Hello! Log in or Register   |  Help  |  Donate  |  Buy Shirts New!  See all banner ads | Advertise on TheSamba.com  
TheSamba.com
 
Is this generator armature bad, can someone confirm? W/ PICTURE
Page: 1, 2  Next
Forum Index -> Performance/Engines/Transmissions Share: Facebook Twitter
Reply to topic
Print View
Quick sort: Show newest posts on top | Show oldest posts on top View previous topic :: View next topic  
Author Message
evanfrucht
Samba Member


Joined: July 24, 2016
Posts: 1431
Location: Laurel Canyon, CA
evanfrucht is offline 

PostPosted: Sat Jul 25, 2020 1:42 pm    Post subject: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

Picture speaks for itself

I'm kinda bummed I hoped to rebuild this 67 only generator.

Everywhere it says there should be no continuity from commutator to shaft. And if there is any reading, it's junk... IS THAT CORRECT?

How does this even happen, where does it normally short on the shaft. Is it possible to somehow fix it ? There is no physical damage that I can detect anywhere. How did Bosch isolate it from the shaft when they make it ?

Image may have been reduced in size. Click image to view fullscreen.

_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )
Back to top
View user's profile Send private message Gallery Classifieds Feedback
evanfrucht
Samba Member


Joined: July 24, 2016
Posts: 1431
Location: Laurel Canyon, CA
evanfrucht is offline 

PostPosted: Sat Jul 25, 2020 1:46 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

That is 2.4 MILI-OHMS or 0.0024 OHMS (little m before the ohms symbol.) I have an new multimeter that sets the measuring range automatically. Is that reading so low that it's fine/normal? I'm lost here.
_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Big Al
Samba Member


Joined: June 14, 2014
Posts: 178
Location: Tucson, AZ
Big Al is offline 

PostPosted: Sat Jul 25, 2020 1:57 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

Your reading continuity between the shaft and windings. That just one test and that one is good.

The proper way to test that armature is with a growler, something most don't have.

https://en.wikipedia.org/wiki/Growler_%28electrical_device%29

You need to find a shop with a growler or check in the generator.

Al
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
evanfrucht
Samba Member


Joined: July 24, 2016
Posts: 1431
Location: Laurel Canyon, CA
evanfrucht is offline 

PostPosted: Sat Jul 25, 2020 2:08 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

Ok, so that one test is good? I was unsure if .002 amps counted as "no continuity."

All the other cave man multimeter tests check out.

Thats part of why I was confused. I know these tests are not exactly the proper way to test ( growler )

Unfortunately I don't have a growler
_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )


Last edited by evanfrucht on Sat Jul 25, 2020 2:18 pm; edited 1 time in total
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Dale M.
Samba Member


Joined: April 12, 2006
Posts: 19537
Location: Just a tiny bit west of Yosemite Valley
Dale M. is offline 

PostPosted: Sat Jul 25, 2020 2:08 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

evanfrucht wrote:
That is 2.4 MILI-OHMS or 0.0024 OHMS (little m before the ohms symbol.) I have an new multimeter that sets the measuring range automatically. Is that reading so low that it's fine/normal? I'm lost here.


Umm it meg ohms, meaning "million" ....2.54 million ohms...

Dale
_________________
“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.

"Kellison Sand Piper Roadster" For Street & Show.
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ...
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Big Al
Samba Member


Joined: June 14, 2014
Posts: 178
Location: Tucson, AZ
Big Al is offline 

PostPosted: Sat Jul 25, 2020 2:20 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

Let me try to answer your question. You are seeing a very tiny current path between the windings and the shaft. 2.54 million Ohms is for practical purposes nothing. You usually make that test with 120 volts and a 15 Watt light bulb. If you have an old AC cord you can make a tester. Just be careful when you use it, I do it all the time and am still alive:)

Separate the wires and hook a light bulb between one wire and the commutator. The other to the shaft. Any wattage regular light bulb will work. You can even use a table lamp, just hook one wire from the suicide cord, that what I call mine, to the shaft. The other to one side of the lamp's plug, clip lead from the other side to the commutator. If you connect it right the light bulb will light up if you short the wires together.

Keep one hand in your pocket so we don't hear about it:)

Not exact but you can get the idea.

https://www.youtube.com/watch?v=zrbxpUfa27U

You would place the armature between his two test posts.

