jrm@cbuxc.UUCP (John Miller) (11/11/85)
I have a 63 Ford model 4000 tractor. This is a full size agricultural tractor. It has a standard starting system and ignition system, the components are: 6v generator 6v starter voltage regulator 6v ignition coil 6v lights 6v starting solinoid (external to starter) The problem: The 6v starter system is crummy, it turns slowly and in the winter will sometimes not start. I have jumped it with a 12volt battery and found that the started (as expected) turns faster and the overall starting interval is shorter. The generator is not working, so I need to charge the battery periodically. When the battery has a full charge then it starts reasonably well (but still tough in the winter). Since the generator is shot and the battery is 3+ years old, I am considering converting to a 12 volt system. I would replace the generator and the regulator with a DELCO alternator (I would use one with a built in regulator), the ignition coil, lights, solinoid, etc with the 12volt counterparts. However, there is NO 12volt starter available - I must use the 6 volt starter. So the questions are: 1) can I use a straight 12 volts on this critter without a premature meltdown (what would the voltage drop be, etc.) 2) should I try to rig a voltage eater in series with the starter and battery: a) do they make a .048ohm/750watt resistor? b) is the an electronic way to do the same thing? (e.g. SCR etc.) 3) since the system is positive ground, can the case polarity of the DELCO alternator be reversed or can the starter be operated reverse polarity (since it is a D.C. motor I would expect it to run the other way?) Any help would be appreciated and yes I KNOW this is "net.AUTO.tech" not "net.TRACTOR.tech", but I had hoped that someone out there might be willing to tackle this problem anyway. j.r. miller, at&t bell labs, columbus, oh, us of a
bl@hplabsb.UUCP (11/13/85)
> I have a 63 Ford model 4000 tractor. This is a full size agricultural > tractor. It has a standard starting system and ignition system, the > components are: > > 6v generator > 6v starter > voltage regulator > 6v ignition coil > 6v lights > 6v starting solinoid (external to starter) > Not to mention a 6V battery. :-) > 1) can I use a straight 12 volts on this critter without > a premature meltdown (what would the voltage drop be, > etc.) You already stated that it works on 12V (when jumping it). > > 3) since the system is positive ground, can the case polarity > of the DELCO alternator be reversed or can the starter > be operated reverse polarity (since it is a D.C. motor > I would expect it to run the other way?) If you're going to change everything else, why not make it a negative ground? Dismantle the starter and switch the hot and ground wires.
ems@amdahl.UUCP (ems) (11/13/85)
> I have a 63 Ford model 4000 tractor. This is a full size agricultural > tractor. It has a standard starting system and ignition system, the > components are: ( generator, starter and solinoid, regulator, coil, lights ) > > The problem: The 6v starter system is crummy, it turns slowly and in the > winter will sometimes not start. I have jumped it with a 12volt battery > and found that the started (as expected) turns faster and the overall > starting interval is shorter. While in school, one of my friends was in the habit of buying old VW's of the 6v kind. We would then convert them to 12v. What we discovered was that 6v just didn't have enough left after line losses to turn the starter. 12v did a dandy job (as you have discovered). After the line losses there was about 8-9v left at the starter, which was fine. We never changed the starters or solinoids. > ... > Since the generator is shot and the battery is 3+ years old, I am considering > converting to a 12 volt system. I would replace the generator and the > regulator with a DELCO alternator (I would use one with a built in regulator), > the ignition coil, lights, solinoid, etc with the 12volt counterparts. However, > there is NO 12volt starter available - I must use the 6 volt starter. So the > questions are: > > 1) can I use a straight 12 volts on this critter without > a premature meltdown (what would the voltage drop be, > etc.) We did with no problems, just the curing of the 6v problem. > > 2) should I try to rig a voltage eater in series with the > starter and battery: We found no need for it. > a) do they make a .048ohm/750watt resistor? Yes, they are used in power converson equipment. It is a spiral of nichrome on a ceramic core. They are BIG and get HOT. But why bother? Most of the extra 6v gets used up pumping the starting current through all of the cruddy cables and connections (on older machines). > > b) is the an electronic way to do the same thing? > (e.g. SCR etc.) Yes, but at the current you are talking about it will be EXPENSIVE. > > 3) since the system is positive ground, can the case polarity > of the DELCO alternator be reversed