1983 MTD Products portable generator - need help please

[creia]

Hello All,
As I believe that most of you know, my son Jeff and I purchase vintage Briggs and Tecumseh "flatheads" that are non-running, missing parts, or otherwise have been abused/neglected and enjoy restoring them and bringing them back to life. Today we picked up a non-running portable MTD Products generator with a 5 HP Briggs engine (see information below) for cheap (only $ 20.00) mainly just for the various engine parts. After tinkering with it for about an hour and performing some minor repairs we now have the engine running fairly good. We then checked to see if the generator was working, however, there was no power coming from the (2) 120V receptacle outputs. Instead of just canabalizing the engine for parts, we thought it would be cool to get the generator working again, if possible. Can anybody provide us with some guidance ? Does anyone have an owners or parts manual or an on-line link to one for this generator? I will candidly admit that my son and I are complete newbies as far as working on portable generators! Thank you for any help you can provide!
Michael
Generator = MTD Products
Serial # 41-017-1726
Model # 244-712-000 K283D

Engine = Briggs & Stratton 5 HP
Model - 130232 Type - 1798-01 Code - 83021107

[KE4AVB]

I do know anything about this generator and not able to find this model number. I can offer is the two generator service manuals in the Briggs service manual library that are good source of information to learn about generators.

[Arkie]

I briefly searched using your model number and came up blank.

If you will email or call MTD they might can email you info such as a owners manual with a electrical diagram.
I have had to contact them and murray for info of products that don't show on their websites and they would both mail and email info.

Do you know if the gen has brushes or if it's brushless? Most old models have brushes under the end bell.
You can you tube about how to excite a brush and brushless type gen. Safest way for a brush type gen is to use a 9v transistor radio battery connected to the brush leads with a series blocking diode in series with the battery. (to prevent a higher voltage from back feeding into the battery if the gen starts working)

If you see two brushes maybe we can help you get it tested or excited.

Do you know how to use a voltmeter/ohmmeter? (vom or DMM)

Here is a link to ask about your gen model if you strike out with MTD. Lots of gen electrical guys with old stuff hang out here. Just post in the regular forum section after registering.
https://www.smokstak.com/forum/forumdisplay.php?f=6

You may know this. (just to give you an idea) Those gen engines usually have a tapered crankshaft at the gen end. Too make the motor useable so as to attach a pulley, etc to a standard shaft, save the reverse taper part of the gen rotor shaft. The crank and gen rotor are similar to a flywheel and crankshaft taper.

[Skywatcher]

Hi Creia

A portable generator creates electricity by spinning a magnetic field inside a shell of copper wires. Putting electricity through a copper wire generates a magnetic field and moving a copper wire through a magnetic field generates electricity. A generator relies on a small amount of residual magnetism in the rotor or armature to get the whole system working. When a generator has sat for a long time, the residual magnetism can dissipate so nothing happens when the generator is being spun by the engine. Flashing the field or exciting the generator refers to passing a small electrical current from an external source through the field windings to re-establish the magnetism in the rotor or armature and get the whole system activated.


First off, make sure the engine is running at 3,500 to 3,700 RPM (this will get you going in the right direction). Plug a trouble light into one socket and an electric drill to the other. Pull the trigger on the drill and give the chuck a few good spins. If everything else is in order, the light should come on and the drill should start spinning, generator is now re-energized. Let us know what you find,

Sky

[KE4AVB]

The two fore-mentioned service manuals will address how flash both the Direct and Indirect exciters. On the indirect exciters two methods are explained. These manual also covers all other aspects of portable generators. Some manufactures will vary in their application of these theories but all will generally follow the same rules and test procedures.

The electric drill method only works if the drill's electric motor is of the permanent magnet type; induction type will not work as it generates no voltage hand spinning it.

Two pole generators that are producing 60 hz will need to run at 3600-3750 rpm. Four pole generators that are producing 60 hz will be half this rpm, 1800-1875 rpm. Four pole generator are usually diesel powered.

