O.T. I need a timer relay

Dear Sirs,
I have an expensive, not very reliable timer relay that I would like to
replace with something cheaper and more reliable.
(The old one is an electro-mechanical monstrosity.)

I think it is going to be a timer off delay. When activated it runs a chain for
seven seconds, then stops. There is a latch relay which latches and holds
for a while, then it is unlatched and the timer starts, runs the chain, then
stops. My problem is a second set of contacts in the timer, which serves to
disable another part of the circuit so the chain contactor will not latch itself in
and the chain keep running.

This (I hope) is what the timing diagram look like . . .

Any hints as to what I might be able to replace it with?
Thanks, Poet.

What are the voltages that your equipment runs at?

Is a PLC already in the system?

If it's relay logic that you're working with, buying a CLICK or inexpensive PLC may be more beneficial.

I am trying to understand your picture and how it relates to the description...

About the ten minute delay: Is that part of the same device?
Same with the latch relay, is it part of the device? And at the end of the 7 second time, it latches and holds for "a while" can you narrow down that to something more specific?

I am not sure if you have one timer, two timers, or three...

Can you share the part number of the failing device?

I have had good luck over the years with Omron. They are available with a variety of coils and in on-delay, off-delay, and repeat cycle models.

Mad_Poet said:

Dear Sirs,
I have an expensive, not very reliable timer relay that I would like to
replace with something cheaper and more reliable.
(The old one is an electro-mechanical monstrosity.)

I think it is going to be a timer off delay. When activated it runs a chain for
seven seconds, then stops. There is a latch relay which latches and holds
for a while, then it is unlatched and the timer starts, runs the chain, then
stops. My problem is a second set of contacts in the timer, which serves to
disable another part of the circuit so the chain contactor will not latch itself in
and the chain keep running.

This (I hope) is what the timing diagram look like . . .

Any hints as to what I might be able to replace it with?
Thanks, Poet.

Click to expand...

I'm having a hard time understanding this time diagram as it seems to be missing the inputs you're using to set the coil. That being said, it should be a fairly straightforward implementation on a PLC system. PM me more details, I'll glady write a few rungs of code which will accomplish exactly what you need?

Does the system have an existing PLC, if so, I'd migrate it to that. If not, I'd probably suggest an inexpensive AB PLC which will allow you to add this functionality & maybe migrate some of your other IO onto it. I use the 1769-L30ER quite regularly for something like this.

Cheers,
Vlad

The old timer is an ATC 3-0322B005A22CS.

There is no PLC in this system (hence the O.T.)

Everything else in the panel gives me virtually no problems. This particular timer
I am having to replace more often than I'd like.

The ten minute delay . . .
Picture a chain drive in the floor of a long room pulling these carts along and around the
room. When an operator needs a cart, he pushes a button and the cart comes off the
main chain and stops when it hits a limit switch. (There is a second chain called a 'spur
chain' which pulls the cart off the main chain.) The ten minutes could be two minutes,
or many hours. But the cart sits there till the operator hits an 'Advance' button. At this
time the latch relay is unlatched and the timer 'coil' goes to zero volts and the TR-2
starts running (which runs the spur chain) - for about seven seconds then it times out and the spur chain stops.

When the advance button is pressed, the TR-2 contact (9-10) sends 120 Vac through some
other circuitry to pull in MS motor starter to drive the spur chain. The other Tr-2 contacts
open up to keep the MS starter auxiliary contacts from latching in so the chain will
stop running when TR-2 times out. (After it times out the other TR-2 contact closes
again so that other circuits can start up the chain next time a cart needs to come off
the track.)

Everything in this box runs at 120 Vac.

I thought a simple off delay timer with two sets of contacts would do it. . . . .
But half the time both contacts would be closed and the chain would keep running . . .
Poet.

Got prints?

It sounds like the load handled by the contact that keeps failing might be the true culprit.

I found the data sheet for that relay here (Download Catalog). It is nothing special really, off delay, 120v coil, has instantaneous and timed contacts. Non-inductive load rating of 10A @ 120v. I bet your load is inductive or surging or just too much...

I would agree with Tom about using a more modern electronic timer but stick some plug in interposing relay in there too to drive the load now being handled by the timer, and use the timer relay contact to operate the coil to this small cheap, easy to swap relay. Then the timer should last forever and if anything keeps failing it would be the little simple relay. If the relay ultimately pulls in a motor starter, it probably needs attention, and a quick and easy way to reduce spiking of a starter coil circuit is to add a surge arrestor to it.

To me this sounds like a good candidate for a smart-relay, or micro-PLC.


A small 4 input, 2 output can be easily programmed to do what you need

Dear Aabeck,
My boss said the same thing yesterday. I think I'll look at the Omron offerings first . . .
Then see about a very small inexpensive PLC.

Okie,
The problem is not the contact points failing. It has a little motor in it that occasionally
fails . . . and a solenoid coil which occasionally fails . . . and a spring and some little
plastic teeth which need to mesh and unmesh . . . and a limit switch assembly with some
little set-screws that I sometimes have to adjust so one contact opens before the
other contact opens . . .

A tiny little PLC cmall enough to fit in the same hole with 120 Vac inputs and outputs is
looking more and more attractive. (And I think I can code such a simple application.)
Poet.

For the more curious : TR-2 is my problem child. With luck, here be the circuit.

Mad_Poet said:

Then see about a very small inexpensive PLC.

Click to expand...

I would use a PLC also... but I have use a lot of Omron programmable timers and they have worked great

The two PLC's I would look at we be the Click from Automation Direct also the LOGO from Siemens

https://www.siemens.com/global/en/home/products/automation/systems/industrial/plc/logo.html

https://www.automationdirect.com/ad...series_plcs_(stackable_micro_brick)/plc_units

If you need to adjust your timer, you can:
a) turn the knob on the timer.
b) break out the laptop to plug into the PLC.
c) include a tiny HMI with your PLC based timer.

If you never need to adjust it, then by all means use a Click with a couple of interposing relays.

OkiePC said:

If you need to adjust your timer, you can:
a) turn the knob on the timer.
b) break out the laptop to plug into the PLC.
c) include a tiny HMI with your PLC based timer.

If you never need to adjust it, then by all means use a Click with a couple of interposing relays.

Click to expand...

Or... you could wire in a potentiometer (0-10vdc) to the Click and have that as your timer span, then you can have the best of both worlds for under 5 bucks

Allen Bradley Micro810 ($85.00) can be setup as a standalone smart relay or a full blown micro PLC.

Aabeck > A small 4 input, 2 output can be easily programmed to do what you need

Mr. Aabeck,
Can you please tell me more about this little dude? Two relay outputs would
work nicely, and if I can make a relay contact do the input (as in PLC provides 24Vdc
to one side of a contact then when it closes make the input).

One of the Micro810's looked good too . . till I looked at how much space it requires.
I have about an 8cm by 8cm spot for it to fit in. And there is another On-delay type
timer both above and below . . . might make the necessary ventilation problematic.

The Click plus power supply is looking like 10cm by 10cm . . . Not gonna fit.

Aaarrrghhh.

Poet.

Mad_Poet said:

The Click plus power supply is looking like 10cm by 10cm . . . Not gonna fit.

Aaarrrghhh.

Click to expand...

Why do you need a power supply, do you have 24vdc in the cabinet ?

OR

https://www.zoro.com/omron-programmable-relay-100-240vac-zen-10c1ar-a-v2/i/G3010061/ and you can have it Monday

http://www.ia.omron.com/products/family/1755/specification.html