sees 200 V (12 ohms x 16.7 amps) at least momentarily.

Real loads consist of resistive, capacitive, and inductive components which give a more complex result. But the math is fundamentally the same
firetrucker is offline   Reply With Quote
Old 06-30-2018, 06:34 AM   #49
Phil P
Montana Master
 
Join Date: Mar 2011
Location: Okeechobee
Posts: 2,021
M.O.C. #11206
Firetrucker

I see you have had the same training I have. Maybe you explanation is a little clearer than mine.

Now how about 120V 400 cycle thatís a different animal but very efficient. LOL

Phil P
__________________
2009 Montana 3665RE
2009 Duramax 3500 DRW quad cab
personal web page https://www.sallyscoffees.com
If you get a page not available then remove the "s" after HTTP
Phil P is offline   Reply With Quote
Old 06-30-2018, 01:00 PM   #50
rohrmann
Montana Master
 
rohrmann's Avatar
 
Join Date: Oct 2012
Location: Box Elder
Posts: 1,941
M.O.C. #12947
The only thing most folks need to know is, lose the neutral connection, whether inside the rig or anywhere in the system going to the rig, and you will likely burn up a number of devices and equipment. As a lineman, I have measured in excess of 180 volts on one leg at a house panel and less than 60 volts on the other leg, still 240 across the hots, and all this due to a poorly made splice in the service cable neutral. Fortunately, none of the customerís property was damaged in the one incident that Iím describing. Again, this really is all anyone really needs to know, and this can occur if the service is a 208 volt or a 240 volt.
__________________
Bob & Becky
2012 3402RL
2012 Chevy 2500HD D/A CC 4WD
rohrmann is offline   Reply With Quote
Old 06-30-2018, 01:53 PM   #51
BB_TX
Montana Master
 
Join Date: Oct 2006
Location: McKinney
Posts: 4,472
M.O.C. #6433
Bob - I fully agree with you. It is just that many of us (and I am betting you also) with inquiring minds really like to know the whys and what-fors of things we don’t fully understand.
__________________
Bill & Patricia
& Molly (our 11 yr old Golden)
2007 3075RL
2012 F350 SRW CC LB FX4 6.7
BB_TX is online now   Reply With Quote
Old 07-01-2018, 04:48 AM   #52
Phil P
Montana Master
 
Join Date: Mar 2011
Location: Okeechobee
Posts: 2,021
M.O.C. #11206
Hi Bob

Yes the point to the entire post is to stress the use of a line conditioner of some source and to periodically inspect and tighten the connections in the service cord, trailer receptacle and at the power panel inside the trailer.

As for the stick house I had my wife call me a few years ago and tell me the bathroom light got real bright when she tried to use the toaster. Fortunately none of the power sensitive appliances were on line.

Tuned out to be the aluminum neutral strap in the meter can. Of course this was on a weekend but the lineman goes to the same church as I and the local electrician I caught between church and going fishing and he had a new can in his truck.

Phil P
__________________
2009 Montana 3665RE
2009 Duramax 3500 DRW quad cab
personal web page https://www.sallyscoffees.com
If you get a page not available then remove the "s" after HTTP
Phil P is offline   Reply With Quote
Old 07-01-2018, 11:05 AM   #53
firetrucker
Montana Master
 
Join Date: Oct 2004
Location: Gardnerville
Posts: 748
M.O.C. #2165
I dealt with 400 cycle (Hz) power for many years, but that's a diversion. We're stuck with 60 Hz stuff for better or worse. And I won't use anything that's aluminum, unless there's no choice. I've also been involved with vibration measurements in all types of machinery.

Bottom line is, we seem to forget that if it vibrates, it will come loose, even though we're reminded of it everytime we take the rig out.

Always check critical systems, including electrical. A surge protector is nice, but even that can mislead you if you make assumptions. A cheap socket tester and visual inspection should be major items on your checklist that should not be skipped.
firetrucker is offline   Reply With Quote
Old 07-01-2018, 04:23 PM   #54
Phil P
Montana Master
 
Join Date: Mar 2011
Location: Okeechobee
Posts: 2,021
M.O.C. #11206
Quote:
Originally Posted by firetrucker View Post
I dealt with 400 cycle (Hz) power for many years,.

What were you working on when you worked with 400 cycles AC?

The thing I like about and the reason it is used in my industry is it turns a 5 HP continuous duty hydraulic pump motor in to a piece of equipment the size of the windshield wiper motor in your car.

Phil P
__________________
2009 Montana 3665RE
2009 Duramax 3500 DRW quad cab
personal web page https://www.sallyscoffees.com
If you get a page not available then remove the "s" after HTTP
Phil P is offline   Reply With Quote
Old 07-01-2018, 05:09 PM   #55
jeffba
Montana Master
 
Join Date: Oct 2017
Location: Bastrop
Posts: 697
M.O.C. #20753
LOL I have wound coils for a 25HZ motor. 20' (yes feet in diameter). USS Rail Mill
__________________
-----------------------------
2018 HC 379RD
2018 Ford F-350 Lariat CCLB PSD DRW OEM Puck
jeffba is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Powered by vBadvanced CMPS v3.2.3

All times are GMT -6. The time now is 07:10 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2018, vBulletin Solutions, Inc.