On Wed, 27 Jun 2007 11:38:15 -0700, "David Farber"
wrote:


"Ross Herbert" wrote in message
.. .
On Wed, 27 Jun 2007 07:39:10 GMT, Ross Herbert
wrote:


http://www.pbase.com/mrfixit/image/81163242


Midtex 15522T200 - Online Components
http://www.onlinecomponents.com/product/3123033
Appears to be 120V ac coil.


http://www.pbase.com/mrfixit/image/81163244

Midtex 15523Q200 - Online Components
http://www.onlinecomponents.com/product/3123040
Appears to be 24V ac coil

Midtex is now part of the Tyco brand stable but I can't locate the
part numbers on their site. Have requested specifications from
Tyco
if available. Will post result.


PS. Since you say there is no DC power supply then it would appear
that photo 1 also shows an ac coil relay.

Perhaps whoever worked on it before was replacing parts and not too
picky
about what types of relays were put in.

I have uploaded a schematic of the electronics which I drew from
tracing all
the wires. I'd like to know if anybody can find any mistakes in the
wiring
diagram.

http://www.pbase.com/image/81266775

Secondly, there is a bell hose that opens the gate from the inside of
the
garage and a key that opens the gate from the outside. There is a
second
hose whose sensor is not hooked up which runs underneath the gate
when in
the closed position. I think this is a safety factor in case somebody
drives
in and the gate starts to close and would prefer not having their car
smashed. As a security precaution, I think it would be smart to have
this
second hose sensor only allowed to be activated if the gate is
actually
closing. Where would be the correct spot, assuming one exists, to
insert the
second hose sensor that would *only* open the gate if the gate is in
the
process of closing?

Thanks for your reply.


Yipes! All those uninsulated terminals look dangerous to me....

Drawing out schematics of relay equipment is an art in itself. You
have to establish conventions (ie, moving and stationary contact sets,
coil relationships and status of the total mechanism). You must draw
the whole system when it is in a defined state, such as "gate closed",
and then draw the state of each relay and its associated contacts in
this condition, remembering that the moving and stationary contact
springs must also be drawn to reflect the associated relay situation.

For example your notes say that Relay A is shown de-activated but the
schematic is drawn such that its coil IS activated via the limit close
switch (ie. the gate is closed). Also, the schematic shows the timer
relay is activated from GND at C/9-3 (deactivated) via A/8-3
(deactivated) to 24Vac, yet the timer relay contact is shown as being
open.

The schematic also shows the main power switch is ON and the B relay
is activated. I assume those B contacts are supposed to be normally
open when the relay is deactivated, so if this assumption is correct
and the relay is drawn in its activated position, then the contacts
should be drawn with the moving contact at the top being pulled
towards the coil and making contact with the stationary contact. As
drawn the contacts are shown as opening when the coil is activated but
I assume you meant to draw it with the contacts making when the coil
is activated.

Also, where is the motor connected and what voltage supply powers the
motor?

Unless you can clearly define the status and show things as they
really are in that condition, then it is difficult to work out how
things are meant to work.

Having said that, your first effort is to be commended, considering
you probably haven't had to do this sort of thing before.