EMS 50C

[Richard Hayden]

Ralph,
I'm the one who reported the death of the tv from a generator problem. That was
on our previous '81FC. I have also experienced a generator output problem on
our current '87PT. Our genset on this bus is a 8kw Power Tech and the "brain
board" suddenly quit causing very high voltages. On our previous bus the
generator was the standard Kohler 12.5kw. As on all arrangements on BB's, it
had its own breaker box close to the unit. You are correct, these thing must be
maintained. What happened on the '81 was the screws in the breaker box worked
loose over time to the point that they were not making continuous contact.
Hence the spikes and the demise of the tv. When the brain box failed on the
'87, I turned it off as soon as I noticed the voltage was very high and was very
lucky that apparently there were no appliances on line at the time since nothing
quit working. Obviously, my reaction time can't match that of any protective
device so I was just lucky.

But, you are correct, it is a matter of choice and that is why both
configurations are available.

Respectfully,

Dick Hayden - '87 PT 38 - Lake Stevens, WA


----- Original Message -----
From: Ralph L. Fullenwider
To: WanderlodgeForum@yahoogroups.com
Sent: Monday, March 26, 2007 1:01 PM
Subject: Re: [WanderlodgeForum] Re: EMS 50C


Hello Bill and All:

My thoughts on the EMS did not and does not pit one system against another
of the same ilk. Both have value albeit of different inputs and of course
lifestyles and present equipment.

With the unfortunate experience Ernie braved on his power cable, we have
all learned a very valuable lesson, and that is preventative maintenance. I
agree, that I missed the most obvious of things time> that the portable unit does not check the power cord or gen set
incoming power. So I will attempt to separate my thoughts on each matter.
These units are good, no doubt but not a wiz bang cure all and the interior
parts are subject to the same amperage overloads as any other system.
Amperage translates into heat and heat translates to predicted mean time
failure for relays, contacts and electronic parts. We all know that relay
contacts, over time will discolor with heat aka amperage, then progress
from there to pitting of the contact surface thus an actual welding of
those very contacts that protects down stream systems by opening and thus
stopping the damaging amperage (spike). Ok, I doubt there is a study on the
mean time fail rate or percentage of that type of failure.

While true, the portable will only do a partial job, but is not the main
theme here and of these units to disconnect when a power spike or surge
comes from the errant power source in an RV park?

Until one of the members reported that his gen set caused the death of a TV
set, I had not, in 10 years, seen this happen. Some things I tend to take
for granted, such as clean power from gen sets because, unlike RV parks, it
is a steady known source of power for our coaches. I tend to stay with the
thought, "I have to trust some things, and the gen set is one of
those." And also tend to go with the percentage of failure and the gen
sets are on the VERY low end of the fail scale. We have learned, on this
Forum, over the years, that proper maintenance of the gen set is mandatory
to maintain a steady known source of power and I see no reason to have to
protect from that source. That is my opinion only and perhaps flawed, but
perceived to be a truism.

We are also talking about 2 major types of input switching in these coaches
as well. That is the manual transfer switch and the automatic transfer
switch (ATS) The first, manual, is owner controlled as to the power being
allowed into his coach. The latter (ATS) is not owner controlled. Having
separated those two, My thoughts go to the two types of EMS units. One the
portable and the other the hard wired. The portable, for the manual
transfer switch will work the job of the intended use, and that is checking
the incoming power in the RV park pedestal and can be checked prior to
switching the manual transfer switch to allow the power into the coach.
While on the other hand, those coaches with the (ATS) do not have that
luxury and I agree, the hard wired is the best choice for those coaches.
and offer a better protection. Save for the forgotten power cord, which is
not checked, I still belive that either or will get the main job done for
the manual coach.

Any system can be taken to the point of over kill. What I don't know about
this EMS unit, is will it shut down with an over amperage down stream as
well as incoming? If it does then, in staying with the original theme of
"protection" from errant RV park power, both units, each in it's particular
usage get's the job done. If not, then the EMS does have a fault that can
fail.

Bottom line, the EMS is a GOOD thing but not a cure all and life style and
choice becomes the deciding factor. It is hard to believe that MOV's and
POV's will burn and open as they are designed to do in under a millisecond.
And a millisecond is all that is needed for a huge power spike to take out
sensitive electronic systems even though protected. A huge spike of voltage
or amperage will actually bridge and air gap of 1/2 inch or less no matter
if a relay contact is open or closed, but then that is going off the deep
end of the far side of the scale. I have not seen a POV or MOV that reacts
in the nano second range as this unit advertises. (still old school here on
that)

Apologies for this being so long winded, it is just some thoughts on the
subject. It still comes down to what each owner is comfortable with and
works best for him or her.

Safe travels,

Ralph and Charolette Fullenwider
84FC35
Ralph's RV Solutions, Duncan, Oklahoma

At 01:45 PM 3/25/2007 -0700, you wrote:
>BIG MISTAKE going with the portable unit.
>As I said in another post, the hardwire one will also check the portable
>cable which is usually the biggest problem on the electrical side.
>Ralph, can you explain yourself, why you would think the portable one is
>better, as the I think the portable one would only do a partial job.
>
>Bill 84 FC 35 SB "$quanderlodge"
>Terrace, B.C. Canada
>
>





[Non-text portions of this message have been removed]