Autoformers
DB TECH
>voltmeter to get power readings when we go into a new RV park.
>Invariably, the reading will be at or near 115 V AC, which is
>too low to start up the air conditioning.
Your problem here is not 115 Volts, it is the fact that this
voltage drops considerably at start up and run because of poor
regulation due to the use of to small a wire gauge running a
long distance from the main box. The voltage may be dropping
below 80 volts at a high current start up.
>I can't believe how many parks seem to have substandard
>electrical hookups. As we look forward to our summer vacation,
>we were looking at the autoformer because it reported equalizes
>the highs and lows in voltage, keeping it around a constant 120
>V. We (and our pets) can't survive some of the places we plan
>to go to without air conditioning, and I don't want to take a
>chance on running the A/C on less than solid voltage, esp.
>since we just replaced the A/C.
>Camping World has a Hughes Autoformer for $419-$499 depending
>on features. Is this the standard cost for a product of
>this .sort? Is there any way we can come up with something for
>substantially less than that figure? What are your experiences
>with autoformers.
An autoformer/autotransformer is not a voltage regulator. It is
only a variable transformer.
i.e., set at 10% gain, it would raise any "input voltage" 10%,
period.
What you need ideally is an AC power conditioner. A power
conditioner will keep the output voltage constant (+ - 5%) even
with a 20% input voltage drop during A/C start up. The nominal
cost for these units is 75 cents per watt, so they're not
cheap. You would want a unit rated for the start current of the
A/C plus 20%, so this would be somewhat expensive, but it would
solve your problem at poorly wired RV parks. Be prepared to
spend possibly more than $2K for a quality/rated unit.
Dave Brownell
DB Technologies
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DB TECH
>go below that level when you turn the A/C on. It would seem
>that a gain of a set 10% would take care of most of our
>situations.
Keep in mind here that if you use an autotransformer set to a
higher output voltage with the A/C in mind, when the A/C
switches off you may be feeding 130 volts to other equipment
such as electronics, etc. Get an accurate AV voltmeter (2%) and
keep an eye on it.
Dave Brownell
DB TECH
>If you are getting 115 volts, you shouldn't have any trouble
>with your air conditioners. I would check the size, condition
>of your cable and connectors.
As I said earlier you could have 115 volts at no load with any
length small gauge power line.
With no load you could measure 115 volts at both ends of the
power line regardless of line length, however the voltage drop
under load could be tremendous even with the voltage at the box
remaining the same.
Owlman
Invariably, the reading will be at or near 115 V AC, which is too low to
have substandard electrical hookups. As we look forward to our summer
vacation, we were looking at the autoformer because it reported
equalizes the highs and lows in voltage, keeping it around a constant
120 V. We (and our pets) can't survive some of the places we plan to go
to without air conditioning, and I don't want to take a chance on
running the A/C on less than solid voltage, esp. since we just replaced
the A/C.
Camping World has a Hughes Autoformer for $419-$499 depending on
features. Is this the standard cost for a product of this sort? Is
there any way we can come up with something for substantially less than
that figure? What are your experiences with autoformers.
Thanx for your help.
Owlman
can so many parks (maybe 60+% of those we've gone to) be so far below standard
and yet everyone still seems to use the substandard electrical current? Are we
being unduly concerned?
Generally, the lower readings will be at or near 115 V and then go below that
level when you turn the A/C on. It would seem that a gain of a set 10% would
take care of most of our situations.
Thanx again for the help.
DB TECH wrote:
> >Do I understand correctly the use of this product? We bought a
> >voltmeter to get power readings when we go into a new RV park.
> >Invariably, the reading will be at or near 115 V AC, which is
> >too low to start up the air conditioning.
>
> Your problem here is not 115 Volts, it is the fact that this
> voltage drops considerably at start up and run because of poor
> regulation due to the use of to small a wire gauge running a
> long distance from the main box. The voltage may be dropping
> below 80 volts at a high current start up.
>
> >I can't believe how many parks seem to have substandard
> >electrical hookups. As we look forward to our summer vacation,
> >we were looking at the autoformer because it reported equalizes
> >the highs and lows in voltage, keeping it around a constant 120
> >V. We (and our pets) can't survive some of the places we plan
> >to go to without air conditioning, and I don't want to take a
> >chance on running the A/C on less than solid voltage, esp.
> >since we just replaced the A/C.
> >Camping World has a Hughes Autoformer for $419-$499 depending
> >on features. Is this the standard cost for a product of
> >this .sort? Is there any way we can come up with something for
> >substantially less than that figure? What are your experiences
> >with autoformers.
