John Baymore on thu 29 jul 99
------------------
(snip)
Last month I set the controller and went to bed. That was the last time
until I get an alarm to ring, buzz or clang if the power goes off. There
was
a slight power interruption and the controller shut down with =22error=22 on
the
screen. The kiln wasn't finished and really set my schedule back during a
busy time. Does anyone have any idea how we could go about making an alarm
that I could plug into the outlet in the bedroom?
Sure would appreciate ANY ideas.
(snip)
Bobbi,
Not sure, but I bet there is something that might do this for you in a
=22plug -in=22 consumer appliance from a place like Radio Shack.
Lacking that ....... this is a function that I often build into the flame
safety systems for fuel burning kilns I install....but it requires a little
comfort with some electrical stuff. Actually, it is done a little
different on a fuel kiln's flame safety ..... but this description is
=22close enough for government work=22 =3Cg=3E. Any licenced electrician =
should be
able to do this for you from the description below. Or at least they
will if I write it OK =3Cg=3E. I'll describe it based on a fuel fired kiln =
as
well.....but it works for electrics too.
In the AC supply for the all the kiln combustion support (combustion air
blower, flame safety system, main gas solenoid, etc) .....or on the AC
supply for an electric kiln.............you place a relay that is powered
to be held closed by the supply (house) current on the same circuit as the
kiln. Then on the secondary contacts of that relay you place a buzzer
(alarm) powered by a battery power supply (if the AC goes out the alarm
STILL needs power =3Cg=3E). The circuit of the alarm contacts is held OPEN
(no contact made) as long as there is AC power to the relay. When the AC
goes out, the relay itself then opens ....... this opening of the relay
then CLOSES the contacts on the alarm circuit, so that power flows in the
alarm circuit. The alarm sounds and wakes you up, and you bump your head
on the nightstand and you can't remember where you are for a few seconds
=3Cg=3E. The you run down to the kiln, swearing all the way =3Cbg=3E.
The alarm can be remote-ed to a great distance from the relay with a piece
of wire with two conductors. With big enough diameter wire on the alarm
circuit....... probably much father than you'd even dream. If you don't
want to have to remember to change (or check) the battery in the alarm
power circuit, you'll need to add a trickle charge function to the alarm
battery circuit and use nicads or gel cells to power it. That battery
charging part of the idea, if you want it, is a definite =22offf the =
shelf=22
purchase at Radio Shack.
The relay needs to be sized to be for the correct main power voltage. You
can get them to be run on the 208/217/220 VAC that powers your electric
kiln directly, but they are more expensive than ones for 110VAC. If it is
on the 2XX VAC kiln circuit you would also gain the function of an alarm
also going off if ONLY the power to the kiln istelf went out......poped a
breaker or whatever. You could also set up something that covered either
1XX VAC leg of the 2XX VAC kiln circuit going out........oops.... off on a
tangent =3Cg=3E. It is probably enough in your case to have it powered by =
the
wall socket AC for the whole house. A little cheaper to do too.
You can get the necessary relay for (nominal) 110V at Radio Shack, I think.
Or for sure from WD Grainger's. When under power, the relay contacts (the
alarm circuit) need to be OPEN...... no circuit completed. What is called
a =22single pole, single throw=22 set of contacts is all that is necessary,
although you could use a relay that had multiple contacts and just use one
set. The rating on the contacts of the relay has to be for the voltage and
current for the buzzer (alarm) circuit. Likely this will be 12V (or
whatever voltage buzzer you pick) and the current is probably so low (look
at the buzzer specs of the one you select) that most any 110V actuated
relay you will easily find will do.
The alarm bell/buzzer is available from Radio Shack....or WD Graingers.
Many choices....not really critical. Probably go for a pizieo
type....loud, annoying, and low voltage and current drain. Because it is
low voltage and low current you can use pretty minimal wiring from the
relay to the alarm. If it si not too far a run, you can use use simple
=22twisted pair=22, =22lampcord=22, or stereo speaker type wiring (unless =
you are
in a situation where building =22Code=22 issues apply).
