Alternator in a generator case.

The are at least two companies that sell or rebuild them.♦ One is Tractoralternator.com and the other is♦ Genernator.com. The disparity is price is great which leads one to wonder whats up. Tractoralternator has a two wire 6 v positive ground that looks like a generator for $190.00. Same application from Genernator costs $900.00.. Go figure. Henry

So are these exact matches to the original generator as far as looks go? I mean, if somebody didnt know any different would it pass for original equipment? Also, it looked like the one at tractoralternator.com was a 6 volt alternator. Why is this preferable over a 6 volt generator?

Reliability, no external voltage regulator to go bad, alternators generally last much longer without repairs than generators. However, I would prefer 12 volts if I were converting to one of those. As to looks, I don't like the looks of an alternator on the A thru SA/SC-up on that style tractor -- looks out of place to me. So that might be the place for an alternator in a generator housing.

Found this post after I found that out. Yeah, that's a big disparity!

ADLM: I have a 6 volt alternator in my SA for 17 years. Reliability is what count in my books, if it looks like an alternator that is quite fine. Mine cost me about $50. new, same price as a new 12 volt alternator.

This whole issue of better starting of old gas tractors is often misunderstood. You have two separate and unrelated issues; 6 volt or 12 volt and generator or alternator.

6 volts will start any well tuned, pre 1958 gas Farmall, at temperatures down to -40F, as long as it has an excellent battery. 12 volt system will do no better. In fact I have a 6 volt Super A and a 12 volt 130 and a 12 volt 140. If I go to my unheated shop on a cold Canadian winter morning, the Super A will fire up as quick as the other two. What keeps my systems reliable, they are all alternators.

Next issue how do you keep a battery excellent? The alternator has proven to be far more reliable charging system, doesn't matter which voltage one uses. Alternators are by far, less costly to maintain.

(quoted from post at 02:01:41 07/11/09)This whole issue of better starting of old gas tractors is often misunderstood. You have two separate and unrelated issues; 6 volt or 12 volt and generator or alternator.

The alternator has proven to be far more reliable charging system, doesn't matter which voltage one uses. Alternators are by far, less costly to maintain.

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Excellent points, Hugh.
mike

(quoted from post at 20:12:21 07/10/09) The are at least two companies that sell or rebuild them.♦ One is Tractoralternator.com and the other is♦ Genernator.com. The disparity is price is great which leads one to wonder whats up. Tractoralternator has a two wire 6 v positive ground that looks like a generator for $190.00. Same application from Genernator costs $900.00.. Go figure. Henry

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looked at tractoraltermator web site and unless I'm missing something, I see nothing at all which indicates that what they are selling is anything other that re-built generators and rebuilt alternators.......nothing indicated an alternator inside a generator shell that I can see. Only the company name might lead one to that conclusion. Certainly amperes output numbers such as 11 amps would not lead me to conclude a unit is an alternator. So, at this point I'm a skeptic.

Both are alternators but the cheaper one has no regulator where the 900$ one is one wire with internal regulator. I am trying to find an alternator the looks like a generator for my A which has given me fits in the past 3 years. Two VRs and still no charge on a simple wiring scheme. First new regulator lasted 1 year and all the rubber dried out and it grounded out.the new one does not work again. Tired of this routine. Henry

(quoted from post at 15:06:50 07/11/09) Both are alternators but the cheaper one has no regulator where the 900$ one is one wire with internal regulator. I am trying to find an alternator the looks like a generator for my A which has given me fits in the past 3 years. Two VRs and still no charge on a simple wiring scheme. First new regulator lasted 1 year and all the rubber dried out and it grounded out.the new one does not work again. Tired of this routine. Henry

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K. You must have seen something on the site that I didn't or have contacted them?
I posted info a day or two ago about a solid state VR for generators......you might want to look into those.

(quoted from post at 18:33:18 07/10/09) So are these exact matches to the original generator as far as looks go? I mean, if somebody didnt know any different would it pass for original equipment? Also, it looked like the one at tractoralternator.com was a 6 volt alternator. Why is this preferable over a 6 volt generator?

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The big advantage an alternator has over a generator is that the alternator produces the electrical power in the outer, stationary winding.

Both generators and alternators produce electrical power by passing a coiled wired through a magnetic field. In a generator the magnets (field coils and pole shoes) are mounted inside the case and the wire coil (armature) is attached to the shaft and rotates. All the power produced must pass through the brushes to get out of the generator. As the armature spins there is arching as the brushed leave one commutator segment and slide onto the next. The commutator must be segmented because the current produced in the armature is alternating current. The brushes are arranged to only allow current to be drawn off in one direction. This quickly becomes a limiting factor in how much current can be passed through the brushes.