>
> An autoformer/autotransformer is not a voltage regulator. It is
> only a variable transformer.
> i.e., set at 10% gain, it would raise any "input voltage" 10%,
> period.
>
> What you need ideally is an AC power conditioner. A power
> conditioner will keep the output voltage constant (+ - 5%) even
> with a 20% input voltage drop during A/C start up. The nominal
> cost for these units is 75 cents per watt, so they're not
> cheap. You would want a unit rated for the start current of the
> A/C plus 20%, so this would be somewhat expensive, but it would
> solve your problem at poorly wired RV parks. Be prepared to
> spend possibly more than $2K for a quality/rated unit.
>
> Dave Brownell
>
> DB Technologies
>
MrRagtime
conditioners. I would check the size, condition of your cable and connectors.
Way back in 1958, the National Electric Industrification Council, a group
organized by the power companies around the country, standardized on 120, 208,
240 and 480 nominal voltages. However, 115 volts is considered 'within
tolerance' by most power companies.
The rating plates on your air conditioners are probably labelled 110-120 volts.
Neon John
Owlman wrote:
>
> Thanx for your comments. Anything in the $2K area is out of reach for us. How
> can so many parks (maybe 60+% of those we've gone to) be so far below standard
> and yet everyone still seems to use the substandard electrical current? Are we
> being unduly concerned?
>
> Generally, the lower readings will be at or near 115 V and then go below that
> level when you turn the A/C on. It would seem that a gain of a set 10% would
> take care of most of our situations.
Your AC should start on 115 volts. It should start as low as
105-109 volts. If it isn't, you need to run down the cause.
One cause could be a defective start capacitor (if it has one) or
starting relay (again, if it has one). Need to check that out
first.
Another cause may be excessive voltage drop during the starting
inrush. You need to hook your RV to a good, solid power source and
then take a digital voltmeter with peak/hold and track down the
starting voltage at each step. (the peak/hold will store the peak
and the valley voltage during the test interval) First, check the
voltage at the compressor terminals. If the voltage is OK there,
then you need to look elsewhere for the problem. Hook up the
voltmeter, activate the peak/hold function and start the unit. If
the voltage at the compressor stays above about 105 volts during
starting, it is OK. If not, work back. Test the voltage at the
unit's terminals. A high resistance thermostat contact or selector
switch contact could drop enough voltage to cause the problem. If
the voltage is OK there, go back to the breaker panel. If the
voltage is still low here, it could be a bad power cord. Does your
power plug get warm when the AC is on? If so, there's voltage drop
there.
You could have a tight compressor. Not a frequent occurrence but it
does happen. This manifests itself as difficult starting, high
starting current and perhaps a bit higher run current. The start
current should be less than the locked rotor current (LRA) listed on
the nameplate. If it's at or near the LRA, then either the
compressor is tight or the start device is defective. Takes an
amp-clamp with peak/hold to see this.
If the voltage at the compressor is marginal and/or the compressor
is tight, a possible solution is a hard start pack. This is a
capacitor and relay assembly that is designed to aid undervoltaged
or tight compressors start. Commonly known by the trademark
"KickStarter". Available at HVAC supply stores. Installation is
straightforward - just hook across the compressor terminals. The
kickstarter has the added benefit of reducing the starting current.
John
--
John De Armond
johngd...@bellsouth.net
http://personal.bellsouth.net/~johngd/
Neon John's Custom Neon
Cleveland, TN
"Bendin' Glass 'n Passin' Gas"
W F Sill
>Do I understand correctly the use of this product? We bought a
>voltimeter to get power readings when we go into a new RV park.
>Invariably, the reading will be at or near 115 V AC, which is too low to
>start up the air conditioning.
As others have indicated, 115v is adequate IF there is wiring capacity
to keep it close to that when your ac tries to start. If the CG wiring
is too small to start your ac now, it is almost certainly not going
to handle the extra load imposed by the transformer. . . . and as
someone else pointed out, when the accuts off you could easily have
too much voltage.
Will KD3XR ---- the Curmudgeon of Sill Hill
"This country was founded by religious nuts with guns".
P.J. O'Rourke
Ben Franklin VI
generator (all night if necessary) -- if NO other solution. be sure your
equipment is OK first.
we have only had one sub standard hookup, that was1998 at north phoenix
campground. the meter was rigged to run double speed. -- that was rectified
-- we retested it in 99.
>Subject: Autoformers
>From: Owlman owl...@home.com
>Date: 5/22/00 10:08 PM Central Daylight Time
>Message-id: <3929F635...@home.com>
>
>Do I understand correctly the use of this product? We bought a
>voltimeter to get power readings when we go into a new RV park.
