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egg turner for an incubator

Hi there,

could someone with more of a brain than me help with a design for an
egg turner? basically i need to somehow use an RS 343-997 multi
function timmer that has an SPDT relay inside to control a motor that
will rotate CW untill a limit switch is pressed, then wait an hour
before rotating CCW untill another limit switch is pressed......wait
an hour and so on.

would it be possible? maybe with another SPDT relay wired parallel to
give me the contacts needed for polarity reversal?

i have to use this SPDT timer as i am on a very tight budget and have
it to hand!

This project is of a charitable nature for a kenyan village if i can
get it sorted out.

yours faithfully in advance,

levi
 
B

Bruce Varley

Jan 1, 1970
0
Hi there,

could someone with more of a brain than me help with a design for an
egg turner? basically i need to somehow use an RS 343-997 multi
function timmer that has an SPDT relay inside to control a motor that
will rotate CW untill a limit switch is pressed, then wait an hour
before rotating CCW untill another limit switch is pressed......wait
an hour and so on.

would it be possible? maybe with another SPDT relay wired parallel to
give me the contacts needed for polarity reversal?

i have to use this SPDT timer as i am on a very tight budget and have
it to hand!

This project is of a charitable nature for a kenyan village if i can
get it sorted out.

yours faithfully in advance,

levi


Someone may come up with something smarter, but I think you'll need a
bistable element as well as that timer, from a quick look at my ancient RS
catalogue.

The bistable element could be a toggle relay, one that changes it's output
contact state every time the input coil pulses on. I have a beautiful old
Omron with a 24VAC coil sitting on the shelf, if it'll assist you're welcome
to it for nix, just email. The local kids will watch it in fascination for
hours.

Wired so that motor is deenergised when either of the limit switches is
active, ie. the egg thing is at either extremity.

Set your timer to generate regular short on pulses, say 10 seconds,
separated by an hour (Asymmetric recycler mode if I read the book
correctly). Use that pulse to pulse the toggle relay, to reverse the
direction of the motor, and also to bypass the limit switch interlock. Thus
for 10 seconds, the motor runs despite the limit switches, but in a
direction that takes it away from the limit. By the time the pulse has
finished, the limit switch is clear, so the motor will keep running until it
hits the other switch, and stop.

Just another thought, if this really is for a poor Kenyan village, then this
RS component is a bit of an odd choice. Way over engineered for the task at
hand, and undoubtedly not cheap. Also, being electronic, it may not
appreciate the sort of power supply it may have to put up with. I'm sure
someone here will come up with something better.

[email protected] remove ecks and kyoo to email.
 
T

Tim Wescott

Jan 1, 1970
0
-- snip --
Just another thought, if this really is for a poor Kenyan village, then
this RS component is a bit of an odd choice. Way over engineered for the
task at hand, and undoubtedly not cheap. Also, being electronic, it may
not appreciate the sort of power supply it may have to put up with. I'm
sure someone here will come up with something better.

[email protected] remove ecks and kyoo to email.

A poor Kenyan comes to mind.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
 
B

Bruce Varley

Jan 1, 1970
0
Bruce Varley said:
Someone may come up with something smarter, but I think you'll need a
bistable element as well as that timer, from a quick look at my ancient RS
catalogue.

The bistable element could be a toggle relay, one that changes it's output
contact state every time the input coil pulses on. I have a beautiful old
Omron with a 24VAC coil sitting on the shelf, if it'll assist you're
welcome to it for nix, just email. The local kids will watch it in
fascination for hours.

Wired so that motor is deenergised when either of the limit switches is
active, ie. the egg thing is at either extremity.

Set your timer to generate regular short on pulses, say 10 seconds,
separated by an hour (Asymmetric recycler mode if I read the book
correctly). Use that pulse to pulse the toggle relay, to reverse the
direction of the motor, and also to bypass the limit switch interlock.
Thus for 10 seconds, the motor runs despite the limit switches, but in a
direction that takes it away from the limit. By the time the pulse has
finished, the limit switch is clear, so the motor will keep running until
it hits the other switch, and stop.

