Farmaster Generator

[JG4608]

Well since I have a generator I will post what I have. On the generator I.D. plate it has the following info.
Serial#: T12184
Model#: 275.151
Watts: 1,000
Volts: 115
RPM: 1,800

The Briggs and Stratton Engine has the following in its I.D. plate.
Model#: 14
Type#: 202034
Code#: 85502

It looks to me like the generator is DC and then on the box on top of the generator there is what looks to be a convertor which converts the DC to AC. There is also battery leads which I guess spun the DC generator like a motor to fire the engine and then the generator switched over to produce AC. I have a hard time keeping the comutators clean because the brushes seem to leave a black residue I have to clean off or she won't work. I would also like to know any info anyone might have son these generators because on of my brushes are disconnected and i do not know where to hook it up at? Also I am having with keeping governor in sync with 60HZ.

[Don Smith]

Not sure of your model but your information from the tag as listed shows that it is 120 vac output and not DC. To have the commutator get blackened from running would indicate that there is excessive arcing. This would indicate excessive current flowing when running. What size wires exit the generator that you are working with? Is there a ac recepticle mounted on the generator. Can you post a picture of the unit for us to view. Thanks Don

[Jim Rankin]

Could be 115V DC as well. You should look at the rotor inside. If it's capable of AC output it will have smooth sliprings as well as a segmented commutator (or only sliprings and no commutator)

If the sliprings or commutator are rough or have been resurfaced with a rough stone, they might grind the brushes. Normally a black track is ok and not a problem. It's possible that since you have a brush disconnected the slight increase in resistance from the black residue is too much. It's also possible that the brushes are deteriorating or the wrong grade of carbon for the job.

Brushes are sometimes connected in pairs, so if there are 4 brushes, they will usually alternate between + and - on a DC machine as you go around the commutator. So say you have a + brush at 2:00, there would be a - brush at 5, another positive at 8 and the last negative at 11.

If there are smooth sliprings, frequently there are multiple brushes on each slipring. In this case all the brushes on the slipring would connect to the same wire.

[JG4608]

Here are some pics. If you look it looks the rotor has both a comutator bar and I'm guessing slip rings but I am not sure. Also in one pic my finger is pointing to the brush wire which is disconnected. Any how I hope you guys can make something out of the photos.

[JG4608]

Here are some more pics I wanted to post also.

[Jim Rankin]

AC generator, no doubt. sliprings are next to the end bearing and the brushes there either feed DC power to the main field on the rotor, or the AC power could be drawn from the sliprings. I would trace the AC output wires back to their source to determine the type machine. The commutator is nearest the windings on the rotor. This is the DC part of the machine usually for both supplying excitation and maintaining the starting battery.

The control box seems to have a couple of large AC? relays, a 12 V control relay etc, some gauges and power resisters perhaps to regulate the voltage...........definitely no inverter componenets.

The large relays on the back plane of the compartment probably are probably to detect loss of utility power, signal to crank the set and then finally connect it to the load after voltage builds up. This should be enabled when the switch on the front is in the automatic position.

The brush lead that is loose almost certainly came from the connection screw under your finger. You might want to move it around and see where else it might possibly reach, but that's what I think.

[JG4608]

Well I am in the process of doing a little refurbishing on the Farm Master. I am going to split the engine at the base and wash out all the grime and sludge out of the motor so I can use a high detergent oil and not have to worry about a piece of sludge coming loose.

Also at each end bearing of the generator there are screw cap covers which allows you to lube the bearings. So what should I lube the end bearings with?

[Jim Rankin]

Usually any modern grease will work, whatever you have on hand that is at least 0 weight. I would remove both plugs if each bearing has two. That way you can purge the old grease that's in the end bells and totally replace it with the new. This will not usually purge the grease in the bearing itself completely, but will add enough new grease to dilute any old grease enough to restore it's viscosity. Leave the purge plug out and run the generator a minute or two to allow excess grease out and then replace the plugs. Should be good for the next 10-20 years!

[Jim Rankin]

In thinking about your description, I am guessing my description of a modern regreasable ball bearing "grease and purge port" system may not be what you have.

I have seen the old style grease cups that you remove the cap, fill with grease, screw it back on the cup, and then tighten down periodically to force the grease into the bearing. I don't think these use a lot of grease and should not since any excess most likely goes into the interior of the generator and contaminates things that should stay clean.

[K D Redd]

The box with the 12 volt sticker MAY BE a cut-out relay. If so the generator may act as a starter to start the engine. Look for a large post marked + and a starter soleniod. Clean the comutator and the slip ring and you may have power.
As a side note, the ignition coil on the B&S Model 14 Magnematic Magneto are bad about failing as the engine is run up to higher RPM. The engine will run fine at idle but misfire/run poorly as the RPM come up. Many people assume a carb problem. Coils a relativly expensive but I modify later point type B&S coils I have saved from junk engine to use on the Magnematic Mag. Look for a Nov. 2005 issue of Gas Engine Magazine for the article titled Cheap Fix. If you can not find the magazine, Jion the Briggs-N-Stratton Group on Yahoo. In the files section you will find the artical posted under Magnematic Fix.

Kent