Generator & Cut Out Information, Operation, Repairing, EVR installation!!!

[Mitch]

Generator Brushes and Adjustment and How It Works.

By :: Tom Wesenberg



I'm asked quite often about brush adjustment and how they work, so hopefully these pictures will help.
The first picture is a cutaway taken at the Model A museum at Gilmore Auto Museum in Hickory Corners, Michigan. The second picture shows the 3 brushes. This happens to be the style with a ball bearing in the rear, as used until about March 1930. At that time the bearing was changed to a bushing and the output stud was moved from the front of the case to the rear.

The brush on the left is the output ground brush and has no insulators on the brush holder.
The top brush is the adjustable brush (third brush) and it sets the generator output amperage.
The brush on the right is the output brush and connects to the output stud in the generator case.
Notice all 3 brushes have a long and short side, and the short side is always closest to the brush holder pivot post.
Also notice the adjustable field brush is thinner than the 2 output brushes.

The adjustable brush connects to the field windings, and the other end of the windings is connected to ground. So, consider the ground brush as 0 potential and the output brush as 6 volts potential. Now you can see that as you move the adjustable brush (field brush) closer to the output brush, you will increase the voltage feeding the field coils. This will increase the magnetism of the field poles, which increases the generator output.

So, you can see this also becomes a runaway situation. As the field gets stronger, the output increases, and this also increases the output to the adjustable brush, and it becomes a vicious circle. However since the output is connected to the 6 volt battery, this keeps the output under control. If you have a poor connection in the charging circuit, then the battery is no longer connected and the voltage can rise to as high a 40 volts. This can smoke the field windings and cook the armature. If the lights are on they will also burn out.

With the generator on the car, as you face it from the front of the car, the adjustable brush will be about in the 2 o'clock position. Moving the brush UP lowers the output, and of course moving the brush DOWN will increase the output. For most daytime driving a couple amps should work fine. The more amps, the more the water is evaporated from the battery. If you do a lot of starts and short drives, or night drives, then you will need to move the brush down for more output.

This picture shows too much grease for the rear bearing, and I removed about half of it before the final assembly. I also put a thin coat of grease on the adjustable brush ring and 2 tension holders, and a drop of oil on each of the 3 brush pivot posts.

[Tom Wesenberg]

Cutout Identification

Original cutouts can be easily identified by the looks and weight. They are about 50% heavier than the cheap repro cutout. Originals have the cover held on by 2 spot welds on the lower edge of the cover. Also note the shape of the insulating board on the bottom. I only use original cutouts, and have never had a problem with them. I adjust the air gap to about 020" for the contacts, and make sure there is a small air space over the armature (center coil post) when the contacts are closed


Original Cut Out

A0183B23-DA6D-4E51-A043-EB622CF855FD.jpeg

[Tom Wesenberg]

How a Cut Out works!

The cutout is simply an OFF-ON switch to disconnect the battery from the generator when the generator puts out less than battery voltage. Here is a good schematic of the cutout showing the two windings. The fine winding pulls the armature down to close the contacts, and the current flowing through the heavy winding helps hold it closed. When the generator voltage falls below battery voltage the battery current will reverse direction and run back into the generator. This will reverse the polarity of the heavy winding and cancel the pull of the fine winding, thus opening the contacts.

cut out.gif

[Tom Wesenberg]

Cutout Disassembly Tool

Here's a homemade tool to hold the cutout so I can split the two spot welds. Once the cover is removed the bends can easily be straightened. The cover will fit tight and the 2 terminal screws will also hold it in place, so there is no need to solder or spot weld it in place. I adjust the contacts to close between 6 and 7 volts. The open contacts should have an air gap of about .020". Notice my variable power supply shows 7.1 volts, but that's because it's upside down. In the upright position it will close at 7.0 volts. The weight of the armature makes the difference. The closed mounting feet mean this is a later Ford cutout, which is often used as a replacement on Model A's.

The 4th picture shows what the cover looks like after sandblasting and plating with my Caswell "copy cad" plating kit, which is actually zinc plating. I then lightly brush the plating with my well worn brass brush to make it look more correct.

