Sat Oct 26, 2013 5:31 pm
I've thought about your test using a voltmeter and now I think it's a good test method if you don't have a old analog meter with a sensitive current scale. I initially didn't like it because I've never seen anyone do it, but I come from where we always had many pieces of test equipment available, if we wanted to measure current we used a ammeter. I use a Simpson 260 which has a 50 micro-amp scale which is very sensitive. I'm not sure how a DVM would do in this mode since the input impedance is so great. And in your method, you don't know how much current is leaking by reading the voltage scale but you can say there is "some leakage". So I apologize for my earlier post, I have thought about it and think it's good to determine if there is leakage.
Sat Oct 26, 2013 5:58 pm
In the early days of sold state electronics, some of the existing test equipment used more power from the circuit being tested than did the solid state components in the circuit being tested. That resulted in many erroneous test results. Thus the prized Simpson unit,and others, with significant sensitivity was developed and is valuable for that use. I built a Heathkit VTVM a bit before that era.
Generally, I just use the simplest test equipment at the start and then move to more sophisticated units if the situation requires.
As far as I know, the test I proposed is the most sensitive test possible with the least sophisticated equipment extant. Other, different, additional, tests are possible and may be indicated.
Sat Oct 26, 2013 8:39 pm
Bus driver, had to look that one up! Very satisfactory indeed.
Fri Nov 01, 2013 1:08 pm
For those wanting a low cost meter for testing, the link below is about as good as it gets these days. Fabricating a housing plus supplying leads and clips will be necessary. For the price, the unit looks to be really good quality.
I bought a similar ammeter as a replacement on a portable battery charger where the original ammeter had gotten smashed. Mounting it in the charger was a bit of a challenge but the results were quite good. http://www.ebay.com/itm/0-20V-DC-85C1-A ... 45fe89c5fb
Fri Nov 01, 2013 4:09 pm
For an extra $.99, I'd recommend this meter at Harbor Freight.
You do not have the required permissions to view the files attached to this post.
Fri Nov 01, 2013 4:46 pm
I'm on my 2nd meter recommended by Gerry, above. I think the batteries died in the first one after 4 or 5 years. Cheaper to throw away then to install new batteries. This meter is great for shop use and as accurate as the much more expensive meters owned by my son and myself.
Fri Nov 01, 2013 6:11 pm
Bus driver, I have a simular voltmeter. Think it came from Radio Shack. Took some lamp cord/speaker wire and hooked it to a cig. Lighter/ power port plug. Plugged In to port to monitor voltage in vehicles with only amp gauge.
Fri Nov 01, 2013 6:53 pm
I have 3 of those from Harbor Freight. Occasionally they are free with coupon and purchase of another item. They are useful for some tests, including Ohms.
For Cubs, the test methods I use rarely require more than the analog voltmeter and the Ohms function of some other tester.
Your mileage may vary.
Fri Nov 01, 2013 7:20 pm
Why not use one inexpensive meter that will do everything you need? And you can throw it in your toolbox.
Fri Nov 01, 2013 7:35 pm
ibrake4rust wrote:Why not use one inexpensive meter that will do everything you need? And you can throw it in your toolbox. Gerry
Or have an OH CHIT moment when you find out you have left the meter in a position to be destroyed. Hasn't happened yet with a multimeter just a fairly expensive gift watch, that got run over by a very big machine.
Must have been someone elles fault. I took off the watch and put it in my pocket to keep it safe.
Fri Nov 01, 2013 8:10 pm
ibrake4rust wrote:Why not use one inexpensive meter that will do everything you need? And you can throw it in your toolbox.
Having made my living my entire life as an electronics technician, I have learned to NEVER rely on only one meter. they will quit at the most inopportune time, and there is nothing more frustrating than having a piece of test equipment go bad when you need it, and not have a spare..
Fri Nov 01, 2013 8:11 pm
Bus Driver recomended an analog vom. I have an old one that still works but needs new leads. Got it when they were about $7 on sale. Don't know if they still have them. Also have a Greenlee digital that much smarter than I am, lol.
Sat Nov 02, 2013 6:29 am
Yeah, I have one of those smarter than me too!!
Fri Dec 13, 2013 1:03 pm
had both my Super A and the B painted with hitatchi alternators on them ,to blend them in better. On the A/B/C series tractors, the generator sits on the side of the block, not under the hood.
anyway, I started making up the wiring harnesses, which was fine for the Super A with battery ignition, but the B has a mag. that leaves no switchable place (with the standard mag grounding switch)to attach the exciter lead for the alternator. and if you leave it connected hot, there's enough of a current draw to kill the battery.
Solution: remove the 3 wire Hitatchi alternator, and install a NAPA S10 one wire. Boss Hog will be smiling!
Fri Dec 13, 2013 5:41 pm
For the magneto tractors, a couple of other solutions exist. One would be to use a double-throw switch for the magneto kill. Might be difficult to find such a switch that looks like the original. With double-throw, the contacts grounding the magneto primary open (engine Run position) and the contacts for exciting the alternator close. Moving the switch to the other position closes the contacts to ground the magneto ( stop) and opens the contacts to the alternator.
The other solution is to use an oil pressure switch that closes on pressure rise. So the alternator would be excited only when the engine has oil pressure.
Powered by phpBB © phpBB Group.
phpBB Mobile / SEO by Artodia.