What's new
What's new

NON WORKING EXCITER. I need some info 10ee 1945 MG

lectrician1

Hot Rolled
Joined
Mar 6, 2012
Location
Las Vegas
my 10ee exciter arrived with a non working exciter

I am trying to get it working. It seems like it was not wired according to the schematic and the replacement brushes were never seated.

I have a few questions.

1. there is a variable resistor in series with the shunt field. where should the resistor physically be located?
mine was bolted to the outside of the exciter casing with the wires running through the opening.
it didn't look like that was the factory mounting location
should it be mounted inside the exciter?
More importantly to how many ohms should the resistor be set?
i think mine goes from zero to 200 ohms.
2.it looks like there where replacement brushes that were never seated
the replacement brushes did not have a wire connected to the back. it looks like the wire had been removed
and they were relying on the spring for connectivity
should i rely on the spring or solder a wire on there?

3. it looks like both the series field and the shunt field are wound around the same core
so on both sides on the exciter there is a winding. each winding has two wires coming out of each side.
there is a heavier gauge wire and a lighter gauge wire.
i am trying to figure which wire goes to which field
i assume that the heavier wire is the series field and the lighter wire is the shunt field
can anyone confirm which wire is for which field?

Thanks in advance
Rich

here you can see how my resistor is mounted
FD65C0EA-81F5-4A85-84F2-40D16E3CB073.jpg
 
Here is a very good discussion about the exciter:
From the sticky's above: 10EE - No Exciter Voltage

The original location for the resistor is in the bell of the generator, just below the exciter. I believe that the resistor is mounted in the generator bell because there is cooling circulation through the generator and AC motor driving the generators.

In the 'Sticky' discussion, Cal spells out the normal ohm readings and procedure.

DualValve
 
Above link is VERY helpful. I’ve had to refer to it more than once. On mine, I finally took the exciter apart and turned the commutator down past burns/divots. Carefully filed the mica and seated the brushes, and now is working great.
 
i got the exciter WORKING! HOW EXCITING!

I seated the brushes and I had to rewire it. previous owner wired it wrong.
I mounted the resistor right above the sheave in the front of the exciter

right now it is sitting on my bench. but i got it spinning close to operating speed maybe 3k rpm and it was producing 101v dc.
tomorrow i will mount it in machine and tweak it
thanks for your assistance
Rich
 
i got the exciter mounted but it is only producing 105v dc. variable resistor is at its lowest setting of about 2.5ohms.

i had some trouble starting the spindle at the highest RPM 2500.

machine ran better with the 115vdc power supply.
 
That's definitely not the original resistor. Take it out of the circuit and see if the voltage improves.

The problem starting at 2500 RPM is because your FA relay isn't working.

Cal
 
i shorted the resistor and the voltage actually went down to 102vdc from 105
i also manually pressed the FA relay and spindle still did not start
 
I wouldn't expect the voltage to go down when you jumper around the resistor. You might check the field current.

I assume that you checked the resistances of the windings.

It's possible that the brushes aren't correctly timed. Look at the brush ring and see if you can find the index mark, then look for a witness mark on the hub of the spider. Later model exciters have the index mark at about 9 O'clock, when looking at the pulley end of the exciter:

IMG_9933.jpg

Cal
 
I seated both brushes. they were never seated. i assume that is why the exciter wasn't working when i got the machine. i also had to redo all the internal connections.
is it possible i made a mistake with the polarity of the field windings that is causing the low voltage?
 
exciter VS power supply

another weird thing. with the dc power supply, the lathe would run/start flawlessly at all speeds even if the supply was as low as 90v dc.
Now with the exciter at 105v, the spindle has trouble starting at 2500rpm. When trying to start at 2500 rpm, the gen would sound taxed, for a second then the forward contactor drops out. another second and the contactor pulls in and the gen try's to start then the contactor falls out again. this keeps happening. on off on off.
happens worse when in reverse
 
i had to guess about the internal connections and which wires went to which windings and the polarity.
i saw in an old post that the armature connection to the series winding had to be on the right side brush when looking from the front.
i saw the post after i installed everything and i am not sure i did it that way.
 
another weird thing. with the dc power supply, the lathe would run/start flawlessly at all speeds even if the supply was as low as 90v dc.
Now with the exciter at 105v, the spindle has trouble starting at 2500rpm. When trying to start at 2500 rpm, the gen would sound taxed, for a second then the forward contactor drops out. another second and the contactor pulls in and the gen try's to start then the contactor falls out again. this keeps happening. on off on off.
happens worse when in reverse
Does that only happen at high RPMs? If so, it sounds like the exciter voltage is dropping enough that the contactor is opening. If it's now happening at all speeds, it's an issue with the hold in circuit.

Cal
 
The exciter is designed to put out a constant 115 VDC at varying loads. The series field, in series (as the name implies) with the exciter's armature, increases the field and therefore the output of the exciter when the load increases. The shunt field, which has the adjustable series resistor, must operate in opposition to the series field. As the voltage increases, current through the shunt field increases, opposing the series field and DECREASING the exciter's output to keep the voltage where it belongs. That's is why a jumper across the resistor, which increases the series field current, DECREASED the exciter's output. Try increasing the series resistance.

Also note that if the polarity of the shunt and series fields aren't correct, they will work to push the output voltage in wrong direction as load changes. You say you guessed at how to connect the leads; how many leads are we talking about?

Cal
 
there are 8wires altogether.
one winding on either side of the armature
two wires coming out of each side of each winding.

so each winding has two wires coming out of the top and two wires coming out of the bottom

one of the wires is heavier like 16 awg
one wire is lighter like 18awg

i figured the heavy wire was the series field

the lighter wire was the shunt field

so four series field wires and 4 shunt

I tied the two windings together in series
so the series wire from the top left winding spliced to the series wire from the top right winding
same for the shunt wires

i also measured the resistance of each winding pair and they matched. iirc 530ohms was one set dont remember which

now there where 4 wires remaining
one heavy, one light coming out the bottom of each winding

i brought one heavy to the brush
i spliced the other heavy to the light wire of the shunt field that became E1

the other light wire went to the resistor

the other side of the resistor became E2
and was connected to the other brush

i tried to follow the schematic but wasn't sure about polarity
i just put it together and ran it to see if it would produce DC voltage

it produced voltage while running it on the workbench but it was only about 103v
i figured i wasn't spinning it fast enough so i installed it in the machine

tomorrow i will take it apart and switch the polarity
so the two windings oppose one another
the way i wired it i dont think the windings are opposing one another

i tried increasing the resistance all the way and the output just went lower
it went down to 24v
 








 
Back
Top