powerhouse generator question

[steamgas]

I am in the process of restoring the powerhouse generator. I have the rotor motoring just fine and in the right direction. I polarized the field winding. I checked the cutout and all looked like it should work. Here is my problem,when i rotate the generator on a test stand it acts like there is not enough residual magnetism to pull down the upper point, in other words the generator is not charging. I have checked everything that i can and don't see anything that can keep it from charging. I am missing something here and need your all's help to solve this mystery.
Tex

[Kurt in NJ]

What is the voltage generated at the post before the cutout
Has the armature been tested on a growler?
If it was tested what testing was done
Sometimes the connection for the ground from the brush to the case, I have had to clean and solder the connection in the brush rigging

[katy]

when i rotate the generator on a test stand it acts like there is not enough residual magnetism to pull down the upper point,

How fast are you rotating the generator pulley? You probably need 1000 or more RPM to get it started generating.

[steamgas]

Yes i tester the rotor on a growler.i checked from commentator bar to bar, i checked continuity from commentator bars to the stack lams with no fault, i checked for internal shorts with no faults.

[steamgas]

At this time there is "zero" volts at the output terminal.

[rotorwrench]

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Motoring isn't always the best way to get residual magnetism in the field pole shoes. The best way to do it is to isolate the 3rd or movable brush from the commutator and jumper direct to the field wire on that brush or disconnect the wire from the brush. The ground on the other end of the field also needs to be clean and tight. Tom Wessenberg always said to check the field coils by installing an ammeter in between the power source and the coil and then apply power to the filed coil and see how much current it will draw. The amount depends on the configuration of the dynamo, whether a 5 brush or a 3-brush type.

This link has a post by Tom on current draw for all three types of fields. He used a battery charger with it's own amp meter to test. This will polarize the pole shoes.
https://www.fordbarn.com/forum/showthread.php?p=1517922

There are plenty of other problems that can happen so a person has to growl and continuity test the armature, then inspect the brush plate for any signs of loose connections (especially the 5 brush units). Make absolutely sure that armature and field coils are insulated well even if they have to be resprayed or wrapped. Check the air gap between the armature and field pole shoes. They should be pretty close. If the gap is more than .010" then the magnetic gauss or field strength becomes less effective. I'm not sure on maximum limits for the powerhouse but they should be close as possible and the shoe thickness is what regulates this.

An electromechanical cut out relay is set to just above normal battery voltage for it to come on line. It is very important that it has a good connection through the points. It is also very important that that the battery be fully charged and in good condition since that is what regulates the system voltage in any 3-brush or 5-brush system.

[steamgas]

I just checked the rpm on the generator at 1620 rpm

[steamgas]

I checked the amp draw on the field coils at 1.8 amps on a 3 brush field

[Fullraceflathead]

That sounds like plenty of rpm to see voltage output.

[steamgas]

thank you to all the ones that responded to my questions. i am at my whit's end to solve this problem.

[Joe K]

Wit's end.

Six poles. 3 are N-S, the other 3 are S-N. You should be able to trace the wiring to be sure the poles are wound correct. One reverse will make it a non-generator.

Another possibility: The movable brush - in the right spot? There might be a "dead spot between poles" since there are six.

Another possibility. Yet another Tom Wesenberg post on 5 brush powerhouse. https://fordbarn.com/forum/showthread.php?t=78015

Joe K

[rotorwrench]

The powerhouse works the same as a more simple two pole shoe design except it has three poles on one side and three poles on the other, ie north and south sides. This gives it a wider variation in the field flux that act on the armature. Since the field is controlled by it's own brush then pushing the flux distortion closer to the power output brush will increase the amount of current it will pick up off the armature. This link illustrates how all 3-brush units are configured in basic function. The only difference is that the field doesn't control the cut out on the model A designs. It comes from the armature output.
http://www.vias.org/kimberlyee/ee_31_02.html

If there is magnetism in the pole shoes with proper polarity and all the elements of the circuit are sound and functional then it will generate current. Voltage is held to the battery voltage by the way it is designed.

