formariz 11,987 #1 Posted July 21, 2014 I am retrofitting a new engine to one of my round hoods with a starter generator. It's all done and working fine . Tested to see if it's charging properly but was not sure of reading so as a reference I tested my RJ with the same set up. I don't know what the heck is going on but the RJ drives the meter nuts. First I get readings with just the negative probe touching any part of tractor. Then when placing probes correctly on the parts to be tested I get crazy readings with all kinds of rapid fluctuations . Tractor runs fine and charges fine. What could be driving meter nuts like this? Share this post Link to post Share on other sites
Geno 1,929 #2 Posted July 21, 2014 I would start with checking your grounds. Share this post Link to post Share on other sites
formariz 11,987 #3 Posted July 21, 2014 I did since from past experience with my truck I know that a bad ground can cause some crazy things in an electrical system. Everything is properly ground as far as I can see. Since I was already concerned about bad grounds in the past I had also run separate ground wires from generator directly to battery. Share this post Link to post Share on other sites
Geno 1,929 #4 Posted July 21, 2014 Do you have a continuity meter where you can check all the grounds? Share this post Link to post Share on other sites
formariz 11,987 #5 Posted July 21, 2014 Yes did it and it all checks out ok! It's just driving me nuts. Everything on tractor works correctly too. Every time meter probes touch tractor it's like the thing is possessed. Share this post Link to post Share on other sites
swarfeater 49 #6 Posted July 21, 2014 is the generator polarized. starter gens need to polarized to gen in the proper direction, normally they will retain enough magnetism to not need it but once in a while they wont. this was a problem in a farm king I had that lost polarization every time it was disconnected. I forget which way but you have to give a quick fix by jumping either the field or arm to the bat post. Share this post Link to post Share on other sites
formariz 11,987 #7 Posted July 21, 2014 Wouldn't that cause it not to charge? Battery is always fully charged! Share this post Link to post Share on other sites
Geno 1,929 #8 Posted July 21, 2014 Wouldn't that cause it not to charge? Battery is always fully charged! That is correct. Hook the neg of the meter to the battery negative, take readings with the pos of the meter to the frame, engine and other various sheet metal, what do you get? Share this post Link to post Share on other sites
formariz 11,987 #9 Posted July 23, 2014 (edited) First of all meter gets readings just by getting close to tractor when it's on without probes touching anything. Does not do it with any other tractor. With tractor off negative probe on battery negative I get .001 to .005 on various parts of frame . With tractor on it gets crazy readings up to 17 volts with wild fluctuations. Meter also gets readings just by touching negative probe to all parts on tractor. Up to .007. Meter behaves perfectly normal with all other tractors. And again this is the best running most reliable tractor I have. Edited July 23, 2014 by formariz Share this post Link to post Share on other sites
Geno 1,929 #10 Posted July 23, 2014 You are getting voltage into the ground system somehow. It's either a grounding problem or a 12V wire shorted to ground somewhere enough to put voltage on the frame. If you're getting 17 volts with it running I would suspect the problem is before you get to the regulator. Check the wiring closely and check the grounds to the regulator and generator. It could also be the generator or regulator itself shorting voltage through it's casing to the frame. The meter going crazy when you get close without the probe touching is because the meter is picking up emitting votage, there is actually an electrical field around the tractor. I would't mess with it if you or the ground is wet because, well you know why... This is indeed an odd one. 1 Share this post Link to post Share on other sites
formariz 11,987 #11 Posted July 23, 2014 And I did use it in the rain a couple of weeks back! I am going to replace all ground wires and give it a good inspection tomorrow . Hopefully I will resolve it or it's just going to drive me nuts or worse give me a charge. Share this post Link to post Share on other sites
Geno 1,929 #12 Posted July 23, 2014 (edited) Another quick test. If you have a set of jumper cables you could clamp them between the battery ground and generator 1st, then other places to see if it helps also. Where are you at in Jersey? I was born there. Edited July 23, 2014 by Geno Share this post Link to post Share on other sites
formariz 11,987 #13 Posted July 23, 2014 Good idea. I am in Cedar Grove. Share this post Link to post Share on other sites
Geno 1,929 #14 Posted July 23, 2014 You are about an hour north of where I am from. I was born + raised in Freehold, close to Asbury park. Small world. Share this post Link to post Share on other sites
Save Old Iron 1,566 #15 Posted July 24, 2014 (edited) What type of meter are you using - a digital readout or an analog with a pointer? The digital meters can be very susceptible to radio frequency "static" from the chattering relays in the SG regulator and from the emissions in the solid core spark wire. If you have access to an analog meter - even a less expensive one - they tend to work better on SG systems and high RF environments. If you don't have access to the analog meter , try twisting the meter leads in a braid and making the measurement again. The twisted leads tend to cancel most of the interferences introduced into the meter leads by emitted RF energy. Think of the meter as responding to RF energy the way an AM radio picks up static from a fluorescent lamp fixture. Edited July 24, 2014 by Save Old Iron Share this post Link to post Share on other sites
Save Old Iron 1,566 #16 Posted July 24, 2014 think of the erratic readings as the same "signal" showing interference on voltage is the same "signal" by which you can measure RPM with a voltmeter by winding a single meter lead around the spark plug wire It is also the same "signal" used by the tiny-tach maintenance / rpm meters 2 Share this post Link to post Share on other sites
formariz 11,987 #17 Posted August 19, 2014 Finally found problem. Tractor has a dedicated trickle charger hardwired to battery and positive lead from charger had with time rubbed against a sharp edge on tool box wearing away insulation therefor exposing wire. Very hard to see since it was a very small area but what gave it away was the bit of "green" corrosion on wire like it sometimes happens on battery terminal . Just enough to let small amounts of energy to tractors frame. Meter now behaves normally and all readings are normal. Share this post Link to post Share on other sites
Geno 1,929 #18 Posted August 19, 2014 You are getting voltage into the ground system somehow. It's either a grounding problem or a 12V wire shorted to ground somewhere enough to put voltage on the frame. The meter going crazy when you get close without the probe touching is because the meter is picking up emitting voltage, there is actually an electrical field around the tractor. I wouldn't mess with it if you or the ground is wet because, well you know why... 99 0ut of 100 times it will be a voltage short to the frame. Glad you found it! Share this post Link to post Share on other sites
