View Full Version : Timer Operation
08-17-2001, 04:47 PM
The timer you have is a fairly standard component. It can be used for either delay on or delay off operation depending on how it is wired.
Before power is applied to pins 2 and 7, the normally open contacts (1-3 and 8-6) will be open and the normally closed contacts (1-4 and 8-5) will be closed. When power is applied to pins 2 and 7 after the delay time then the above situation will reverse.
If you can provide a more detailed description of what you are trying to do, perhaps I can help with a specific circuit diagram. Is there an existing circuit it will be added to?
10-01-2004, 06:45 PM
I just picked up a couple of Omron H3BA-8 timers today and I couldn't find any specs on operation (online). I know how to set the Sec, Min, Hrs and 10hr mode and the time range. What I need to know, looking at the diagram, is whether the timer can be wired to TURN OFF after the set time.
There's normally closed and normally open contacts but when are they NO/NC? Power applied, timer running or power off? Also, how long do they stay in that state?
10-01-2004, 07:45 PM
Looks to be a on-delay timer.. saying that because of no, seperate source, no seperate acutation contacts.
Got a 8 pin base? hook it up and play with it..
that is the easiest way.. Power on 1, Contacts on 3, 4.. Or for a blind guy like me, notch down on relay, bottom outer two are power in, inner two are commons, upper two, Outer is NO, inner two are NC.
IF it is a on-delay, contacts stay in state, after time out period they transfer..
I can make you a off delay, capacitor, resistor and diode...by playing with capacitor values you can vary delay.. resistor keeps diode from blowing when turned on.. (sees it as a short)
(Are we modifying a welder?) I got two dozen small pneumatic cylinders.. if ya need one..
Foot switch, air cyl Pressure, wait for time out (builds pressure), apply current, time out current, off current. Lift foot and pressure dissipates, opens jaws..
10-01-2004, 07:48 PM
I remember a dual knob, omron cycle timer.. I did have a few.
That is what I have been looking for my welder I just bought.. One timer, one cube solid state relay, one solonoid. Simplicity.
Has to be in hundredths of second.. up to 3?
10-01-2004, 07:52 PM
It's an on-delay timer. With power off the NC contacts are closed and the NO contacts are open. When power is applied, it starts timing. If power is removed before the set time is reached, nothing happens. When the set time is reached the NC contacts open and the NO close and it stays that way until power is removed. When power is removed the contacts revert to the power-off state.
What you want is an off-delay timer. They ordinarily have separate power and control inputs and come in an 11-pin package.
10-01-2004, 08:05 PM
I just went to the www.omron.com (http://www.omron.com) site I looked at timers in both on-delay and off delay in same 8 pin package..
So.. Hook it up and play with it.. Use short time settings.. by turning on and off power you should be able to cycle it.
(the omron site hung my computer up.. I have to reboot()
10-01-2004, 08:33 PM
Yea, I been there and a few other sites. The H3BA has been discontinued. I have the sockets too. These have two small (allen or screwdriver) dials and the large time-set dial.
The bottom left changes the time range, the bottom right changes the sec, min, hr and 10hr period. The big dial sets the timer. The pic shows the timer setup for seconds and the range from .0 to 5 seconds.
Found a couple of relays (3-line, 30A) and what appears to be a solenoid contactor (3-line) in the box too. Total cost... 25 cents. http://bbs.homeshopmachinist.net//biggrin.gif
I already have the air cylinder and control pedal.
10-01-2004, 10:06 PM
Up front, it appears like a cycle timer I put in a yarn machine a year or so back.
Apply power, it cycles, times out, motor quits running makes contacts. Release power it recycles/resets.. If so, that is perfect..
You still need a delay on the bottom to wait on air pressure to accumulate to consistient pressure. And then start the cycle timer.
10-01-2004, 10:49 PM
I think this one is the one I want. Trying to figure out how to one-shot it without another relay..
[This message has been edited by ibewgypsie (edited 10-01-2004).]
10-01-2004, 11:47 PM
I was thinking along the lines of having a switch ON the air cylinder (linkage). Since clamping pressure will be a function of air pressure, full extension (or retraction if you're pulling) would trigger the timer.
On second thought, that wouldn't be a good idea. I've often clamped down and had to release for repositioning. Maybe have the pedal on a spring loaded rocker to switch power to timer. Press on the pedal to clamp down then press harder (rocker) to activate the timer.
[This message has been edited by CCWKen (edited 10-02-2004).]
10-02-2004, 08:58 AM
About the only way to get out of the "first timer" is a pressure spring w/switch under it on a moveable cylinder mount. When spring compresses pressure is made.
I was thinking along the line of a time delay, giving the cylinder time to pressurize tongs, then when timing out, a second time delay firing the relay cube through the nc contacts. Then when it times out, power off,nothing more. Lift foot and power removed.
The cycle timer I posted will not work. It is a repeat timer. Unless you had some way of interupting the cycle. (red light and lift foot?)
I was looking for simplicity. If I could find a single shot cycle timer it'd work and cut components down. (simpler is better)
OHH, I envisioned it working by a electrical foot pedal, clamping and all automatic.. If you don't want the complication you just need one timer.
Step on pedal, one process, clamp, weld. Release step on pedal clamp weld. Spot spot spot.. Keep your mind on putting them spots the same distance.
[This message has been edited by ibewgypsie (edited 10-02-2004).]
10-02-2004, 09:24 AM
Now, I have came across 3 transformers suitable for spot welding supplies. Ratio of 16x1 w/#6 coming out of secondary. Pretty darn heavy thou. (about seventy pounds each) Source? A hyster battery charger 3 phase, 3 seperate xfrmers.
And then he said, hey what cha going to do with "that" copper.. I sure could use it.. hey.. how about giving it to me.. I sure could use it.. hey.. (alcoholic friend who sells copper) He got my reactor transformers out of the bridgeport..
I gave him two lottery tickets I had hit the mega ball only on.. he went away happy, thoughts of thunderbird..
10-02-2004, 06:42 PM
The only problem with the "battery charger" transformers is that they don't have the amps. 16:1 ends up pretty weak for a spot welder unless you're working with 30ga. or the like. 30A in is only 480A out. You need 1200A out just to be on par with the HF 220.
I just got through using one of my HF 220's to spot weld 16ga SS to 3/16" thick tube. I wasn't sure it would do it but DANG it did! Had to crank the time up to 4 seconds though.
The spot welder secondary is just under ONE TURN of 1/8x2" copper.