If any connection is weak, shorted to ground, open circuit, or the polarity of the fields is incorrect then it won't generate a proper voltage or current.

Were the field coils replaced or worked on for repairs?

[steamgas]

thank you sir for your reply. i got my information from tom wesenburg post on power house generator's. if i understand it correctly the first (1) coil from the ground screw is a ccw 103 turns #20 magnet wire, second(2) coil is a cw winding,the(3) third winding is ccw,the (4)forth winding is cw winding,the (5)fifth winding is a ccw winding and the(6) sixth coil is a cw winding. is this correct?

[rotorwrench]

Since I've not replaced the coils in one of these, I have to base the fields on theory. It should have the three south pole windings placed in direction of rotation after the power brush. The three north pole windings should be placed in direction of rotation after the ground brush. Placement may be offset somewhat. Since they could be a bit before the brushes in location of polar edges.

I don't know which coil direction of winding is north or south. Someone with experience could tell you but I can't with any certainty. If the poles are backwards, it will motor backwards. It should motor in direction of rotation. They aren't made to be motors so don't expect it to motor very fast. A person could check it with a gauss meter after polarization if you can find a simple field strength meter or maybe a compass.

[Joe K]

I haven't studied out the Powerhouse yet (I have three up on the shelves which one will eventually be used in the March 29 Pickup) but I imagine from the nom-de-plume attached it is closely aligned to its larger cousin in actual powerhouses.

Those mostly are "multi-brushed/multi-poled" - and the usual arrangement of poles is the poles are arranged in "pairs" across the centerline of the generator. The continuation of magnetic flux "continues" across the armature and the winding direction is "the same", although as the poles stand as you look at it it might go S-N-O-S-N where O is the armature.

The next pole array "around the circumference" would be N-S-O-N-S.

The last pole array would be S-N-O-S-N

I have not verified this, but I suppose this could be checked with a hikers compass. There should be enough residual magnetism to "show" without energizing the coils.

Prolly best done with the armature removed.

Joe K

[Joe K]

And "right hand rule" can be used if you can determine the direction of coil and current flow. (Keep in mind the case/ground of a Model A generator is (+) Model A frame/Battery.)

Fingers curled on the right hand. Curl and "direction" of fingers indicates the direction of flow of current. (Current goes from + to - in a DC world)

https://web.ua.es/docivis/magnet/righthand_rule.html



Joe K

[rotorwrench]

With a 3 brush DC generator, the armature should be cutting through a field of magnetism that flows across a centerline from one side to the other.

[steamgas]

trying to upload something to look at. sorry if it comes thru upside down, i don't know what i am doing but are my connections right?

[Joe K]

Originally Posted by steamgas

trying to upload something to look at. sorry if it comes thru upside down, i don't know what i am doing but are my connections right?

It is upside down, but can be read. And the connections "make sense" at least with what familiarity I have with the later Model A generator. The three brush version is not that much different connection wise - at least the parts on the casing/housing.

That is the pix I tried to describe with my N-S-O-N-S nomenclature above.

As I tried to say, the poles "alternate" around the periphery of the case.

And - I expect the windings of the associated armature have a similar orientation - hence two or four pickup brushes. I expect the two different pickup types have a corresponding armature wind.

Somewhere around here I have an early 20th century book on dynamo types/winding. "Weave winding" is one name that sticks in my head but I can't say what exactly that was all about, or specifically which field arrangement that was used against. I'll have to go find the book and see if there is some correlation to the Model A Powerhouse.

And I still have two probably functioning and complete Powerhouse generators up with parts - and another bought "cheap" as parts and because I might need.

Joe K

[Kurt in NJ]

here is a original 5 brush, the 2 ground brushes are at the mounting struts
the buss bar connecting the 2 opposite brushes goes to the output post
the field brush is near the field ground and wire off the fields
When you tested the armature on the growler you said you went bar to bar —- what were you measuring? —- i would be looking for amperage to prove the windings are making power.
I used to rebuild a lot of starters,alternator,generator, I had a big iron (600watt), it would get the commutator bars to soldering temperature quickly, no heat soak into the windings getting the connection to soldering temperature, I would resolder every armature as insurance