or can the starter > be operated reverse polarity (since it is a D.C. motor > I would expect it to run the other way?) The motor may, or may not, run in 'reverse'. I don't know. Most DC motors, though, do have a polarity preference. I would try to convert the polarity of the alternator or get an alternator of the correct polarity. (Do British cars still use er, 'Positive Earth'?) > > Any help would be appreciated and yes I KNOW this is "net.AUTO.tech" not > "net.TRACTOR.tech", but I had hoped that someone out there might be > willing to tackle this problem anyway. > > j.r. miller, at&t bell labs, columbus, oh, us of a We would also leave the original coil in, unless it died. Often they would continue to work. We would change the major bulbs, that is headlights and taillights but leave the others. The instrument panel lights would often work just fine and be VISIBLE to boot. (Something they had not been before ...) In large measure, the 12v just fixed the failings of 6v and shortened the life of some bulbs. Keep a fire extinguisher handy during the 'smoke test' and don't worry about the small stuff. We never had to use the extinguisher, but tractors arn't VW's either ... -- E. Michael Smith ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems 'If you can dream it, you can do it' Walt Disney This is the obligatory disclaimer of everything. (Including but not limited to: typos, spelling, diction, logic, and nuclear war)
jacobson@fluke.UUCP (David Jacobson) (11/13/85)
> I have a 63 Ford model 4000 tractor. This is a full size agricultural > tractor. It has a standard starting system and ignition system, the ... > The problem: The 6v starter system is crummy, it turns slowly and in the > winter will sometimes not start. I have jumped it with a 12volt battery > and found that the started (as expected) turns faster and the overall > starting interval is shorter. ... > Since the generator is shot and the battery is 3+ years old, I am > considering converting to a 12 volt system. I would replace the > generator and the regulator with a DELCO alternator (I would use > one with a built in regulator), the ignition coil, lights, > solinoid, etc with the 12volt counterparts. However, there is NO > 12volt starter available - I must use the 6 volt starter. So the > questions are: > > 1) can I use a straight 12 volts on this critter without > a premature meltdown (what would the voltage drop be, > etc.) > > 2) should I try to rig a voltage eater in series with the > starter and battery: > a) do they make a .048ohm/750watt resistor? > > b) is the an electronic way to do the same thing? > (e.g. SCR etc.) > > > 3) since the system is positive ground, can the case polarity > of the DELCO alternator be reversed or can the starter > be operated reverse polarity (since it is a D.C. motor > I would expect it to run the other way?) > > j.r. miller, at&t bell labs, columbus, oh, us of a Disclaimer: I'm an electrical person more than an auto person. I've never even touched a tractor. First of all, trying to float the case of an alternator is a real loser. Try to switch to negative ground. The lighting system is not going to care. I've heard that the spark plugs might, but you are replacing the coil anyway. As for getting a resistor, that is easy: just use a piece of wire. Looking at the wire table in an old edition of the Handbook of Chemistry and Physics, I see that 12 gauge wire requires 629.6 feet/ohm. So for .048 ohms, that's 30.22 feet. The only question is can 30 feet of copper wire dissipate 750 watts for maybe a half a minute of hard winter cranking. That's 24 watts per foot or 2 watts per inch. I'm inclined to think it can. Just use those 30 feet of wire in place of an ordinary battery cable. Coil it up somewhere in a rather loose coil to let the air cicurlate around the wire easily. The starter won't run backwards, as long as its not built with permanent magnets. (Never heard of such.) Even so, I'm apprehensive about the scheme, since the 6v starter will use twice the current as a 12 volt one. (How will a 12v battery designed for the current requirements of 12v starters survive on a padded 6v starter?) Also motors aren't simple resistors, they depend on back EMF to control the current. (That's why a motor draws so much current with the rotor locked.) If the 120 amps your calculations indicate is the running current, with the series resistor it won't have as much low speed current as it would running on a 6v battery. Maybe that's no problem. Maybe its even a feature :-). I guess you could try my idea and see if there are any ill effects. An alternative is to talk to people at motor rewinding shops. Maybe someone would rewind your starter with more turns of finer wire. Twice the turns would provide twice the back EMF and everything would be fine. -- David Jacobson ... ihnp4!uw-beaver!fluke!jacobson John Fluke Mfg. Co., Inc., is not responsible for any of this.
