Machine issue -elusive !

[MIOMY]

Good day good people of the Injection Moulding world. I have an elusive "short circuit on thermocouple" alarm that pops up whenever it feels like it...sometimes frequent...sometimes a couple times a shift. It interupts the cycle which becomes very annoying when trying to accomplish other tasks of the day. This occurs more frequently on our 450 and 650 ton Kawaguchiis. Just toggle the cycle switch to off and back to cycle the alarm clears and off we go...I am setup/process tech and have an understanding of the entire machine function but electrical being my weak point and our 1 maintenance man is busy with other priority jobs. He tells me he believes there is low voltage in the plant to certain machines...but why would it show same alarm on different machines...possible I guess but I would have thought other problems would arise other than a silly thermocouple alarm...Thank you in advance for any info or insight to this issue.

Play safe...if it can happen it will !

[Suhas]

Hi MioMy,
Welcome to the forum!
What do the people from the machine manufacturer say? Is it the same zone on every machine?
Suhas

[brentb]

Have you calibrated the TC?
Is it a "J" or "K" TC? I can't remember which the Kawas use, but you must use the correct one.
Is it a late 80's to early 90's Kawa?
Is it a grounded or ungrounded TC?
Have you tried grounded if it is ungrounded or vice versa?
Are you sure it is a TC and not an RTD?
Swap TC's with a zone that woks and see if fault follows TC
Also, you can no longer go by Red/yellow= K or White/red= J color coding to ID the type TC, as those only applied in USA


Keep on Molding!

brent

[rickbatey]

I too suspect stray voltage or maybe even static causing the issue. If that fails then double check the type of t/c's used.
With the short circuit alarm, I wonder if this happens because the machine applies heat but the t/c is slow or fails to show a heat rise?!
Rick.

[MIOMY]

It doesn't specify any zone at all...just an error code...i will be looking into this more today. Thank you for your reply.

[MIOMY]

Yes the machines are around that age...I will have a closer look of your mentionings and respond. Thanks very much Brent.