However, one problem that could crop up here is the =22speed=22 at which the
relay will drop out compared to the digital controller (solid state). A
voltage drop sufficient to =22kill=22 the controller might be so fast (micro=
to
milliseconds) that the relay will not notice it and the power will be back
on before it actually opens. In this case, you'd need to build in a solid
state equivalent of this same power interuption/alarm circuit.....but it'll
react in a similar manner to the kiln controller. This is a little more
sophisticated....... not a do it yourself project........unless you are a
soldering iron jockey as well as a potter.
If you just wnat to protect from the power going out for about a second or
more....the above relay system will suffice. If you are having regular
problems with really short transient electrical faults..... you'll have to
go solid state.
Call the kiln manufacturer and ask them how =22fast=22 a voltage drop the
controller will react to. That'll give you a figure to shoot for. The
solid state alarm circuit will have to react the same or faster. If it is
faster, you'll get some false alarms. If it is slower..... the controller
will stop but the alarm won't go off.
Look in the local phone directory for the local ham radio club. If nothing
is there, go to the local Radio Shack.....they'll know who to contact=21
One of the hams could build you this solid state circuit very easily. It
is really a =22nothing=22 electronically. Simple stuff. Maybe trade a pot =
or
two for the =22little black box=22 which you'll plug into the AC plug and =
hook
the battery and alarm circuit to =3Cg=3E.
Hope this points you in a useful direction.
BEst,
......................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752
JBaymore=40compuserve.com
John.Baymore=40GSD-CO.COM
=22Earth, Water, and Fire climbing kiln firing workshop Aug. 20-29,1999
-one space available=22
elizabeth l gowen on fri 30 jul 99
John, thanks for the description of the system. I had some one I used to go
out with build a system for me 4 years ago, and couldn't remember some of
the details. I fire at night to get better electric rates ( a time of use
meter ) but I like to heat soak at the end of the firing, and was tired of
setting the alarm to get up early and wait for the setter to drop. He cut
the system into the electrical box on the kiln and put a little socket to
the outside of the box. I plug in a wall mounted unit with an on off switch
to this, and that unit is plugged into the wall socket. We attached a loud
alarm in the studio and a second one not as loud into the bedroom. The
latter has an on off switch so it can be silenced right away, and was run
with bell wire across the attic into the bedroom.
I love it and wouldn't want to fire without it. It also allows me to do
other stuff outside the studio while waiting for it to go off. I generally
don't stay in because of the excess heat in the studio, and extra fumes the
envirovent doesn't get. It also alarms when the electric goes off, from the
source not just the kiln setter, so would work for folks for that purpose.
It allows me to fire by cone rather than temp without a programmable unit/
I bought an early Baily, very expensive, hard to program, no key pad, and
not much support from the co. I use it mostly as a pyrometer now ,)
The extra socket on the kiln is nice when taking rings off to move or
rewire the kiln, less to tangle. All the parts were purchased from radio
shack. Check out the loudness of the alarm if putting in the bedroom. The
one in the studio would give me a heart attack if I were sleeping and it
went off, but can be heard in the house from a closed garage door.
-----Original Message-----
From: John Baymore
To: CLAYART@LSV.UKY.EDU
Date: Thursday, July 29, 1999 5:10 PM
Subject: Kiln alarm
----------------------------Original message----------------------------
------------------
(snip)
Last month I set the controller and went to bed. That was the last time
until I get an alarm to ring, buzz or clang if the power goes off. There
was
a slight power interruption and the controller shut down with "error" on
the
screen. The kiln wasn't finished and really set my schedule back during a
busy time. Does anyone have any idea how we could go about making an alarm
that I could plug into the outlet in the bedroom?
Sure would appreciate ANY ideas.
(snip)
Bobbi,
Not sure, but I bet there is something that might do this for you in a
"plug -in" consumer appliance from a place like Radio Shack.
Lacking that ....... this is a function that I often build into the flame
safety systems for fuel burning kilns I install....but it requires a little
comfort with some electrical stuff. Actually, it is done a little
different on a fuel kiln's flame safety ..... but this description is
"close enough for government work" . Any licenced electrician should be
able to do this for you from the description below. Or at least they
will if I write it OK . I'll describe it based on a fuel fired kiln as
well.....but it works for electrics too.
In the AC supply for the all the kiln combustion support (combustion air
blower, flame safety system, main gas solenoid, etc) .....or on the AC
supply for an electric kiln.............you place a relay that is powered
to be held closed by the supply (house) current on the same circuit as the
kiln. Then on the secondary contacts of that relay you place a buzzer
(alarm) powered by a battery power supply (if the AC goes out the alarm
STILL needs power ). The circuit of the alarm contacts is held OPEN
(no contact made) as long as there is AC power to the relay. When the AC
goes out, the relay itself then opens ....... this opening of the relay
then CLOSES the contacts on the alarm circuit, so that power flows in the
alarm circuit. The alarm sounds and wakes you up, and you bump your head
on the nightstand and you can't remember where you are for a few seconds
. The you run down to the kiln, swearing all the way .
The alarm can be remote-ed to a great distance from the relay with a piece
of wire with two conductors. With big enough diameter wire on the alarm
circuit....... probably much father than you'd even dream. If you don't
want to have to remember to change (or check) the battery in the alarm
power circuit, you'll need to add a trickle charge function to the alarm
battery circuit and use nicads or gel cells to power it. That battery
charging part of the idea, if you want it, is a definite "offf the shelf"
purchase at Radio Shack.
The relay needs to be sized to be for the correct main power voltage. You
can get them to be run on the 208/217/220 VAC that powers your electric
kiln directly, but they are more expensive than ones for 110VAC. If it is
on the 2XX VAC kiln circuit you would also gain the function of an alarm
also going off if ONLY the power to the kiln istelf went out......poped a
breaker or whatever. You could also set up something that covered either
1XX VAC leg of the 2XX VAC kiln circuit going out........oops.... off on a
tangent . It is probably enough in your case to have it powered by the
wall socket AC for the whole house. A little cheaper to do too.
You can get the necessary relay for (nominal) 110V at Radio Shack, I think.
Or for sure from WD Grainger's. When under power, the relay contacts (the
alarm circuit) need to be OPEN...... no circuit completed. What is called
a "single pole, single throw" set of contacts is all that is necessary,
although you could use a relay that had multiple contacts and just use one
set. The rating on the contacts of the relay has to be for the voltage and
current for the buzzer (alarm) circuit. Likely this will be 12V (or
whatever voltage buzzer you pick) and the current is probably so low (look
at the buzzer specs of the one you select) that most any 110V actuated
relay you will easily find will do.
The alarm bell/buzzer is available from Radio Shack....or WD Graingers.
Many choices....not really critical. Probably go for a pizieo
type....loud, annoying, and low voltage and current drain. Because it is
low voltage and low current you can use pretty minimal wiring from the
relay to the alarm. If it si not too far a run, you can use use simple
"twisted pair", "lampcord", or stereo speaker type wiring (unless you are
in a situation where building "Code" issues apply).
However, one problem that could crop up here is the "speed" at which the
relay will drop out compared to the digital controller (solid state). A
voltage drop sufficient to "kill" the controller might be so fast (micro to
milliseconds) that the relay will not notice it and the power will be back
on before it actually opens. In this case, you'd need to build in a solid
state equivalent of this same power interuption/alarm circuit.....but it'll
react in a similar manner to the kiln controller. This is a little more
sophisticated....... not a do it yourself project........unless you are a
soldering iron jockey as well as a potter.
If you just wnat to protect from the power going out for about a second or
more....the above relay system will suffice. If you are having regular
problems with really short transient electrical faults..... you'll have to
go solid state.
Call the kiln manufacturer and ask them how "fast" a voltage drop the
controller will react to. That'll give you a figure to shoot for. The
solid state alarm circuit will have to react the same or faster. If it is
faster, you'll get some false alarms. If it is slower..... the controller
will stop but the alarm won't go off.
Look in the local phone directory for the local ham radio club. If nothing
is there, go to the local Radio Shack.....they'll know who to contact!
One of the hams could build you this solid state circuit very easily. It
is really a "nothing" electronically. Simple stuff. Maybe trade a pot or
two for the "little black box" which you'll plug into the AC plug and hook
the battery and alarm circuit to .
Hope this points you in a useful direction.
BEst,
......................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
603-654-2752
JBaymore@compuserve.com
John.Baymore@GSD-CO.COM
"Earth, Water, and Fire climbing kiln firing workshop Aug. 20-29,1999
-one space available"
David Woodin on fri 30 jul 99
Mostly sounds good but the if the power comes back on again then the alarm
would stop so you need a circuit that won't reset by itself and has to be
manually reset.
David
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