[Tom Wesenberg]

Motoring a Generator

When you use a jumper wire between the 2 cutout terminals, you polarize it, but if the belt is off and you leave the jumper wire in place, the generator will motor. It will turn slowly in it's normal direction of rotation. I tested my generator by using the EICO power supply I recently bought and repaired.
At 6.2 volts the generator will draw 5 amps.

power.jpg

[tbirdtbird]

This motoring trick always intrigued me as a way to test a generator that you picked up in a junk yard.
If it motors, it must therefore be good as a generator. After all they are practically the same thing. There are those that claim this is an invalid test, and I frankly don't get that. Tom, maybe you can comment. It always worked for me for many years.

The only thing that I have learned from this trick, is that since the windings were really made for it to generate and not motor, the fields seem to heat up very quickly, and if you motor it for more than a minute it gets hot and slows way down. It only takes a brief moment to do your motoring test, so don't over do it! And as a motor, it has very little torque.

[Tom Wesenberg]

Usually if it motors, it will generate, but I have had at least one in the past 10 years that motored, but had no output.
I don't recall exactly what the problem was, but I'm thinking it was in the field windings.

[tbirdtbird]

I truly do not understand that; you need a functioning field and armature for both to work, so if it motors how cannot it not generate LOL

[pAAt]

Tom, I have my eliminator in the garage, waiting for you to show me how to use it. The nice one I got, the other on is on hold until he gets back to it ?

[Tom Wesenberg]

We got 4" of snow today, but tomorrow I'll shovel a path to my small shop and remove the field wire from the brush and see if it still motors.
Too early for all this snow and salt. I should move everything back into my basement.

[George Miller]

This motoring trick always intrigued me as a way to test a generator that you picked up in a junk yard.
If it motors, it must therefore be good as a generator. After all they are practically the same thing. There are those that claim this is an invalid test, and I frankly don't get that. Tom, maybe you can comment. It always worked for me for many years.

The only thing that I have learned from this trick, is that since the windings were really made for it to generate and not motor, the fields seem to heat up very quickly, and if you motor it for more than a minute it gets hot and slows way down. It only takes a brief moment to do your motoring test, so don't over do it! And as a motor, it has very little torque.

This works most of the time, but in the old days working in my Dad's garage working on cars there were a few times when it did not work. I cannot say why, but it happened more than once.

[Tom Wesenberg]

OK, I just went out and did the motoring test with the field wire disconnected. It still motors, but now draws 13 amps instead of just 5 amps.
So, if you have a generator problem keep these figures in mind to help identify the problem.

[tbirdtbird]

electricity and magnetism are 2 sides of the same coin
from the purely academic electromagnetic point of view i cannot fathom how a motor can work with no field

maybe we can get Watt, Coloumb, Tesla, and Newton to sign on to the VFF, surely Mitch has a secret way for special guests. Otherwise I'll have to wait for my next seance

[Tom Wesenberg]

BTW, one thing to watch for is where the field windings wires are twisted together and soldered. Make sure this doesn't touch the long through bolt, and make sure it's a good solder joint. I had to work on an intermittent generator problem about 10 years ago, and found the twisted wires weren't soldered, so they sometimes had high resistance.

[Tom Wesenberg]

Repairing a bad Generator Armature

I was sent an armature to repair some wires that got scraped away. I've never seen this happen before and wonder just what rubbed so long that it wore away some of the wires leading to the commutator. It must have been the field wire or power brush to stud wire. I had to splice in some short lengths of solid copper wire after I scraped away the lacquer coating. I also had to turn the damaged taper where someone had pressed or hammered against the front end. With the damage the pulley wouldn't mount correctly. A longer bolt should always be run to the bottom of the threads to press against, or tap with a hammer.

After the wire repairs I tested it on my growler, and once it passed that test I polished the commutator, repaired the taper, then sprayed the front end with clear shellac, and used Loctite slow set clear epoxy to hold the commutator wires in place. It should be set up enough by tomorrow to mail it back to the owner.

[Tom Wesenberg]

More 3rd brush info


The adjustable ring should be held in place by two Y spring clips, which are held in place by 2 screws.
They don't need to be loosened to move the adjustable brush ring. The ring may be stuck from years of never being adjusted. Usually using the opening as a fulcrum for a screwdriver against the spring post on the ring will get it to move.

Post Model A production end plates have the adjustable ring Y spring clips held in place by rivets, but the generator output is adjusted the same way.