ems@amdahl.UUCP (ems) (11/14/85)
> > I have a 63 Ford model 4000 tractor. This is a full size agricultural > > tractor. It has a standard starting system and ignition system, the > > components are: ... > > 3) since the system is positive ground, can the case polarity > > of the DELCO alternator be reversed or can the starter > > be operated reverse polarity (since it is a D.C. motor > > I would expect it to run the other way?) > > If you're going to change everything else, why not make it a negative > ground? Dismantle the starter and switch the hot and ground wires. Starters typically have the case as ground. It may be difficult to just 'switch the hot and ground wires' as various parts may depend on having the case be the ground wire ... -- E. Michael Smith ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems 'If you can dream it, you can do it' Walt Disney This is the obligatory disclaimer of everything. (Including but not limited to: typos, spelling, diction, logic, and nuclear war)
faunt@hplabsd.UUCP (Doug Faunt) (11/14/85)
> I have a 63 Ford model 4000 tractor. This is a full size agricultural > tractor. It has a standard starting system and ignition system, the > > The problem: The 6v starter system is crummy, it turns slowly and in the > winter will sometimes not start. I have jumped it with a 12volt battery > Back when I used to live on a farm, I saw two starters fried by jumpering from 12V systems, and also saw a 8V battery that was used for upgrading 6V systems for more performance. I didn't pay much attention, since I could hand-crank our tractors easily (I was younger then), but there is certainly some kind of hack that could be done. -- ....!hplabs!faunt faunt%hplabs@csnet-relay.ARPA HP is not responsible for anything I say here. In fact, what I say here may have been generated by a noisy telephone line.
levy@ttrdc.UUCP (Daniel R. Levy) (11/17/85)
In article <362@cbuxc.UUCP>, jrm@cbuxc.UUCP (John Miller) writes: >The problem: The 6v starter system is crummy, it turns slowly and in the >winter will sometimes not start. I have jumped it with a 12volt battery >and found that the started (as expected) turns faster and the overall >starting interval is shorter. A (perhaps dumb) question, and a (perhaps dumb) suggestion. When you jumper a 12-volt battery across a 6-volt system, doesn't that produce harmful current flows both for the 6-volt and the 12-volt batteries involved? Is this done with the 6-volt battery temporarily out of the circuit? Or is the 12-volt power just connected to the starter, with the starter otherwise out of the circuit (which is what I suspect....) As for the question itself.... Maybe something could be rigged up with TWO 6-volt batteries, normally charged in parallel from the generator/alternator, but reconfigured by a heavy DPDT relay or switch to be in series for purposes of cranking the starter if necessary? Then only during cold weather need the starter be operated overvoltage. Since the thermal inertia of the starter winding assembly is normally fairly great (note that most starters, maybe all of them, are operated at current levels which they could not survive continuously anyway) and the windings are well chilled anyway during such cold weather conditions, this may be safe under these conditions. (Someone wrote in to explain how they had burnt out 6-volt starters with 12 volts, however, so boost at your own risk.) The lashup is simple: +-----------------> to rest of electrical system | +------->---------+ / | | / | / | | / | +-------------0 0----> to starter | |/: | | _______ original 0 0 : / 0->-+-|- | starter / | | 6v | switch or / | |(extra)| relay 0 0 0-+---|+ | "Boost" | "Normal" |_______| ----- --- - -- ------------------------------- Disclaimer: The views contained herein are | dan levy | yvel nad | my own and are not at all those of my em- | an engihacker @ | ployer or the administrator of any computer | at&t computer systems division | upon which I may hack. | skokie, illinois | -------------------------------- Path: ..!ihnp4!ttrdc!levy