Capacitor marking - Page 1
Forum section: electronics / beginners

author: TheBrick
author_rank: Regular Contributor
timestamp: February 23, 2014, 09:13:02 pm
content: Hi,I've got a old electrolytic capacitor that need replacing. It is marked at 1000Mf, now I can't believe that it is 10^6 farad so I've guessing it is really 1000 muf. Are some capacitors marked like this?For reference it is approximately 21 mm in diameter and labelled west Germany, so its obviously quite old, so maybe its was a limitation on the marking availability was restricted to ASCII characters only?

author: tszaboo
author_rank: Super Contributor
timestamp: February 23, 2014, 10:47:44 pm
content: 1000 micro farad or 1 milli farad. Muf means something else, particularly female body parts in some countries.

author: hikariuk
author_rank: Unknown
timestamp: February 24, 2014, 05:17:00 am
content: Quote from: NANDBlog on February 23, 2014, 10:47:44 pmIt also refers to a hand warmer worn by women (both are actually spelt muff).

author: Weez
author_rank: Contributor
timestamp: February 24, 2014, 05:42:47 am
content: Quote from: hikariuk on February 24, 2014, 05:17:00 am+1. I've spelted my share of muffs.

author: cybermaus
author_rank: Frequent Contributor
timestamp: February 24, 2014, 06:06:19 am
content: Quote from: TheBrick on February 23, 2014, 09:13:02 pm21mm diameter and what length? And what voltage? What application? The latter is important to 'Guess' the size and its most likely order of magnitude. Though I would agree 1000uF is most likely.If you search the net, you will find some 1000uF/1000MF links, hinting that some people think it is the same thing . But if it ever was printed like that on actual devices? As you probably know, the lowercase letter u is more common in the ASCII era.

author: TheBrick
author_rank: Regular Contributor
timestamp: February 24, 2014, 07:32:35 am
content: Thanks for the reply.Sorry about the vagueness, its approximately 39 mm long, 63 volts on a control board for the motor and contractor on a mig welder. I have not fully traced out the board so specifically what it does I'm not sure. The board does take an 24 or 36 V AC (can't remember which right now) power input. The motor is DC, so I'm guessing its a smooth cap of some sort. Its the biggest on the board.Of course you're right u is going to me the more likely to replace mu in ASCII.

author: cybermaus
author_rank: Frequent Contributor
timestamp: February 24, 2014, 07:57:19 am
content: Well, nowadays 1000uF 63 volt seem to be between 14x25 and 16x30.I guess old paper based ones may indeed be 21x39I would just assume and try 1000uFWe can safely assume it is not going to be 1000 MegaFaradAnd even 1000 milliFarad is unlikely.Though search as I might, I can find text references to MF and Mf, but no photo's of actual device markings like that.Maybe you can post a photo?

author: G7PSK
author_rank: Super Contributor
timestamp: February 24, 2014, 09:27:24 am
content: What make of MIG. welder. Is it single or three phase, most single phase units have a capacitor or two for arc stability. Good makes have a whole bank of capacitors.

author: TheBrick
author_rank: Regular Contributor
timestamp: February 24, 2014, 07:24:07 pm
content: Here is a photo attached.@G7PSK Its a migatronic, I think they are Danish from memory. Single phase 180A. Its not the main capacitor bank after the rectifier. Is that what you are referring to? Its on the motor control board.

author: SeanB
author_rank: Super Contributor
timestamp: February 24, 2014, 08:13:22 pm
content: 1000uF 63Vaxial electrolytic. It really should have been marked 1000mmF, but they often dropped the second m. Best is to replace with a 1000uF 100V 105C unit, it will be closer in size to the original. you might find it hard to get an axial unit though, so get the radial one and extend the one leg with a short wire, bend it using needle nose pliers to keep from damaging the end seal and sleeve it till it reaches the other hole. Glue the capacitor down with a blob of flexible 2 part epoxy ( Pattex Pliobond or equivalent) or acetoxy free silicone ( the non vinegar smelling one) for application to copper or electronics and it will be fine.

author: TheBrick
author_rank: Regular Contributor
timestamp: February 25, 2014, 06:50:47 pm
content: Thanks for the tip regarding 105C unit. I have noticed axial caps are harder to find. I suspected as much that it was some odd marking but wanted the opinion of some more experienced eyes. Thanks for the help. I just hope this solve the problem!

author: cs.dk
author_rank: Unknown
timestamp: February 26, 2014, 05:28:43 pm
content: Hi,Hope that you can sort the problems out..If needed, send me a PM - I know some people at the factory and service-team. And yes, it is a Danish company, well known for quality machines, got 4 my self.. Maybe we can get a circiut-diagram, and they often know what is wrong, when "it does not do that, and that"

author: dentaku
author_rank: Frequent Contributor
timestamp: February 26, 2014, 11:55:05 pm
content: I've got a bin of ancient caps labeled MFD all in capitals like that.The first time I saw it I found it strange too. Some are waxed and others are hard molded plastic cases.Most are just .0022MFD and tiny amounts like that but they're up to 600V.

author: cybermaus
author_rank: Frequent Contributor
timestamp: February 27, 2014, 05:45:23 am
content: But with values like .0022MF it may actually be even more confusing. Unlike a 1000MF capacitor, with .0022MF could stand for both milli and micro (Making it 2.2uF or 2.2nF respectively) You'd have to go on physical size. (if they were broken so you could not simply measure them)The photo made me remember: I actually trew out a small lot of very similar looking axial caps last year, figuring that after 30 years in a box, they would no longer be good, and even if they were good, better smaller ones would exists so I would not ever use them. Now I wish I still had them if only to check the labeling.

author: TheBrick
author_rank: Regular Contributor
timestamp: February 27, 2014, 09:16:13 pm
content: Quote from: cs.dk on February 26, 2014, 05:28:43 pmThanks for the off cd.dk. I'll give this a go and it does not work I may shoot you a message.