Capacitor Help - Page 1
Forum section: electronics / beginners

author: burnettm
author_rank: Newbie
timestamp: December 02, 2013, 05:05:35 pm
content: Never mind, we figured it out below. I overlooked a period on a marking.I am refurbishing a old KitchenAid 3-C Mixer which I think was manufactured some time in the 1950s. Upon disassembling it I found a capacitor connected to the motor. Knowing that these things sometimes go bad with time I decided to measure its capacitance. My equipment is rather cheap, all I have to measure capacitance is a (presumably Chinese) Velleman DVM890 multimeter.The capacitor is marked 109 MFD however the multimeter only measures up to 20 uF. I decided to try it anyways and it measured 160 nF. Is it safe to assume this capacitor has gone bad? Or did it give a false reading because the meter is incapable of going that high?If it is bad, does anyone know where I can find a replacement? I checked Mouser, they only had 1 similar part but it is far too large, an cylindrical aluminum electrolytic measuring 1.8 inches in diameter by 3.4 inches tall, the Mouser part was 539-PSU10835A. The old capacitor is rectangular measuring 1 inch by 1 inch by 0.4 inches. I am not sure if used the right search, I selected 105 - 115 uF for the capacitance and 220/230/250/275 VAC for the voltage.The capacitor is marked:MC-968-E109 MFD220 VACGASCORNELL-DUBILIERThanks!

author: KJDS
author_rank: Super Contributor
timestamp: December 02, 2013, 05:31:58 pm
content: Have a look for motor start capacitor or motor run capacitor.The value of these really isn't critical, just find something that will fit and it's likely to work.

author: madires
author_rank: Super Contributor
timestamp: December 02, 2013, 06:20:52 pm
content: Based on the shape and size I'd assume it's a filter cap, a film capacitor. A motor start or run cap would be just about a few µF (<10). 109MFD stikes me odd.

author: olsenn
author_rank: Frequent Contributor
timestamp: December 02, 2013, 06:24:10 pm
content: I'm assuming the "109 MFD" marking means 1nF, and 220VAC would be the intended (or max) voltage to put across it.

author: madires
author_rank: Super Contributor
timestamp: December 02, 2013, 06:32:39 pm
content: Quote from: olsenn on December 02, 2013, 06:24:10 pmAFAIK old caps are marked with MFD (microfarads = µF) or MMFD (micromicrofarads = pF). But 109 MFD would mean 10^9 µF since 109µF doesn't make much sense either

author: fluxcapacitor
author_rank: Frequent Contributor
timestamp: December 02, 2013, 06:40:25 pm
content: Heres a discussion on antique radio forum, talking about the same/similar capacitor, also from an old mixer .http://www.antiqueradios.com/forums/viewtopic.php?f=2&t=219721&view=previous

author: burnettm
author_rank: Newbie
timestamp: December 02, 2013, 07:00:22 pm
content: fluxcapacitor, thanks a lot! Apparently I overlooked the period which is rather important when determining the value. I guess it is still good then.

author: madires
author_rank: Super Contributor
timestamp: December 02, 2013, 07:00:45 pm
content: Ok, so it seems to be .109MFD. 109nF?

author: burnettm
author_rank: Newbie
timestamp: December 02, 2013, 07:07:20 pm
content: Yes. It is marked .109 MFD, which should be 109nF. I'm guessing a combination of the tolerances on the capacitor, the leads coming out of it, and the cheap meter is why it is reading 160nF.