If you buy an electronic voltage regulator from me it's important to know which end plate you have, as the EVR for the rivet one is different than the EVR for the screw end plate. The second picture is the post Model A production with the riveted Y clips.

Generator End Plate A.jpgGenerator Brush Plate B.jpg

[Tom Wesenberg]

Instructions for installing the Autolite style EVR

Remove the field and output wires from their brushes, then remove the rear end plate.
Remove the two screws holding the adjustable brush ring, then remove the ring.
Reinstall the screw and Y clip for the ground brush wire.
The adjustable brush with it's holder and Y clip will go to spare parts.
Install the other screw through the EVR, then the spacer, then into the end plate.
The notch in the EVR will line up with the hole for the long through bolt.
Notice the brushes have a taper and the short side always faces the pivot post for that brush.
If you use a diode cutout, then you must cut the short blue wire (color may vary). Just be sure the ends don't touch each other.
Install the EVR wire to the output brush exactly as pictured, then install the end plate to the generator.
Loosen the screw for the output brush and install the generator output wire from the output stud.
Install the field wire under the screw on the aluminum heat sink.
A stock cutout must close the contacts before 7 volts is reached, or you'll have no output.
At fast idle, if you have 7 to 8 volts at the output stud, but only battery voltage on the cutout output side, then the cutout needs to be serviced or replaced.

[Tom Wesenberg]

Instructions to Install the EVR in the B Style Generator



Here are pictures to show EXACTLY how it should be installed. Notice the corners of the circuit board rest at the mid point of the raised lip on the end cap. This is important, and you may have to bend the brush holder slightly to get this position. The hole in the heat sink is slightly off center to keep the heat sink from hitting the round transistor, so be sure it doesn't get flipped half way around. I use a screwdriver to slightly lift the adjustable brush ring and slip the green wire under it. Route the wires exactly as shown in the pictures. Notice the brushes have a bevel which contact the commutator. The shorter side of the brush always faces the pivot post for it's brush.

After it's installed and back on the car be sure to polarize the generator by jumping the two terminals on the cutout with a short wire for one second.

WARNING, be sure your system is 6 volt positive ground only. Also, since the generator voltage is now regulated to a safe output voltage of about 7.2 volts, the cutout must close it's contacts before this voltage is reached. I adjust them to close at about 6.0 volts.

If you use a diode cutout, then the small wire loop on the bottom of the circuit board, just to the left of the EVR mounting screw, must be cut and the ends moved just enough to not touch. If you go back to a stock cutout, then resolder the two ends.

[Tom Wesenberg]

Instructions for Installing the EVR on a 3 Brush Powerhouse

Remove the adjustable brush and keep it in your spare parts.
Remove the other 2 brush terminal screws.
Lay the EVR over the brush spring posts as pictured, then install the brush terminals as pictured.
The generator output wire is on the left side of the picture and under the EVR.

If you use a diode cutout, there is a small wire loop that needs to be cut, and make sure the wire ends don't touch each other.

[Tom Wesenberg]

Instructions for Installing the EVR on a 5 Brush Powerhouse

Remove the adjustable brush and store it in your spare parts.
Remove one ground brush screw and one output brush screw, then lay the EVR over the brush terminals as pictured.
Reinstall the 2 screws and make sure the brush flag terminals and bare wire don't touch any components on the circuit board.
The 2 brush flag terminals will lay on top of the posts and make contact with the circuit board when the screws are installed.
Slide the adjustable brush post to a position to line up with the output transistor and heat sink, then reinstall the screw and field wire.

If you use a diode cutout, then you need to cut the small wire loop on the bottom of the circuit board.