Electrically the alternator works the same way as the generator but the magnets (rotor) are spinning and the wire coil (stator) is attached to the housing. Diodes are used to limit the current flow in one direction only. This means that the current passed through the brushes now is only used to change the strength of the magnetic field and not the output current. Also the brushes can ride on slip rings rather than commutator bars resulting in much less wear hence the reason for the much smaller brushes.

The original IH tractor 6 volt generators were often limited to about 16 amperes, later ones were 25 amperes. 16 amperes is borderline for the lights, leaving nothing for recharging the battery after a start. Often the 6 volt alternators are 60 (or thereabouts) amperes, a big advantage.

Owen:
In addition to what you've explained, don't alternators make AC current (hence the need for the diode on the one wire versions) and generators make DC current? Inquiring minds want to know.....
mike

I posted info a day or two ago about a solid state VR for generators......you might want to look into those.

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I found what you posted...

http://ytforums.ytmag.com/viewtopic.php?t=502139

But $80 for a VR? ugh. How long are they supposed to last? I'm thinking, after reading all these posts on broken VR's, that maybe investing $200 on an altenator in a generator case might be a better long term investment.

(quoted from post at 14:33:23 07/11/09) Owen:
In addition to what you've explained, don't alternators make AC current (hence the need for the diode on the one wire versions) and generators make DC current? Inquiring minds want to know.....
mike

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The external diode is not needed on the one wire hookup. It is used with the three wire hookup which needs an external source of power to excite the regulator to get the alternator to start to charge. Once the alternator is charging current is available internally to keep the regulator working. This current also back feeds the wire used to excite the regulator. Since most farm equipment does not use an ignition switch with an accessory position that is separate from the ignition circuit, this back feed provides power to the coil on gas engines so that shutting of the switch will not shut off the power to the coil. This is not a problem with diesel engines unless you have an electrical shut off on the injection pump.


Electrically the generator and alternator work the same. In the generator the magnets are stationary and wire coils move. In the alternator the wire coils are stationary and the magnets move.

The current is generated by passing a wire coil through magnetic lines of force from the magnets. As the coil approaches the am pole end of the magnet the current will be generated in one direction. As the coil moves away from the pole the current is generated in the opposite direction. In a generator the armature is made up of many individual wire coils. The ends of each coil are attached to commutator bars 180 degrees apart. The number of coils in the armature is half the number of commutator bars it has.

The current produced in each coil of the armature is alternating current. The brushes are arranged so that the current can flow through them as the coil approached the magnetic pole. As the individual coil passes the pole of the magnet the current reverses in the coil but the brushes are no longer in contact with the commutator bars for that coil so the current produced in the opposite direction is not used until the commutator bars contact the brushes again after rotating nearly 180 degrees. The current in the coil is now flowing in the opposite direction but the brushes now contacting the commutator bars are now opposite of what they were before so that current flow through the brushes is in the same direction as it was when the armature was 180 degrees different. It is the way the brushes contact the commutator bars at the end of the wire coils that converts to AC current in the armature to DC current at the A terminal in the case.

Alternators use the same principles to produce current. Mounted inside the case of the alternator are three field coils called the stator. (They can have one end tied together in a common connection and three individual wire ends so that they form a "Y" shape or they may have their ends tied together to form a triangle or Delta winding. Delta windings will have three pairs of wire ends rather than three individual wire ends.) Inside the stator is the magnet mounted on the shaft called the rotor assembly. The rotor is made up of a wire coil used as an electro magnet and the iron ends that look like interlaced fingers. When current is applied to the inner coil one end of the assembly becomes a magnetic North pole and the other ends becomes a magnetic South pole. Because the fingers interlace they become alternating North and South poles all around the outside of the rotor. As the rotor spins these magnetic poles and their associated line of force are passed by the stator windings producing current in one direction as the pole approaches and current in the other direction as the pole moves away.

Diodes are necessary in the alternator to convert the alternating current produced in the coils to direct current usable with a battery system. Each diode is an electrical switch that allows current to flow in one direction only. A positive diode will have its base attached to the positive output stud. A negative diode will have its base attached to the alternator case. Each end of the stator coil is attached to a pair of diodes, one N and one P. One allows current to flow in one direction, the other allows current to flow only in the opposite direction. There are three wire coil ends (or pairs of ends in a Delta wound stator) so a total of six diodes are used. As current flows through the coil the P diode on end and the N diode on the other end will have the current flow through them. As the current is reversed in the coil, the other two diodes now carry the current. Because of the way the diode bases are mounted, the output flow form the alternator is always in one direction only.

Owen:
I believe I understand most of what you said. I was aware of delta and Y, primarily in 3-phase systems, but you have added clarity to my understanding of both. In addition, I was not aware that both types were built into various alternators.Thanks for going to all the trouble of an in-depth explanation. I think you must be an electronic genius.... Are you an Electrical Engineer? (You [u:29fa943482][i:29fa943482]must[/i:29fa943482][/u:29fa943482] be.)
mike