The reason you use 120 Volts and not a much safer 12 Volts is you're testing the quality of the insulation between the windings and the metal of the armature. The higher voltage puts more stress on the insulation.

Al
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
evanfrucht
Samba Member


Joined: July 24, 2016
Posts: 1431
Location: Laurel Canyon, CA
evanfrucht is offline 

PostPosted: Sat Jul 25, 2020 2:21 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

Dale M. wrote:
evanfrucht wrote:
That is 2.4 MILI-OHMS or 0.0024 OHMS (little m before the ohms symbol.) I have an new multimeter that sets the measuring range automatically. Is that reading so low that it's fine/normal? I'm lost here.


Umm it meg ohms, meaning "million" ....2.54 million ohms...

Dale


That just my incorrect vocabulary...

I meant to say milliohms

1 milliohm = .001 ohms... if my research is correct
_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )
Back to top
View user's profile Send private message Gallery Classifieds Feedback
evanfrucht
Samba Member


Joined: July 24, 2016
Posts: 1431
Location: Laurel Canyon, CA
evanfrucht is offline 

PostPosted: Sat Jul 25, 2020 2:22 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

Big Al wrote:
Let me try to answer your question. You are seeing a very tiny current path between the windings and the shaft. 2.54 million Ohms is for practical purposes nothing. You usually make that test with 120 volts and a 15 Watt light bulb. If you have an old AC cord you can make a tester. Just be careful when you use it, I do it all the time and am still alive:)

Separate the wires and hook a light bulb between one wire and the commutator. The other to the shaft. Any wattage regular light bulb will work. You can even use a table lamp, just hook one wire from the suicide cord, that what I call mine, to the shaft. The other to one side of the lamp's plug, clip lead from the other side to the commutator. If you connect it right the light bulb will light up if you short the wires together.

Keep one hand in your pocket so we don't hear about it:)

Not exact but you can get the idea.

https://www.youtube.com/watch?v=zrbxpUfa27U

You would place the armature between his two test posts.

The reason you use 120 Volts and not a much safer 12 Volts is you're testing the quality of the insulation between the windings and the metal of the armature. The higher voltage puts more stress on the insulation.

Al


That just basically answered all my questions and cleared it up for me. Thank you!!!

I simply have disassembled it and soda blasted all parts. I plan to replace brushes and bearings. I stuck it in my drill press and cleaned up the commutator surface with a fine flat file followed by some 400 grit sandapaper. Its still well above 32.9 mm in diamter which as far as I know is the wear limit spec. Mine after cleaning up is about 35mm

Basically I dont have much invested so I plan to test as well as I can with what I have, and then test if its working with an electric drill once assembled.
_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Big Al
Samba Member


Joined: June 14, 2014
Posts: 178
Location: Tucson, AZ
Big Al is offline 

PostPosted: Sat Jul 25, 2020 2:31 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

Big Al wrote:
Your reading continuity between the shaft and windings. That just one test and that one is good.

The proper way to test that armature is with a growler, something most don't have.

https://en.wikipedia.org/wiki/Growler_%28electrical_device%29

You need to find a shop with a growler or check in the generator.

Al


If you looked at the picture on Wikipedia of a growler, the big light bulb is for the continuity tests we're talking about.

Al
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
Dale M.
Samba Member


Joined: April 12, 2006
Posts: 19537
Location: Just a tiny bit west of Yosemite Valley
Dale M. is offline 

PostPosted: Sat Jul 25, 2020 2:36 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

evanfrucht wrote:
Dale M. wrote:
evanfrucht wrote:
That is 2.4 MILI-OHMS or 0.0024 OHMS (little m before the ohms symbol.) I have an new multimeter that sets the measuring range automatically. Is that reading so low that it's fine/normal? I'm lost here.


Umm it meg ohms, meaning "million" ....2.54 million ohms...

Dale


That just my incorrect vocabulary...

I meant to say milliohms


1 milliohm = .001 ohms... if my research is correct


You are at the wrong end of spectrum Milli is not million, ... You are measuring millions of ohms....

One meg = 1,000,000.000 Ohms...

Your meter is telling you 2,540,000.000 ohms...

Note decimal point(s)....Milli would be to right of decimal point

Dale
_________________
“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.