[Mitch]

Generator Specifications Type Two pole Voltage Regulation Fixed control Brushes 3 (1 adjustable) Armature Bearings 29-Mid ’30: Ball front & rear After Mid 30: Ball front, bushing rear Armature Speed 1-1/2 of engine speed Armature Length 28-April ’30: 7-9/16" - uses 1-5/32" wide pulley after April 30: 7-21/32" - uses 7/8" wide pulley Max. Normal Charging Rate 12 amps @ armature 1600 rpm (25mph) Cutout Closes Approximately 9 mph Cutout Opens Approximately 8 mph Contact Gap .015" to .020" Core Gap .010" (contacts closed) Brush Spring Tension 25 to 40 ounces each Field Coils 100 turns of #17 copper wire Armature 14 coils with 6 turns of #17 copper wire Commutator 28 copper segments Field Current Draw 6.3 amps at 7 volts, generator (motoring draws 5.75 amps at 7 volts) Maximum Current 18 to 22 amps at 6 volts Motoring Freely 5 amps at 6 volts Field Test 5.2 amps at 6 volts The very earliest Model A Fords were equipped with “Powerhouse” generators (shown below), which had a pancake shape & a body covered with sheet metal. Soon Ford replaced them with the more familiar generator that is shown below. These generators, when working properly, are simple, durable & reliable. Photo Captions: 1. Cut-Out 2. Cover band 3. Pulley 4. Rear End Plate

[Tom Wesenberg]

Generator ready for blast off w/ EVR install:

Original Thread Link!


Getting the generator ready to blast off someone's poor paint job. The generator is in very good basic condition, but it is in need of a good restoration. The only sign of anyone having ever worked on it is the friction tape on the output wire. The picture shows where some of the field coil wrapping has fallen off. It may have overheated at one time, or just dry rotted away. It doesn't smell like burnt windings, and when I connected my battery charger + to ground, and - to the field wire, it draws 4 3/4 amps on 6 volts. This means the windings are good, so I'll coat the missing wrap with "Liquid Tape" and continue restoring it. The Liquid Tape will help protect the windings and help to keep them from vibrating.

The band is the correct style for 1931, and the date stamp matches the time the car was built, so most likely this generator is still the original one that was on the car when it was new. This has a date stamp on both ends of the band, which I don't see too often. I don't know why Henry would have allowed the extra time for a second stamping. I made two rubber pads and aluminum discs to protect the windings when I do the blasting. I first used gas and a soft paint brush to get rid of any dirt and oil. The picture shows blasting with the mounting bracket still in place, but I just wanted to get started and take a picture, then look for my impact screwdriver to remove it, and finish blasting.

[Swastler]

Like the winding protection while blasting, good idea!

[Tom Wesenberg]

Notice the band has a date code L4, which is the 4th month of 1931. The armature also is stamped 4-31, so this generator appears to have all it's original parts. The strange thing is that when I removed the 4 original rivets to remove the front end plate, the wavy washer was missing. Seems like this is most likely an original factory screw up. Now I've got all the parts painted and hanging on the basement clothes line and across the top of the laundry tub. After the paint dries for a few days, I'll reassemble it. In the meantime I can check out the armature and replace the ball bearing.

When the bearing separator is clamped around the ball bearing, be sure it isn't too tight, or it will grab the inner lock ring and deform it as the puller tries to pull it out of the groove. Always screw a bolt into the end of the armature for the puller to press against, or you can deform the taper on the shaft. You can see the commutator is the full diameter, because no one ever cut it, as there is almost never a reason to turn the commutator. I'll use my thin Atlas hobby saw to clean the grooves, then give the commutator a light polish on my lathe.

[Tom Wesenberg]

I forgot to show the picture of the wavy washer that's missing. In the top row is all the parts that should be assembled to all the long style Autolite Model A generators. The wavy washer is the third part to the right of the front end plate. A new sealed front bearing will replace the open ball bearing, so no oil will be needed for it. The rear bushing can get a few drops of oil every couple thousand miles.

The bottom row shows the bearing parts used until March 1930, when a bushing replaced the ball bearing.

Generator Bearings 1929 Exploded View.jpg

[Tom Wesenberg]

OK, I finished blasting all the parts, painting them, and giving them a few days to dry. Now it's time to put it back together, and the owner wants an EVR installed.
Take note of how the ground brush wire terminals are positioned. This is the only way they fit correctly and give the best service. Also notice this commutator is full diameter, as no one has turned it down. The EVR is a very close fit to the commutator and lip on the end plate, so watch for clearance in both these areas if you install an EVR. This cast iron end plate has a raised area for the EVR mounting screw, so the aluminum spacer I send with the EVR won't be needed. One picture shows the C retainer for the front bearing and spacer. This is made of soft steel and can be spread apart easily for removal, then squeezed tight with ordinary pliers when it's reinstalled.

