delay timer probs

[willies boy]

Dairy deck has now had 3 delay timers on over 3 years ,last fitted only week ago ,power to it but not timing out to feed contactor ,anyone ideas as to why its getting through so many?? i switched off condensing unit then back on and it timed out and worked :rolleyes:anyone got a recommended type other than the EBERLE one we are using

[monkey spanners]

IMO do a programable timer, you can set them for delay on, delay off and a few other things also.

[chemi-cool]

Omron and Crouzet are my timers.

I am also building electric boards and never had any complains about them.

http://omron.co.uk/

http://www.edcscotland.co.uk/acatalog/EDC_Products_Electronic_Timers_214.html

[Gingerair]

Firstly check all related connections & that it's sized correctly for your application, or just fit one with the same function but a higher current rating & maybe a different make, as Chemi said Omron/Crouzet are good..

[willies boy]

Thanks guys i thought that the rating was suspect ,but each engineer is ordering the part that he is replacing ,ill get a larger unit,but ..............would it actually matter as its in the control circuit and only pulling in the contactor not carrying full load??

[monkey spanners]

This is what i carry on the van

http://uk.farnell.com/imo-precision-controls/tdma/timer-multifunction/dp/9940391

The last ones i got had no setting instuctions and i had to go online to get them! Check packaging before going to site!

If it is only switching a contactor then the rating should not be a problem, unless there is a short in the wiring or someone has wired fan motors for example into the control circuit. Maybe a test with an amp probe would be worth doing.

[Gingerair]

I would say it does matter, the coil in a contactor is an inductive load. The quality of the switch gear may also be an issue..

One way to find out would be to fit a timer of the same make but with a higher current rating & see how long it lasts...

Ginge :)

[tonyelian]

hi
if ur contactor has an auxillary contacts n/o n/c you can with a special connection cut the power energizing the timer so it lasts long cause its onlly energized during delaying time

[chilliwilly]

Omron and Crouzet are my timers.

I am also building electric boards and never had any complains about them.

http://omron.co.uk/

http://www.edcscotland.co.uk/acatalog/EDC_Products_Electronic_Timers_214.html

Best timers money can buy!

If your timer contactor rating isn't matched to the contactor coils transient spike. Then you could consider using a small relay driven by the timer with 20 amp contacts, to drive the contactor coil. The circuit should last much longer with fewer problems.

That's if tonyelians suggestion about the contactors auxiliaries, aren't included with the contactor.

[Magoo]

The inductive spike of contactor coil will be destroying the PNP/ NPN transistor switch in timer, either go for a timer with actual contacts in it or a mini relay driving the contactor. Snubbers across contactor coil may help.

[willies boy]

Nice replies ill be looking into it ,i knew there was something we were missing

[Magoo]

Hi willies,
let us know how things panned out, good to get a resolve to problems, and feed back.

[coolhibby1875]

i always use crouzet timers, also replace the contactor next time!

[willies boy]

Well i went back and there ws no light on the timer although power to it ,i moved the power wire from where it got its feed from to a leg of 3 phase coming in ,it lit up fired up comp and ive not had any more probs ???why would it make any diff putting it to a mains live coming in ,?

[coltleader]

Dairy deck has now had 3 delay timers on over 3 years ,last fitted only week ago ,power to it but not timing out to feed contactor ,anyone ideas as to why its getting through so many?? i switched off condensing unit then back on and it timed out and worked :rolleyes:anyone got a recommended type other than the EBERLE one we are using

The problem might be that the delay timer (http://www.acdcind.com) contactor rating and the contactor coils transient spike are not matched up correctly. A different circuit should have fewer problems. You might try that.

[willies boy]

Been back to do maintenance at this site and all is now good ,swopping it to another leg of 3 phase cured it :confused: