Intermatic time clock problem

[wst01]

I installed an intermatic ET70115C time clock with some HID lights on one of the circuits. The timeclock enabled ok but when the contactor was supposed to release and turn the lights off it did not.Once the HID circut was taken off the time clock it worked fine.
Any ideas on why this may have happened?

 

[davidbeach]

Sun spots. ;-)

Seriously, there is not nearly enough information to even begin to speculate. How were the lights controlled before the time clock, how did the time clock control the lights, how do you know it didn't work, what does it mean that it didn't work, etc., etc.

 

[itsmoked]

You left out: Did it ever work?

Latching contactor land. If the OPEN signal/command didn't work then the lights don't go off...

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[wst01]

Yes, the time clock did operate,and the contactor pull in with the first on comand but the contactor did not release when . The lights were previously operated by a switch.THe switch has now been taken out of the circuit,and the wires connected.I'm not too sure if this extra info is any help but this was an issue a co worker had who is not at the same site as me.

 

[davidbeach]

Electrically held contactor? Mechanically held contactor? What type of switch? Two wire control or three wire control?

 

[IRstuff]

What are the current ratings of the contacts on the time clock? It's possible there's too much current and the contacts get welded together

TTFN

 

[jraef]

Lack of details promotes guessing, so I'll guess that it is a mechanically latched lighting contactor.

wst01,
This means that your contactor would have TWO coils. You would pulse one to pull the contacts in, then pulse the other to drop them out. This is done on a lot of lighting circuits because they don't want the buzzing sound of an electrically held contactor that is held closed for hours, days or even months at a time. One quick way to tell would be if your old switch had a center position, you would flip the switch up to turn the lights on, then down to turn them off, but it would spring return to a neutral center position; either that or it was a set of momentary push buttons, push-on / push-off or something else non-ordinary.

If it is not a latching contactor, then another possibility is that when installing the necessary circuit for the time clock control, someone routed the control circuit wires in the same conduit or raceway as the power wires for the lighting. When you energize the lighting power circuit it creates a voltage on the control wires through inductive coupling from the magnetic fields surrounding the power wires. This voltage could be enough to not allow the coil to drop out when you open the circuit coming from the time clock. Typically it is difficult to induce enough voltage to do this, but if you have a very long run of control wire back through the same conduits, as is sometimes the case with lighting, it is remotely possible.

Go look at the contactor and start there. If you aren't sure, post the part number of it, someone here will be able to tell.

JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> faq731-376

 

[DowntownENG]

Ok here is the deal, these HID lights were on a standard switch, when the lights were taken off the switch the time clock worked like it should. When the lights were put back on the switch the contactor pulled in and never released. The contactor is shot.

 

[IRstuff]

Your phrasing implies that connecting the light to the time cause the timer itself to stop working? or just the contactor wasn't working? Is the contactor now permanently shorted?

Again, what was the current rating of the light? According to the datasheet the ET70115C is rated for 20 A per pole.

TTFN

 

[rbulsara]

You will get much better help hiring a good electrician.

 

[itsmoked]

You need an electrician..

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[wst01]

The sad thing is an electrician installed the time clock....

 

[jraef]

Ok here is the deal, these HID lights were on a standard switch, when the lights were taken off the switch the time clock worked like it should. When the lights were put back on the switch the contactor pulled in and never released. The contactor is shot.

I'm confused here. wst01 / DowntownENG?
Do you have 2 handles, or do you both work at the same place? Or is this response from DowntownENG another guess at the problem?

JRaef.com
"Engineers like to solve problems. If there are no problems handily available, they will create their own problems." Scott Adams
For the best use of Eng-Tips, please click here -> faq731-376

 

[waross]

The list of possible causes boggles the mind.
Possibly itsmoked's suggestions, latching contactor AND get a good electrician.
Possibly the voltage supplied by the time switch circuit did not match the voltage of the contactor.
Possibly jraef's suggestion concerning induction. This could also cause the contactor coil to burnout.
Possibly a control voltage source from the contactor was interconnected with a voltage source from other lights. This could possibly put a lighting contactor in series with another lighting load.
wst01/DowntownENG; do you know if the contactor is/was a latching contactor. Do you understand what a latching contactor is?
What is the make and model of the contactor?
yours

 

[DowntownENG]

I will get some more information on the contactor and post, I am the co worker.

 

[rbulsara]

Get a "good" electrician, ask if he/she has done similar work..It's not that hard.