I put a drop of oil on each pivot post and each spring, then spread a few drops of oil on the bare metal of the end plate. Just be sure no oil or grease gets on the commutator or brushes. I also put a few drops of oil and a dab of grease into the rear bushing. When it's all assembled use a flashlight to study the field wire and the output brush wire to be sure they don't rub each other and don't rub the armature or heat sink on the EVR. This is one of the nicest generators I've done, because no one left it in the weather to rust, they didn't mix up parts, and they didn't do any physical damage to it. Picture 6 shows the wavy washer that was missing, and seems to be a factory mistake for leaving it out. I replaced it with one out of my own generator. You install the front retainer, then the felt, then the wavy washer before riveting the front cover back onto the bearing retainer. I always use the rivet screws the dealers sell.
Follow these pictures exactly, and you should have no problems. BTW, this is Rustoleum 2X semi-gloss black.

[Tom Wesenberg]

Finally done and ready to mail back to the owner. I guess the picture would have been better if I took it outside, but it's snowing again. Someone said they didn't like Rustoleum 2X, but I think it's the best I can find in a spray can so far. Just have to remember that 2X seems to mean it comes out twice as fast, so go fast or you'll get runs. Two light coats of semi-black works well for complete coverage. Notice the position of the band screw is towards the outside of the car with the nut down.

Generator L4 Finished.JPG .

[Mitch]

Cutout from Model A Basics

A special thanks to Paul Modlin

http://modelabasics.com/Cutout.htm

Driving tip: While driving and using an original cutout, periodically check the Ammeter to see if the system is charging. The Ammeter can be used for a quick check for the cutout. With all electrical accessories off, the Ammeter should read to the right while driving, and zero when the engine is at low idle or turned off.
The Cutout In its simplicity a cutout is a magnetically controlled switch that provides a path for current flow from the generator to the battery. The cutout permits charging of the battery when the engine is running and prevents the battery from discharging when not.
The Coils Inner Coil-The inner coil is made up of multiple windings of a thin wire around an iron core. The fine-wire winding is just enough to get the points to close when the generator voltage rises above 6.2V or so. Its only purpose is to create a magnetic field to pull on the armature until the contact points close. By itself the magnetic field created by the inner coil is not strong enough to keep the points closed when subject to vibrating. Once the points close, the heavy-wire (Outer Coil) begins to conduct, creating a strong magnetic field that aids the inner coil in keeping the contacts firmly closed. Outer Coil-The outer coil is made with a heavy wire and few windings. With the points closed current from the generator travels thru the outer coil charging the battery and strengthening the magnetic field around the iron core which prevents the points from vibrating open.
The Points Contact Points-The contact points of the cutout act as a switch and are held “Normally Open” by the armature spring. When the speed of the generator increases a magnetic field is created closing the points, thus, allowing current from the generator to flow and charge the battery. If the generator voltage drops below battery voltage, such that the battery begins to "charge" the generator ,instead of the other way around, the current in the heavy winding will be reversed, which means it's magnetic field will work AGAINST the fine winding, and cause the points to open. The point of "cut-in" (closure of points) is determined by the tension of the armature spring and the air gap between the iron core and contact arm. The contact points should close when the voltage of the generator has reached 6.1 to 6.3 volts. It is possible to change the "cut-in" by adjusting the air gap and/or bending the Armature Spring. (The "cut-in" charges the battery) The point of "cut-out" (opening of points) is determined by the tension of the Armature Spring. The air gap between the contact arm and the iron core has little or no effect on the "cut-out". The cutout should occur when the ammeter reads between 0 and 2 amps. It is possible to change the "cut-out" by bending the Armature Spring, set the "cut-out" as close to 0 as possible to prevent points from arcing and burning out. (The "cut-out"stops the charging of the battery and prevents the battery from draining)
Testing Cutout On Car Equipment: • 3/4 Ohm Resistor • DC voltmeter Disconnect the battery wire from the Battery Terminal on the cutout Install a ¾ ohm resistor to the battery terminal of the Cutout. Connect the other end of the resistor to a good ground. * Start the engine and slowly increase the engine speed The cutout should close between 6.1 to 6.3 volts*. Which will be evident by a sudden drop in the voltage reading.
To Adjust Remove cutout from generator Flip cutout over and break the two spot welds Remove the cutout’s cover Slight adjustments can be made by changing the air gap If the voltage is less than 6.1 volts increase the springs tension by bending the bimetal downward. or increase the gap If the voltage is more than 6.3 volts, decrease the voltage by bending the spring upward. or decrease the air gap.
Printable version of above assembly drawing

Printable pdf of above drawing





Visual Comparison of the early and later style of cutouts.













