X10 Community Forum
🔌General Home Automation => Automating Your House => Troubleshooting Automation Problems => Topic started by: SteveRF on September 01, 2005, 08:05:58 PM
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Hello All,
Does anyone know how to mod an appliance
module so that a POWER FAILURE will result in
the module returning to the OFF state without
fail.
I have a small pump that I DO NOT want to
return to run status after a power failure.
On occassion after a power failure, the pump
fails to start and trips only after teh
thermal overload breaks. This is NOT good...
My other option, anyone know of a breaker
that will trip on power failure and require a
manual reset to restore ?
Regards,
SteveRF
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How much current are you talking about. I
have done a modification to a Lamp Module
that adds a solid state relay to it. Then it
can control inductive devices like motors
and cfls. Lamp Modules default to off when
the power is interupted. Down side could be
lamp modules will respond to an all lights
on command. So technically it could be
turned on in some cases by something like a
security consols all lights on signal when
triggered. Also if you try and dim the
address, it will not dim but when the normal
dim level is low enough the SSR just turns
off.
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http://www.idobartana.com/hakb/index.htm Is one site where the modifacations can be found and he has a link to tparents site where I found my mod. I did remove the local control components; though he did not. If more current is needed a larger SSR can be wired in if needed.
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Brian,
Thanks for the response...
The pump motor in question is 120VAC, 1/2 HP
As noted earlier, I am really looking for a
"failsafe" method to trip power after a power
loss so that the pump cannot restart without
a manual reset.
Thanks,
SteveRF
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You could probably modify an appliance
module by removing the relay and use a
normally off relay that is triggered by a
flip-flop connected to pin 6 on the PIC.
As for a breaker that will trip on a power
failure, you could check out emergency stop
switches sold to machine shops. I think
some of them will trip on a power failure.
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Rogers ideas may make better sense, if the
lamp module maybe not 100% fool proof.
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Steve,
How about using a 4PDT 120v ac coil relay,
with 1 pole wired as a self latch.
(momentary push button supplies 120V to coil
and two NO contacts of relay are wired
across push button. Once you push the button
relay remains closed until power
interuption. You will have to push button
again to relatch) Two poles wired to supply
power to the appliance module? "All
Electronics", and "MECI" have 20 amp 120v
coil relays for about $5. Radio Shark used
to also carry 120v coil relays.
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Dave; That sounds like a very good way to do
it. You still have X10 control with the
appliance module but on a power loss the AC
to the module stays off, untill reset.
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Roger, that sounds like a lot of mods...but
maybe workable.. Thanks
Dave W. THANKS !... sounds like a plan..good
idea.. I have already ordered a couple of
120vac relays , couple of momentary button
switches and a few other goodies that caught
my eye... I'll build it in a large receptacle
box so that I can include a receptacle and
just plug in the pump...WOW..good idea..
This forum is just full of nice folks with
good ideas !
Regards,
SteveRF
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SteveRF
Make sure the relay you ordered is rated
for your pump motor.
If you do not want to build one, there are
ready made fail safe box available for
power tools, electrical wholesale usually
carry them.
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Carmine,
Thanks for the tip... actually, I was looking
for a manufactured trip but was unable to
find one and was not sure it would be cost
efficient.
I have decided to go with the relay and have
a 12 amp 120vac in hand, mom push button
etc... my latest mod is to abandon carrying
the pump load thru the relay and simply use
the relay to cause a ground fault on that
circuit which will trip the ground fault
breaker... It may save my pump after a power
failure..because the power failures here are
always when I am not home (smile) or during a
hurricane (which I understand). Thanks for
the tip. Sometimes we do forget the obvious.
Regards,
SteveRF
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All,
The mod is complete... and works well.
Many thanks for all the ideas !
I used the relay to create an artificial
ground fault between the Neutral and Ground.
That condition tripped the Ground Fault
Breaker and required a manual reset to
restart my pump. Now I don't have to worry
about my pump failing to start up after a
brief power failure. Many Thanks to all...
Regards,
SteveRF
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Now that is a unique solution! Force a
ground fault. As long as someone else
doesn't try it and get the hot by mistake.
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Brian,
Your Right !
Maybe they will notice when the relay
contacts Spark and fuse together..smile
Hope they test using a GFI protected circuit.
SteveRF
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SteveRF:
If I have this straight: Power goes off;
relay closes; power comes back on; relay
causes ground fault; GFI opens circuit to a
1/2 HP pump motor which is drawing starting
current.
Good grief - it's easy to understand why
localities require licensed electricians to
do electrical work. Better not let the city
inspector get wind of your scheme.
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Charles Sullivan,
Well, you almost have it straight.