"Kellison Sand Piper Roadster" For Street & Show.
============================================================
All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ...
Back to top
View user's profile Send private message Gallery Classifieds Feedback
EVfun
Samba Member


Joined: April 01, 2012
Posts: 4284
Location: Seattle
EVfun is offline 

PostPosted: Sat Jul 25, 2020 2:54 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

That meter wasn't displaying mΩ, it was displaying MΩ.
Not millionths of an ohm but millions of ohms.

Not many digital multimeters can measure milliohms. Almost all of them can measure megohms. That armature is fine.
_________________
Wildthings wrote:
As a general rule, cheap parts are the most expensive parts you can buy.


Last edited by EVfun on Sat Jul 25, 2020 3:17 pm; edited 1 time in total
Back to top
View user's profile Send private message Gallery Classifieds Feedback
evanfrucht
Samba Member


Joined: July 24, 2016
Posts: 1431
Location: Laurel Canyon, CA
evanfrucht is offline 

PostPosted: Sat Jul 25, 2020 3:02 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

Ok now I get that. I didn't realize the capitalization meant anything

I'm even more confused now as to whether the armature passed that test?
_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Krochus
Samba Member


Joined: January 01, 2017
Posts: 892
Location: NW Arkansas
Krochus is offline 

PostPosted: Sat Jul 25, 2020 3:08 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

2 megaohms from the 9 volts of a meter is actually pretty low in the grand scheme of things for resistance to ground. Hand held ohmmeters really aren’t well suited to checking insulation condition.

For example our pass criteria at work for dc armatures is 100megaohms at 500v on a dc megaohmmeter

Wash it with dawn soap and water. Then bake it at 220 degrees vertically com end up for 6 hours. It’ll probably read infinity afterwards

Now if you really want to test it check resistance bar to bar then work out the imbalance percentage
_________________
1970 Turbo Baja Bug Turbaja 2165 t3/t4 Speeduino sequential EFI LS3 coil on plug ignition

1965 Chevy c30, Microsquirt turbo aluminum 5.3/nv4500
Back to top
View user's profile Send private message Gallery Classifieds Feedback
evanfrucht
Samba Member


Joined: July 24, 2016
Posts: 1431
Location: Laurel Canyon, CA
evanfrucht is offline 

PostPosted: Sat Jul 25, 2020 3:14 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

Big Al wrote:
Let me try to answer your question. You are seeing a very tiny current path between the windings and the shaft. 2.54 million Ohms is for practical purposes nothing. You usually make that test with 120 volts and a 15 Watt light bulb. If you have an old AC cord you can make a tester. Just be careful when you use it, I do it all the time and am still alive:)

Separate the wires and hook a light bulb between one wire and the commutator. The other to the shaft. Any wattage regular light bulb will work. You can even use a table lamp, just hook one wire from the suicide cord, that what I call mine, to the shaft. The other to one side of the lamp's plug, clip lead from the other side to the commutator. If you connect it right the light bulb will light up if you short the wires together.

Keep one hand in your pocket so we don't hear about it:)

Not exact but you can get the idea.

https://www.youtube.com/watch?v=zrbxpUfa27U

You would place the armature between his two test posts.

The reason you use 120 Volts and not a much safer 12 Volts is you're testing the quality of the insulation between the windings and the metal of the armature. The higher voltage puts more stress on the insulation.

Al


I'm going to forget that fancy multimeter for now and use (make) the correct tool for the job... will get back with results. Thanks
_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )
Back to top
View user's profile Send private message Gallery Classifieds Feedback
earthquake
Samba Member


Joined: January 10, 2008
Posts: 3585
Location: SANDY VALLEY, NEVADA
earthquake is offline 

PostPosted: Sat Jul 25, 2020 3:20 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

Find a electric motor repair shop near you, they should be able to test it for you.
I have never seen a EM repair shop that does not have a growler.

eQ
_________________
74 CLASS 11 LOOK-A-LIKE
69 DUNE BUGGY
79 INTERNATIONAL SCOUT II
05 SCION XB SERIES RELEASE 2[#437]

Kelly J. Nolte 3/20/53 - 11/6/08
http://www.rememberingkelly.com/

DEATH TO CHINGERS!
[From a military recruitment poster in the novel "The Stainless Steel Rat" By Harry Harrison]
Back to top
View user's profile Send private message Gallery Classifieds Feedback
EVfun
Samba Member


Joined: April 01, 2012
Posts: 4284
Location: Seattle
EVfun is offline 

PostPosted: Sat Jul 25, 2020 3:24 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

That is only 6 microamps of current at 15 volts. That is fine in a brushed DC motor or generator. I see no cause for concern yet. Next, don't scratch up those commutator segments but check from one to the next around the commutator. Your looking for an open winding. That would also fail the commutator.