5DA4BAE7-4555-4C34-8848-BEBB014FED8F.jpeg

[Tom Wesenberg]

Well, this is sure timely, as I was just getting ready to post about the same thing. This morning I took apart a generator to restore, but then had to take apart a second one, in hopes enough good parts from two will make one good generator. The shaft moved in and out a 1/4", and it also moved about 1/8" radially. With minor bearing spinning on the shaft, I can correct it by knurling the worn area with my lathe, but this shaft is way beyond knurling. It even wiped out the rear snap ring groove. Someday, when I have spare time, I will weld it and turn it to size, and put the lock ring groove back in.

It's a shame the front bearing wasn't kept oiled, as the commutator is in mint condition. This is why I install a sealed front bearing on generators. Of course before doing any work on this armature, I'll have to test it first on the growler, to see if it's even worth saving.

Armature Worn 1.JPGArmature Worn 2.JPG

[Patrick]

Always try the easy things first!

Went to wake the old girl up
this week from her long winters nap. She started right up but wasn't charging.
Gave the cutout a few taps, nothing. Closest other thing was a pair of pliers [ why are pliers called a pair ?] , opened them up to jump across the terminals, zap, and its charging. I'm a bit surprised that happened just sitting for one winter. Maybe she is just letting me know she doesn't want to get left behind next winter.

[Tom Wesenberg]

Long Generator Endplay

I just had a question about end play on the common long generator. It's the front bearing that controls the end play, so if you can move the armature in and out more than a couple thousandths of an inch, you should plan on installing a new front bearing. The rear bushing (used March 1930 and later) almost never needs to be replaced. Often you can get by with a new front bearing, rivet/screws to install the bearing, and a set of brushes. Hopefully the bearing isn't so worn that it spun on the shaft, but even that can usually be corrected by knurling or using a center punch to make a lot of punch marks in the worn area.

In the electrical section is information on removing and installing the bearing. Be sure to use a puller and don't hammer on the end of the shaft.

[Tom Wesenberg]

Manually adjust your generator output

Here's a switch to vary the fan speed for the electric motor on a heater, but it can also be used to vary the generator output. Just remove the cover band and unscrew the field wire from the adjustable brush. You can then run a wire from the adjustable brush, and another wire from the field lead, to this switch. This switch can be turned to vary the resistance to the field wire, so you can dial in the amps output from the dash.

https://www.ebay.com/itm/NOS-RED-HEA...sAAOSw38BaZ4LV


heater.jpg

[Mitch]

8AE25956-DD79-4FA9-9BAB-A6F6CB4FF871.jpeg85FEE43E-6907-4969-ABC0-ACD1E72EE346.jpeg

[Mitch]

Voltage to Amps conversion chart
Basic generator info

Scan0054.jpg

[Tom Wesenberg]

How do I know if I have a Diode Cutout!

Original thread

I see this question quite often, so here is an easy check.

The diode is a one way valve for electricity. If you have an ohm meter, then disconnect the wires from the output side of the cutout, and connect the two ohm meter leads to the 2 cutout terminals, then reverse those 2 ohm meter leads. If you have a diode cutout, the meter should show near 0 ohms in one direction, but show infinity in the other direction. In other words, the ohm meter needle will swing full scale one way, and not move when the leads are reversed.

If you have a battery powered continuity tester, then connect that to the 2 cutout terminals, and reverse the connections. The light should turn on in one direction, but not in the reverse direction. Be sure the wires are disconnected from the output side of the cutout when making these tests, as you want the cutout out of the circuit to get accurate readings. Also battery voltage can damage an ohm meter.

A diode cutout should show no continuity from either terminal to ground, and both terminals must be disconnected for this check.
A stock cutout should show about 40 ohms from the input side of the cutout to the case, and the output terminal should show no connection to anything.