[Arkie]

AND be careful when using the drill method If the gen starts producing electric the drill will start spinning immediately.

I've heard of some using a 120v brush type drill and set it's rotation direction to forward then take a battery operated drill and spinning the 120v brush type drill with the battery drill while holding down the trigger on the 120v drill.

I would just try sinning the 120v drill by hand first.

If using a battery operated drill to spin the 120v I would consider using the clutch setting on the battery drill and be ready for a run-away.

This drill method is mostly used on a brushless type gen but will work on both brush type and brushless.

Another method for brushless is the more hazardous light bulb method. If not careful you can get 120volts on the frame of the gen. Do not use this method unless you fully understand the hazards involved. You might temporarily excite yourself and then your lights go out.

[KE4AVB]

Another method for brushless is the more hazardous light bulb method. If not careful you can get 120volts on the frame of the gen. Do not use this method unless you fully understand the hazards involved. You might temporarily excite yourself and then your lights go out.

Nor would I recommend or even consider this method. Everything be insulated from earth ground. IF this does not make sense take a 110-125 vac power cord out to the yard with a volt meter. Now insert one lead into the ground with your voltage meter set for AC. Then using the other (without touching any metal) probe the power cord plug in. You will find that one side will one will show the line voltage. This because the neutral leg of our electrical systems is earth grounded at your meter base and at every home and business in the area. I personally have ran an one wire power setup in temp applications here when I did didn't enough lead so I use my electric drill for a few minutes. This I don't recommend anyone doing unless you are aware of you work surroundings.

There is much better and safer method in the service manual where you use a battery on brush-less generators to restore the residual magnetism to the rotor.

Btw the light bulb method requires two lights wired so each of the supply lead has a bulb is series in each lead. That way there is always a load and not a direct short to earth ground or neutral. Use a three wire power cord as it has a safety ground. This way you will never have the 120v on the frame especially if you earth ground the frame or have it setup with a bonded neutral.

>-----120 v Bulb------>
>-----120 v Bulb------>
>---Safety ground --->

[creia]

Many thanks to all that replied- the information you provided is duly noted and very much appreciated.
I did call MTD Products technical support and got SOME information. They informed me that MTD was only in the generator business for a little over 3 years, during the mid-1980s. While they could not locate any information for my exact model #, they did find in their "hard" file and owner's manual for a similar model, so they scanned it and emailed it to me. I am still w/o a parts diagram or wiring schematic. Being that this generator was such limited production, I'm assuming that obtaining any parts will not be likely. Also, I did post my question on the Smokestack Antique Engines forum and did get a reply about "flashing" the generator similar to what has been suggested here. I still think it would be cool to try to get the generator operating first instead of just canabalizing the engine for parts. I'll provide an update and any success I have in a future post.
Michael

[Arkie]

You will find that most of them old model emergency gen dogs are more reliable and desirable than the later models
and hopefully not any major parts are bad and even on the later models if major parts are bac, like rotor, stator, new parts are too expensive as compared to price of a complete replacement gen.

The KW ratings on the old model gen's was generally conservatively rated vs the new models gens that KW rating are not real world rating.

Most of the old model gen's had brushes also, and if you find that it has couple brushes under the end bell, get back to us and we can give you some hints about SAFELY exciting and testing.

[creia]

Update: SUCCESS!!
After adjusting the governor and (fixed) speed control I now have a working generator. At 3,600 rpm it is putting out 130V with no load. When I start plugging in power tools (power drill ,then an angle grinder) the RPM drops initially by about 150 RPM, the comes back up to about 3,550. The generator voltage goes down (and stays at) about 127V with these 2 tools plugged in and running. Does this all sound pretty normal? This generator only has 2 receptacles to plug into for power. What do you think the total wattage of this generator is rated at? Is the "no-load" rpm setting of 3,600 correct?
Michael