New armature, discolored commutator?

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Model T Ford Forum: Forum 2012: New armature, discolored commutator?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Monday, September 03, 2012 - 10:50 pm:

so just installed a new rewind in my generator. so far its working good. charging at a good rate.

i found the null point as per Ford instructions

i sanded the brushes to the commutator

the thing is the commutator is turning slightly purpleish, and has black deposits on it.

the reason i replaced it is because i had a wiring failure and the armature over heated. the wires coming off the brushes turned somwhat yellow in color as opposed to their natural copper color.

the field windings were replaced recently but i used an old armature that was iffy to begin with.

any thoughts? is it the brushes possibly?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Tuesday, September 04, 2012 - 02:12 am:

well i guess ill just have to wait for Ron


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Tuesday, September 04, 2012 - 06:34 am:

What do you mean "charging at a good rate"? You don't want it to charge more than about 5 amps at cruise speed with the headlights off. It you show 1 amp charging with the headlights on you are good. More than that is going to melt the generator.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ron Patterson-Nicholasville, Kentucky on Tuesday, September 04, 2012 - 10:05 am:

Matthew
I cannot be sure, but two things you say bother me. A discolored commutator is not normal and indicates the generator is running very hot.
Some black on the commutator is normal, but if it is excessive it is indicative of poorly undercut Mica segments.
You will have to get to the bottom of these problems or you will eventually destroy the generator.
Ron the Coilman


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Tuesday, September 04, 2012 - 01:30 pm:

thats what im afraid of. the slots appeared to be well undercut, but if i take it apart again (likely) i will check.

i drive at night so i set the gen up to charge about 2 amps with the lights on.

i wonder if possibly the brushes still needed to wear in, and due to the low amount of contact heat was created because of resistance? or possibly the brushes have been comprimised from when the genny took a dive?

i think i will start by cleaning the comm. and replacing the brushes. and do a thorough check of all internal wiring connections.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Tuesday, September 04, 2012 - 01:43 pm:

heres a pic of the commutator


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Tuesday, September 04, 2012 - 02:24 pm:

http://www.remco1.com/Commutator_brochure.pdf

just read this great article, looks like i might have run the generator to soon without the brushes fully seating, which will cause arcing.

it also talks about brush spring pressure, i wonder if when the generator got hot the springs lost temper. ive got some good springs ill try as well.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ken Kopsky, Lytle TX on Tuesday, September 04, 2012 - 05:58 pm:

If the generator got hot enough to de-temper the springs, you'd have solder all over the place too. It looks like the commutator is worn uneven causing poor brush contact and bounce. I'm not a proponent of cutting the commutator un-necessarily but that one needs it. The wear shown by the arrow below indicates a ridge. This ridge can cause the rear of the brush to lift as the armature moves back and forth.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Tuesday, September 04, 2012 - 06:19 pm:

well im putting back together as we speak.

the commutator has been turned, i thought there was a ridge too, but i just cleaned it up and its still true ill post a pic of it cleaned, there was some junk in the mica so i cleaned it out,

the weak brush springs got hot when the generator burned up, this is a different armature. i just replaced them and the "new" ones are much stronger, plus it looked like i may have put the brushes in backwards and the spring was not alined right. im sanding the brushes to the commutator right now.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Tuesday, September 04, 2012 - 07:05 pm:

well i just let it sit and run on the bench with the battery charger hooked to it, and its getting a little bit of color.

this again with old brushes sanded to fit the comm.

a friend of mine recomended i throw it on a growler to make sure its not the armature that is the problem. im going to try and scare up some new brushes.


Top of pagePrevious messageNext messageBottom of page Link to this message  By JohnH on Tuesday, September 04, 2012 - 08:11 pm:

That sort of charge rate is way more than I'd ever be comfortable with, and this obsession with high charge rates seems to be quite common.
I drive at night too, but have a charge rate of 5A with the lights off. So, the ammeter shows discharge with the lights on. But, I'm going to have to be driving with the lights on for almost 10 hours before my 100Ah battery goes flat - and no one I knows drives a T for that many hours at night.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Tuesday, September 04, 2012 - 08:30 pm:

the problem with that is at 5 amps you will cook your battery, and at a charge rate of 5 amps, your probably discharging at 3-5 amps with your headlamps on, your headlight probably wont stay bright for too long and its not good for your battery.

Ford recommends a charge of 12 amps without headlights on, a T generator is perfctly capable of doing so.

currently without my healights on im at about 9-10 amps which places me at about +1-2 amps with lights and tail. which is enough to maintain your battery and acount for idle time when you are discharging around 5 amps.

at least this is the case with my headlights im running 32-50cp's which may draw more than 21-21cp's however the difference between bright and dim is un noticable at the ammeter

if you hardly ever drive at night then set your generator to run in the day with no lights on, and if you have to, adjust it when the sun goes down. this last sunday i drove about 65 miles at night, I like my battery to stay charged.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Tuesday, September 04, 2012 - 08:32 pm:

i should note that at this setting i run with my headlights on day or night.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Stitt-Southern Oregon on Tuesday, September 04, 2012 - 09:21 pm:

Perhaps John at Fun Projects would consider making a daylight control Module. It will give you a safety edge and make the filaments last a bit longer and for that matter help your generator.

I tend to no longer address generator issues on this forum but should you turn and undercut your armature you can buy or make a chamfering tool used to chamfer each bar.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Matthew David Maiers on Tuesday, September 04, 2012 - 09:25 pm:

in the last cutout discussion somone said in the early ford designs one of the ideas was to have two generator settings for lights on or lights off.

i used the tip of a needle file to clean the bars. before i used a dental tool.


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