Ben Okopnik wrote: > On Tue, Feb 01, 2011 at 07:48:40PM -0500, Ben Okopnik wrote: > >> set your meter >> on a medium resistance setting and touch the leads to the terminals >> (take the bulb away, of course.) Next, reverse the leads and watch the >> meter as you touch them to the terminals: it should spike and then >> slowly come back to a relatively high resistance value. If it doesn't >> spike, or doesn't discharge to a high resistance value, it's bad. >> > > On re-reading, I realized I should give some more details for anyone > who's never done this before. On the first pass, hold the leads on the > terminals for a good 5 seconds or more; you're actually charging the > capacitor from the meter (that's why you need it to be on the resistance > setting, which puts out a little voltage.) If the meter shows a steady > short, or some steady low value during that phase, you've already > diagnosed it: it's shorted. Next, when you reverse the meter, you want > to watch the scale very closely: depending on the value and your meter > setting (higher is better for small cap values), that spike might just > be a very short twitch of the needle. E.g., a 1μF capacitor when tested > with a meter with 100kΩ internal resistance will discharge in ~ .63 * R > * C seconds, or > > .63 * 100e3 * 1e-6 = .063s > > ...less than a tenth of a second. Gotta watch it pretty carefully. > > Fortunately, most AC caps tend to run from 5 to 50μF or so, which is > slow enough that you should even be able to roughly estimate if the cap > value is somewhere near what you want - as long as you know your meter's > internal resistance, that is. > > > Ben > Yep, I've done that before. Been so long I forgot. So I got out the trusty meter and lo and behold it's got a capacitor function. I now have a 1 nF cap. Hm, I looked at the motor and found it said 7.5 uF, 370 V. With luck I'll find one tomorrow.
Thanks I'm fairly certain that's the problem, now where did I put that wool blanket? Jim. _______________________________________________ Liveaboard mailing list [email protected] To adjust your membership settings over the web http://liveaboardonline.com/mailman/listinfo/liveaboard To subscribe send an email to [email protected] To unsubscribe send an email to [email protected] The archives are at http://www.liveaboardonline.com/pipermail/liveaboard/ To search the archives http://www.mail-archive.com/[email protected] The Mailman Users Guide can be found here http://www.gnu.org/software/mailman/mailman-member/index.html