To out 6 microamps into perspective a dim tiny LED is drawing around 2000 microamps. You car battery is self-discharging at around 1000 microamps if it's in nearly new condition.
_________________
Wildthings wrote:
As a general rule, cheap parts are the most expensive parts you can buy.


Last edited by EVfun on Sat Jul 25, 2020 3:31 pm; edited 1 time in total
Back to top
View user's profile Send private message Gallery Classifieds Feedback
evanfrucht
Samba Member


Joined: July 24, 2016
Posts: 1431
Location: Laurel Canyon, CA
evanfrucht is offline 

PostPosted: Sat Jul 25, 2020 3:26 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

earthquake wrote:
Find a electric motor repair shop near you, they should be able to test it for you.
I have never seen a EM repair shop that does not have a growler.

eQ


The problem is I dont really have any budget for this so I'm trying to avoid paying a shop. I also dont really want to go driving around searching for someone who will test it for free.
_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Big Al
Samba Member


Joined: June 14, 2014
Posts: 178
Location: Tucson, AZ
Big Al is offline 

PostPosted: Sat Jul 25, 2020 3:45 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

https://www.youtube.com/watch?v=JUeeuDrIKVQ

This should help.

Al
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
evanfrucht
Samba Member


Joined: July 24, 2016
Posts: 1431
Location: Laurel Canyon, CA
evanfrucht is offline 

PostPosted: Sat Jul 25, 2020 3:45 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

EVfun wrote:
That is only 6 microamps of current at 15 volts. That is fine in a brushed DC motor or generator. I see no cause for concern yet. Next, don't scratch up those commutator segments but check from one to the next around the commutator. Your looking for an open winding. That would also fail the commutator.

To out 6 microamps into perspective a dim tiny LED is drawing around 2000 microamps. You car battery is self-discharging at around 1000 microamps if it's in nearly new condition.


I did 2 other tests. One where you check each of the commutator bars that are 180 degress opposite each other. And one where you check the ones next each other.

180 test showed 0.2 ohms all around

The other test showed mostly 0.0 ohms bug some 0.1 ohm
_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )
Back to top
View user's profile Send private message Gallery Classifieds Feedback
evanfrucht
Samba Member


Joined: July 24, 2016
Posts: 1431
Location: Laurel Canyon, CA
evanfrucht is offline 

PostPosted: Sat Jul 25, 2020 3:51 pm    Post subject: Re: Is this generator armature bad, can someone confirm? W/ PICTURE Reply with quote

Big Al wrote:
https://www.youtube.com/watch?v=JUeeuDrIKVQ

This should help.

Al


Its not a charging issue im having or ever had. This generator probabaly never got to point of actually failing. I think it was just on an engine that seized....

Heres the quick story

I'm in the middle of building a 2180 to pop into my 1967 bug.This generator came with the frozen engine that I bought for the case and other parts for my build. ( very strange coincidence because its a 1971 engine )

I thought it would be neat to rebuild it and use it on the engine since my car is a mostly original 1967 bug.

I have no idea if it worked when that engine was pulled becuase i bought the engine as a core BUT I would guess it was in fine working order since I found the engine to have failed from a seized/spun rod bearing. It doesnt look like there was much brush wear to the commutator, when I compare mine to the specs and pictures of other ones people have deemed usable.


On a side note i actually have another 67 only generator that was on the original engine for my car ( i have the original matching numbers engine stored away ) while i was still driving around the original rngine that generaror stopped charging so I just bought a rebuilt bosch at the time for quick fix
_________________
1967 Bug ( the daily rod )
1964 Fury Wagon ( the pavement shredder )


Last edited by evanfrucht on Sat Jul 25, 2020 4:01 pm; edited 1 time in total
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Display posts from previous:   
Reply to topic    Forum Index -> Performance/Engines/Transmissions All times are Mountain Standard Time/Pacific Daylight Savings Time
Page: 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

About | Help! | Advertise | Donate | Premium Membership | Privacy/Terms of Use | Contact Us | Site Map
Copyright © 1996-2020, Everett Barnes. All Rights Reserved.
Not affiliated with or sponsored by Volkswagen of America | Forum powered by phpBB