Power goes off, relay "opens", power bumps
back on and relay closes and causes a ground
fault from neutral to earth ground. This ver
minor fault causes a Gnd/Neu sensing GFI to
break thus leaving my pump safe until I
manually reset. Keep in mind that this mod
does not in any way involve rewiring
anything. I constructed a simple 3-wire plug
in module, protected in an approved inclosure
which simply plugs into any GFI protected
circuit receptacle. In my case, it was the
receptacle serving the pump motor. Bottom
line is that this method is very safe in that
the tripping current differential is only
about 4-7ma and can be plugged into the
existing protected circuit. If one has the
ability to wire receptacles correctly,
understand Hot, Neutral, Ground and white to
bright and black to brass...then it is safe
and may very well save my pump from starting
a fire.
SteveRF
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SteveRF: It may be “safe” when used in a
controlled environment, but I doubt if it
would receive CSA or UL approval since you
are relying on the GFI outlet to be wired
correctly. Also, I think GFI outlets are
designed to only be tripped occasionally.
The increase in number of trips may cause
it to fail prematurely. I would certainly
test the GFI after each power failure.
I am curious why you decided to use this
approach rather than having the relay
interrupt the circuit?
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I just re-read your description and if the
relay is closed when the power is on then
you are operating with a continuous ground
fault and if a real ground fault were to
occur, the GFI may not trip. Am I missing
something?
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SteveRF:
Have to agree that this is not a good plan.
Besides the other potential problems below,
if the GFI does not work properly (which can
happen), you have purposely created a ground
fault. In this case, add a defribrillator to
your tool kit. Suggest you return to the
relay idea (or something like it).
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The fact remains that you are using the GFI
in an unapproved manner which most likely
violates code. And if anything "goes wrong"
which can in any way be attributed to your
scheme, your insurance company will void your
homeowner policy and deny coverage.
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WOW..So many opinions...Thats good. If I
have better options then I may change it.
Roger H. It was my error in description: I
meant the relay was pulled in or energized
during operation thus eliminating the Neutral
to Ground fault. During a power failure the
fault causing contacts are closed. I agree
with you about testing the GFI device after
each power failure: That is exactly what my
device will do.. same as pushing the "test"
button on the GFI.
Bill H. I understand your thinking but that
is the purpose of the GFI device, to detect
an imbalance of as little as 7ma current flow
between the Hot, Neutral/Ground or the same
between Neutral and Ground. Mine tripped at
about 4ma. Basically, it is doing the same
thing an overheated pump might do but way
before burning up the pump or my home.
Another saving grace here is that this is an
isolated circuit, running from the breaker
panel outside directly to a small pumphouse
and terminating in a protected GFI device.
Charles, As far as using in an unapproved
manner, you may be correct but I am
essentially doing the same as pressing the
"test" button on the GFI device and causing a
momentary short. Except, the test button
shorts the Hot and Neutral through a 15k
resistor and I am using the neutral and
Ground sensing circuit, which is much safer.
Bill, I will order the Defib today..smile...
and now...
I actually do appreciate all the thoughts,
ideas and warnings... If I see one single
glitch I will unplug and report my device as
a failure.
Regards,
SteveRF
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Hey Steve!
I'm not going to weigh in on the propriety
of using the GFI to disable the pump, but
you said something that makes me think I do
not understand how a GFI works.
"Except, the test button shorts the Hot and
Neutral through a 15k resistor "
I thought a GFI tripped if there was a
differential between the current going out
the hot and current back through the
neutral. If not equal, the difference is
getting to ground through something or
someone, creating the trip.
If your GFI test switch shorts hot to
neutral through a 15K resistor, then the GFI
must also be looking for "small" currents
traveling the normal path?
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Dave W.,
The GFI that I have creates a current
differential between the HOT and Neutral
through a 15K resistor when pressing the TEST
button to simulate exactly what you said, a
momentary differece in current flow in the
Hot and Neutral. ( I should not have used the
word "short") When this condition is detected
then a trip is initiated...So you are
absolutely correct ! Most GFI's also sense a
difference between Neutral and Ground and
trip if more than (I think..7ma).. and you
are correct it can detect a very small
differential current flow. The one I am
using will actually trip between 2-4ma. I
hear some motors will actually cause GFI's to
trip when starting and can cause lots of
heartaches when using GFI's ... thank
goodness mine does not do that. I believe I
took the safe approach by using a Neutral to
Ground trip simulation. I read more every
day and I have also noted that most experts
suggest that you test often. I will
definitely do that ! I just decided that I
did not want to rely on the 12amp relay
carrying the pump load and decided to use it
to create a safe momentary fault condition
that would trip the GFI.
Considering that we use GFI's to protect our
lives, using it this way to protect a pump
made sense to me.
Thanks for your input and thoughts...
Everytime someone mentions something it makes
be check and double check this setup.
Obviously, I was going to use a X10 appliance
module at first but decided against that
route after some suggestions from the forum.
Many Thanks !
SteveRF
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How has this arrangement worked for you?