>Invariably, the reading will be at or near 115 V AC, which is too low to
>start up the air conditioning. I can't believe how many parks seem to
>have substandard electrical hookups. As we look forward to our summer
>vacation, we were looking at the autoformer because it reported
>equalizes the highs and lows in voltage, keeping it around a constant
>120 V. We (and our pets) can't survive some of the places we plan to go
>to without air conditioning, and I don't want to take a chance on
>running the A/C on less than solid voltage, esp. since we just replaced
>the A/C.
>
>Camping World has a Hughes Autoformer for $419-$499 depending on
>features. Is this the standard cost for a product of this sort? Is
>there any way we can come up with something for substantially less than
>that figure? What are your experiences with autoformers.
>
>Thanx for your help.
>
>
>
>
>
>
>
.
.
"He that falls in love with himself will have no rivals."
(Franklin 1706-1790)
My way or the Highway! --- Ben ---
Hugh
Hugh
Owlman wrote:
>
> Let me first clarify from original post that we have NO problem with our
> A/C starting up at all. All that happens is that IF we start up the unit
> with a voltage of 115, it drops to maybe 110 when it's on high--maybe 112
> when on low. Previously on this board, I had been told that anytime you
> drop below 115 and stay there, that is bad. Our voltimeter shows green
> down to 115 and red below that level. Most of the parks we go to have
> initial voltage readings in the 115 to 118 area, but drop below 115 when
> the A/C is switched on.
>
> Some of you seem to be telling me that this may not be as bad for our unit
> as I had been led to believe. I don't think I've ever seen the reading go
> below about 108 or 109 even in the worst electrical hookups.
>
> Hope that clarifies somewhat my initial question.
>
> Thanx much.
>
> Nick Simicich wrote:
>
> > On Mon, 22 May 2000 21:47:20 -0700, DB TECH
> > <dbtekN...@juno.com.invalid> wrote:
> >
> > >What you need ideally is an AC power conditioner. A power
> > >conditioner will keep the output voltage constant (+ - 5%) even
> > >with a 20% input voltage drop during A/C start up. The nominal
> > >cost for these units is 75 cents per watt, so they're not
> > >cheap. You would want a unit rated for the start current of the
> > >A/C plus 20%, so this would be somewhat expensive, but it would
> > >solve your problem at poorly wired RV parks. Be prepared to
> > >spend possibly more than $2K for a quality/rated unit.
> >
> > I wonder if a honking computer UPS would be a simpler or cheaper
> > solution. Something like a Smartups that will boost voltages and so
> > forth. Biggest one I have is a 1400 KVA. Cost under $500. But if you
> > are talking $2k, you could probably go lots larger, for less.
Owlman
W F Sill
>Some of you seem to be telling me that this may not be as bad for our unit
>as I had been led to believe. I don't think I've ever seen the reading go
>below about 108 or 109 even in the worst electrical hookups.
I love it when a questioner gets the right message!
Chris Bryant
<392B46B3...@home.com>,Owlman wrote:
>Let me first clarify from original post that we have NO problem with our
>A/C starting up at all. All that happens is that IF we start up the unit
>with a voltage of 115, it drops to maybe 110 when it's on high--maybe 112
>when on low. Previously on this board, I had been told that anytime you
>drop below 115 and stay there, that is bad.
<<..>>
>
>Some of you seem to be telling me that this may not be as bad for our unit
>as I had been led to believe. I don't think I've ever seen the reading go
>below about 108 or 109 even in the worst electrical hookups.
I'm with the others- I wouldn't worry about it. Most A/Cs are
rated from 109 volts to 125 volts. (You also might check your power at
home just to see how accurate the voltmeter is- I've found the plug in
ones aren't all that accurate).
Back when I was traveling full time- I wouldn't worry about
the voltage- I just wanted to be cool. The only time our air wouldn't
run was at a place (not a CG) with 95 volts- the air would run for
about 10 minutes and then blow the breaker in the trailer.
In real bad situations, you would be surprised at how big a
difference turning the refrigerator to LP can make- a couple of years
ago, when we were staying in our trailer here, the power would get
real bad- down to 103 volts. If I turned the fridge to LP, we would
gain a good 5 volts- plus with low voltage, the fridge didn't work as
well.
--
Chris Bryant
Bryant RV Services- DeLand, Florida mailto:brya...@totcon.com
On RVing- TV about RVs, by RVers
Sylvan Butler
>Let me first clarify from original post that we have NO problem with our
>A/C starting up at all. All that happens is that IF we start up the unit
>with a voltage of 115, it drops to maybe 110 when it's on high--maybe 112
>when on low. Previously on this board, I had been told that anytime you
I don't know why you would have been told that. You should be fine.
