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Forum section: electronics / repair

author: scnj
author_rank: Newbie
timestamp: June 30, 2023, 08:53:21 pm
content: Hello, I'm hoping that this is the right forum to post this type of question!Here is the problem: I have a large format printer that has a built in chiller. A few days ago we smelled a slight burning smell coming from the machine. We could not pinpoint the issue so we let it continue to run. The next day as it was running we saw a spark from the machine and then smoke. After shutting everything down and opening it up, we found this. (see photos)Although it just looks like a Current limiter got fried, the service tech came and informed me that they are only able to replace the entire chiller as the electronics are housed inside the chiller unit. Cost is $17k!!After getting past the initial shock, I let the service tech leave and I took apart the chiller unit and found the parts that were burnt. It looks like the inrush current limiter blew as you can see in the photos, it also burnt up the Contactor next to it.I ordered replacement parts for the three rail mounted terminal blocks, (2) inrush current limiters, and Contactor din/panel. Basically everything close to where the blown part was located.My question is, what would have caused this? Should just replacing the parts in question be enough to fix this? Could it just be that the inrush current limiter failed due to age? The printer is in high use every day. I'm hoping that this is the case. But I thought I'd post here to see how the experts weight in and if you would do anything else differently.Any input is greatly appreciated!

author: Shonky
author_rank: Frequent Contributor
timestamp: June 30, 2023, 10:22:00 pm
content: The only parts likely to really need replacing are the inrush limiters. The contactor and terminal block are likely fine. Just clean the black carbon etc off them (also the module on the right)How much current does the unit usually draw? Perhaps parts are just close to limit. Does the device get frequently powered off and on?I'd just replace the two inrush limiters, clean up the rest and go again. If it works fine from there, get some spares and/or look at perhaps getting some higher rated parts?

author: srb1954
author_rank: Super Contributor
timestamp: June 30, 2023, 11:44:46 pm
content: I would replace the terminal block as well. It looks like it has partially melted where the leads of the left-hand inrush limiter enter the block.The inrush limiters normally run quite hot so, if you have room, I would move the assembly a little further away from the contactor to prevent long term thermal damage to that device.It also looks like there is one of the dreaded RIFA capacitors peeking into the bottom of the second photo. Carefully inspect the case of this capacitor for cracks or crazing of the epoxy encapsulation. If any evidence of this is found then replace the capacitor immediately, preferably with a different brand. When these RIFA capacitors fail, which is almost a 100% certainty, they will emit copious quantities of the magic smoke and a terrible stench that hangs around for days.

author: scnj
author_rank: Newbie
timestamp: July 10, 2023, 01:23:43 pm
content: Thank you for the quick help! I just received the contactor/dinpanel but the model number has an extra character in it.I though I ordered the exact same one, DIL M9-10 but this one says DIL M9-10-PIThey both show 230v 50/60hz but the new one does not have the openings on the side for the the wires. Instead it looks to be two smaller holes on top to accept the wiring. Will this work or should look for the exact same part? All of the numbers on the side seem to match up.

author: Shonky
author_rank: Frequent Contributor
timestamp: July 11, 2023, 03:02:51 am
content: Yeah so you definitely would want to replace that based on the most recent pictsAs a contactor it will probably work just fine - more just depends if the existing wiring works as is or you need to modify it as well. I'd probably try and get the right part.Did you order the wrong one or they sent you the wrong one?

author: Mario87
author_rank: Frequent Contributor
timestamp: July 11, 2023, 02:11:15 pm
content: Appears to be an NTC (Negative Thermal Coefficient) inrush current limiter...these by their very nature run hot, the hotter they run the lower their resistance.The datasheet even says the following:Body Temperature at 100% Max Current: 214.00 °c(max current = 15A)My bet is just old age and the constant high running temps if the printer is used a lot and under a lot of load.

author: scnj
author_rank: Newbie
timestamp: July 14, 2023, 03:13:39 pm
content: Just wanted to report back and thank everyone who commented. I was able to get the wires connected to the new Contactor. Everything is back up and running. Crisis averted. Thank you everyone for helping out!

author: DonKu
author_rank: Regular Contributor
timestamp: July 14, 2023, 03:50:04 pm
content: Inflation drove up the price of couple of NTC thermistors to $17,000.00? I hope you gave yourself a hefty bonus.

author: tooki
author_rank: Super Contributor
timestamp: July 14, 2023, 11:06:03 pm
content: Quote from: scnj on July 10, 2023, 01:23:43 pmThe -PI suffix means “push-in”, i.e. the spring-loaded terminals instead of screw terminals. So you simply ordered a variant with different terminals, otherwise identical. (And IMHO you got the better choice.)

author: tooki
author_rank: Super Contributor
timestamp: July 14, 2023, 11:29:29 pm
content: Quote from: Shonky on July 11, 2023, 03:02:51 amBased on the Farnell part number on the box visible in the photo, they ordered the -PI version.