Just another thought, if this really is for a poor Kenyan village, then
this RS component is a bit of an odd choice. Way over engineered for the
task at hand, and undoubtedly not cheap. Also, being electronic, it may
not appreciate the sort of power supply it may have to put up with. I'm
sure someone here will come up with something better.

[email protected] remove ecks and kyoo to email.
Better ... no bistable relay required. Latch a normal relay on one limit
switch, delatch it on the other one. Use a contact from that relay to
control the motor direction.
 
M

Meat Plow

Jan 1, 1970
0
Better ... no bistable relay required. Latch a normal relay on one limit
switch, delatch it on the other one. Use a contact from that relay to
control the motor direction.

Or have a couple village kids rotate the eggs by hand like the Amish do.
--
#1 Offishul Ruiner of Usenet, March 2007
#1 Usenet Asshole, March 2007
#1 Bartlo Pset, March 13-24 2007
#10 Most hated Usenetizen of all time
#8 AUK Hate Machine Cog
Pierre Salinger Memorial Hook, Line & Sinker, June 2004
COOSN-266-06-25794
 
B

Brian

Jan 1, 1970
0
Hi there,

could someone with more of a brain than me help with a design for an
egg turner? basically i need to somehow use an RS 343-997 multi
function timmer that has an SPDT relay inside to control a motor that
will rotate CW untill a limit switch is pressed, then wait an hour
before rotating CCW untill another limit switch is pressed......wait
an hour and so on.

would it be possible? maybe with another SPDT relay wired parallel to
give me the contacts needed for polarity reversal?

i have to use this SPDT timer as i am on a very tight budget and have
it to hand!

This project is of a charitable nature for a kenyan village if i can
get it sorted out.

yours faithfully in advance,

levi

Eggs don't have to be turned back and forth. Rolling them works. Like
in the old round metal Brower incubators. Can use a clock motor (hour
hand).

Or, make some rollers the eggs rest on. Turn the rollors with a slow
motor.

Most cheap incubators do rock the eggs back and forth, but use a
unidirectional motor canged to bidirectional by the peg in groove
mechanical part.

Make sure your thermostat can sold within 1 F, thats way more
important. After 7 days or so, turning isn't even necessary anymore.
 
W

Wim Ton

Jan 1, 1970
0
Hi there,

could someone with more of a brain than me help with a design for an
egg turner? basically i need to somehow use an RS 343-997 multi
function timmer that has an SPDT relay inside to control a motor that
will rotate CW untill a limit switch is pressed, then wait an hour
before rotating CCW untill another limit switch is pressed......wait
an hour and so on.

would it be possible? maybe with another SPDT relay wired parallel to
give me the contacts needed for polarity reversal?

i have to use this SPDT timer as i am on a very tight budget and have
it to hand!

diode endswitch
------->|----/ -----| DC motor
AC-----/ |------O----- AC
--------|<---/ ----- |
diode endswitch
 
P

Paul Hovnanian P.E.

Jan 1, 1970
0
Hi there,

could someone with more of a brain than me help with a design for an
egg turner?

A spatula?
basically i need to somehow use an RS 343-997 multi
function timmer that has an SPDT relay inside to control a motor that
will rotate CW untill a limit switch is pressed, then wait an hour
before rotating CCW untill another limit switch is pressed......wait
an hour and so on.

would it be possible? maybe with another SPDT relay wired parallel to
give me the contacts needed for polarity reversal?

Simpler than that: Use a SPDT limit switch, arranged so that when the
egg roller reaches one
limit, it flips the switch to the opposite contact. When the motor
turns the other way, the limit switch remains as is until it reaches the
opposite limit, then flip back. Use the following circuit:


+V
|
Relay +---------------+---------------+ Limit switch
| |
| |
CCW command o o CCW Limit
\
\o--------- Motor ---------o\
\
CW command o o CW Limit
| |
| |
+---------------+---------------+
|
|
gnd
 
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