How much watt does this resistor have? - Page 1
Forum section: electronics / beginners

author: mortos360
author_rank: Regular Contributor
timestamp: June 26, 2014, 05:55:51 pm
content: I found similar images to this and they seem to be 5W wire wound resistors, but I can't find the exact model online... maybe some1 can tell by experience?!Thanks!!

author: jlmoon
author_rank: Unknown
timestamp: June 26, 2014, 06:06:14 pm
content: that would be a 5 Watt sand filled resistor in a input limiting function on a SMPS or could be in a audio application. Some refer to them as Cement resistors, they are used in power applications and possess reasonable temperature stability along with excellent fire retardant characteristics.http://www.mouser.com/catalog/specsheets/XC-600041.pdf

author: rob77
author_rank: Super Contributor
timestamp: June 26, 2014, 06:08:58 pm
content: it's definitely not rated for more than 5W of power dissipation. if that connector next to it is a 2.54mm pitch then i would guess even less than 5.and BTW... resistors don't have watts

author: jlmoon
author_rank: Unknown
timestamp: June 26, 2014, 06:13:58 pm
content: yeah Rob, but they sure have a lot of hidden smoke lurking inside..

author: Neilm
author_rank: Super Contributor
timestamp: June 26, 2014, 06:44:19 pm
content: I have seen that package which thermal protection. IIRC it was a 5W device used to charge up the main caps on a 300W mains SMPS. The thermal protection kicked in in the event of an overload. I don't remember if it was a one shot device or not.

author: RazSlack
author_rank: Contributor
timestamp: June 26, 2014, 07:18:27 pm
content: Hey-hey! Lookie what I found:http://www.uchihashi.co.jp/korea/image/y5ja.pdfLooks similar?

author: jlmoon
author_rank: Unknown
timestamp: June 26, 2014, 07:28:25 pm
content: exactly... thats a poor mans .. Surgistor.. , IIRC I believe Tektronix used similar technology on the input to the bridge rectifiers in some of their power supplies to ease the input current during cold startup when the input caps first look like a short to those diodes.

author: mortos360
author_rank: Regular Contributor
timestamp: June 26, 2014, 07:41:23 pm
content: Quote from: RazSlack on June 26, 2014, 07:18:27 pmRespect!!!I spend almost an hour on google without any success...Anyway... can I replace it with just a 5w 10r resistor or would that be too dangerous?Thing is.. I can get a 5w resistor easy around here... this thermal cutoff/resistor thing is probably something I have to order online where ill probably pay more for the shipping then for the part itself.

author: jlmoon
author_rank: Unknown
timestamp: June 26, 2014, 07:46:48 pm
content: I think you could order that from MCM electronics.. or some of the audio parts suppliersbest would be to go back to manufacturer of the device it is in.Correction: .. MCM does not have.. but ....http://www.cci-tco.com/elcut-a5mc-series-rohsthey do!!

author: Neilm
author_rank: Super Contributor
timestamp: June 26, 2014, 08:58:26 pm
content: Quote from: RazSlack on June 26, 2014, 07:18:27 pmThat looks like the thing I remember.Quote from: mortos360 on June 26, 2014, 07:41:23 pmI do know that when we replaced it with an ordinary resistor we had issues with reliability. The resistor worked for a while then died - even though it should have met all the requirements for the rating. We ended with a posistor in there instead

author: cellularmitosis
author_rank: Unknown
timestamp: June 26, 2014, 10:19:38 pm
content: Quote from: rob77 on June 26, 2014, 06:08:58 pmTrue, mortos360, the question is "how many watts can it handle / survive?"

author: beretmaster
author_rank: Newbie
timestamp: June 28, 2014, 12:35:57 am
content: You never really know until it pops...

author: wraper
author_rank: Unknown
timestamp: June 28, 2014, 11:04:04 am
content: Quote from: RazSlack on June 26, 2014, 07:18:27 pmActually I would not be so sure. There is no any temperature rating on the package while it is present on all thermal cutoff devices from this manufacturer on their website. I would say that this is just simple 5W resistor from the same manufacturer, yet there are no any mentioning of simple resistors on their website.

author: wraper
author_rank: Unknown
timestamp: June 28, 2014, 11:10:16 am
content: Description of the Y5JA Series:It is a high performance thermal cutoff/ resistor assembly which combine two coil-winding resistors with a fusible alloy type thermal cutoff and has an overheat protect function.It realizes reducing the mounting space and decreasing the number of components.It uses a coil-winding for greater ability to withstand inrush current.It will open the circuit certainly in the case of any circuit malfunction. Its characteristics will rarely fluctuate.It provides extremely robust electrical insulation and voltage withstanding properties after it functioned, and almost no trouble occurs with residual resistance or re-continuity.Because the marking is printed on the topside, it is easy to confirm the products after assembling.And there obviously is not any marking present on top.Edit:Actually there is a hint in the Y5JA datasheet.They compare it with R5B series ceramic resistor. So obviously this is just simple resistor.

author: mij59
author_rank: Frequent Contributor
timestamp: June 28, 2014, 11:24:30 am
content: Quote from: mortos360 on June 26, 2014, 07:41:23 pmIts a safety feature, do not defeat it.For testing you could use a resistor.Why did the resistor pop ?

author: EEVblog
author_rank: Unknown
timestamp: June 28, 2014, 12:20:36 pm
content: Quote from: mij59 on June 28, 2014, 11:24:30 amYes, I'd be concerned as to why a 5W cermet power resistor failed...

author: SeanB
author_rank: Super Contributor
timestamp: June 28, 2014, 12:34:42 pm
content: They often fail from repeated switching surges, or from mains noise that was clamped by a varistor placed after the resistor, or from high frequency noise that was absorbed by the mains filter. Generally they are designed to fail with a surge overload of a few seconds, so they operate safely and do not heat up to cause a fire hazard.

author: mortos360
author_rank: Regular Contributor
timestamp: June 30, 2014, 01:58:50 pm
content: Quote from: mij59 on June 28, 2014, 11:24:30 am1 of my test hooks made a short to the chassis and discharged the caps from the second board.From what I can tell, the resistor and the fuse in front of it was the only parts that got damaged... but I will know for sure once I replace that resistor.Thanks for all your feedback people!!

author: ProBang2
author_rank: Frequent Contributor
timestamp: June 30, 2014, 02:22:56 pm
content: Quote from: rob77 on June 26, 2014, 06:08:58 pmand BTW... some resistors havelook at this resistors, especially the one at the right side:http://www.soselectronic.com/a_info/kat2010_eng/a06.pdf