>Some of you seem to be telling me that this may not be as bad for our unit
>as I had been led to believe. I don't think I've ever seen the reading go
>below about 108 or 109 even in the worst electrical hookups.
I wouldn't be worried about that unless you started blowing breakers or
other overload cutouts were triggered. (Motor current goes up as
voltage drops, thus low voltage can trigger breakers or overheat trips.)
My home power is often around 110, especially in the summer when the
irrigation pump and the well pump and the heat pump are all going full
capacity. Add in the neighbors all doing the same thing and I'm sure
the power company is losing a lot of wattage in the wires on their side
of the meter, but they don't seem to care.
I do see the voltage as high as 122 so it isn't just a matter of them
selecting a different tap on the transformer.
sdb
--
More guns means less crime. ISBN:0-226-49363-6
***
Watch out for munged e-mail address.
User should be sylvan and host is cyberhighway.net.
Do NOT send me unsolicited commercial e-mail (UCE)!
Owlman
rec.outdoors.rv-travel . . . you've come through again!!!
Thanx much all.
Stan
San Diego, CA
G Sanders
>
> I'm with the others- I wouldn't worry about it. Most A/Cs are
> rated from 109 volts to 125 volts. (You also might check your power at
> home just to see how accurate the voltmeter is- I've found the plug in
> ones aren't all that accurate).
>
> Back when I was traveling full time- I wouldn't worry about
> the voltage- I just wanted to be cool. The only time our air wouldn't
> run was at a place (not a CG) with 95 volts- the air would run for
> about 10 minutes and then blow the breaker in the trailer.
>
> In real bad situations, you would be surprised at how big a
> difference turning the refrigerator to LP can make- a couple of years
> ago, when we were staying in our trailer here, the power would get
> real bad- down to 103 volts. If I turned the fridge to LP, we would
> gain a good 5 volts- plus with low voltage, the fridge didn't work as
> well.
Excellent advice, Chris!
I'd just like to amplify on a couple of items - You're absolutely
right when you say the little analog plug in voltmeters aren't
known for their accuracy - we used to be driven crazy in our
campground with people complaining about "low voltage" using
these things. When we'd go to the site and check the voltage
with a good DVM, the voltage would be in the acceptable range.
Which is not to say that our campground didn't occasionally
experience low voltage, which leads me to the next item. When
we'd have low voltage (REALLY hot weather, and lots of rigs
with 2 A/C's, electric water heaters, etc.), in addition to
asking the guests to run the refer on LP, we'd also ask them
to not use the electric heater element on the hot water tank
if they had one. Some of these things use almost as much
current as an air conditioner.
A lot of campgrounds were built in a time when RV's weren't
loaded to the gills with every electrical appliance known to
man. And updating the electrical service is an incredibly
expensive proposition for the owner.
--
Gary Sanders
Bait for spammers:
root@localhost
postmaster@localhost
admin@localhost
abuse@localhost
postm...@127.0.0.1
pas...@cloud9.net
: Thanx much all.
: Stan
Stan, let me add one more item to all the good advice you have gotten from
the others on this ng.
In cases where a genuinely incorrect voltage situation exists for an
extended period of time, it is possible to boost (or even drop) line
voltage relatively inexpensively (certainly for a LOT less than $400) by
3, 6, or 12 volts by the use of a properly-wired low voltage transformer
which can handle the total a/c current. I won't provide any more
information on this here, as improper wiring could conceivably kill
someone, and besides, such an addition would probably violate the national
electrical code, UL approval, and all sorts of other things.
This sort of thing can be perfectly safe if done properly, but highly
hazardous if done wrong. I would suggest that anyone in need consult a
good electrical engineer, preferably someone with lots of experience in
power wiring. If he needs a hint on what I am talking about, mention the
numbers 6.3 or 12.6 to him.
Pete
G Sanders
>
> If he needs a hint on what I am talking about, mention the
> numbers 6.3 or 12.6 to him.
>
Ah yes, the old "buck/boost" trick!
Neon John
G Sanders wrote:
>
> pas...@cloud9.net wrote:
> >
> > If he needs a hint on what I am talking about, mention the
> > numbers 6.3 or 12.6 to him.
> >
>
> Ah yes, the old "buck/boost" trick!
Yep. But autotransformers are still cheaper, smaller and lighter
for a given KVA. Not from $CW$. Electrical supply houses are the
places to look.