Antique Engines and Old Iron
[Home] - [HELP] - [Forums] - [Library] - [Photo Gallery] - [Groups] - [Classified Ads] - [Subscribe] - [Links] - [Books] - [Sponsors] -

Go Back   SmokStak > SmokStak® Vintage Electrical Equipment > Generators & Electric Motors General Discussion > Military MEP and Aircraft Gen-Sets
Forgot Password? Join Us!

Notices

Military MEP and Aircraft Gen-Sets MEP Mobile Electric Power, APU Auxiliary Power Unit and other military surplus generators.

Military MEP and Aircraft Gen-Sets

PE-75 Frame Ground


this thread has 9 replies and has been viewed 789 times

Reply
 
Thread Tools Display Modes
  #1  
Old 08-08-2017, 07:11:23 PM
Myers Myers is online now
Registered
 
Join Date: Nov 2013
Location: Fayetteville, North Carolina, United States
Posts: 39
Thanks: 1
Thanked 29 Times in 12 Posts
Default PE-75 Frame Ground

I am restoring a 1944 PE-75-U. While it is very complete and original, it happens to be missing the frame ground cable. If anyone has an original ground cable (it is a 3-way wire harness that connects the alternator, engine, and frame. It attaches to the top of the frame with a #8-32 screw), could you please post some close up photos and measurements? I need to make one for my generator, and there aren't any detailed photos of the cable, nor is it depicted in TM-11-900.

This is the best photo I can find.

Reply With Quote
Sponsored Links
  #2  
Old 08-13-2017, 11:34:11 PM
Military Dave Military Dave is offline
Registered-I
 
Join Date: Feb 2011
Location: Evergreen State, USA
Posts: 128
Thanks: 8
Thanked 25 Times in 16 Posts
Default Re: PE-75 Frame Ground

Hey Myers, that is an excellent request. I didn't know that this Gennie required such a harness. I have the same exact assembly, restored, but don't have the ground harness.
I hope I haven't been putting my life at risk, because I run my Gen. every three to six weeks to light up my garage and to keep it healthy.
By the way, did your P.E. 75 have all the data plates? If so, is it an "AA", "AB", "AC" or "AD"?
Reply With Quote
  #3  
Old 09-09-2017, 10:29:00 PM
Myers Myers is online now
Registered
 
Join Date: Nov 2013
Location: Fayetteville, North Carolina, United States
Posts: 39
Thanks: 1
Thanked 29 Times in 12 Posts
Default Re: PE-75 Frame Ground

Hi Dave,

Mine has all tags and identification. It is a May 1944 PE-75-U with a ZZ engine. The frame ground isn't critical, you shouldn't have any issues. The vast majority of these have lost theirs over the years and I don't think anyone has burned down a shop yet.

I am still looking for someone to post a photo/dimensions of an original frame ground cable. Any help would be appreciated.



Here is another photo of the ground cable, this on is on a PE-75-T, whereas the first photo features a 75-U.
Reply With Quote
  #4  
Old 09-11-2017, 12:35:22 AM
Military Dave Military Dave is offline
Registered-I
 
Join Date: Feb 2011
Location: Evergreen State, USA
Posts: 128
Thanks: 8
Thanked 25 Times in 16 Posts
Default Re: PE-75 Frame Ground

Thanks Myers for that photo. I have been able work on many W.W. 2 vehicles over the past 22 years and in the T.M.'s, the ground harness is referred to as a "bonding strap". Now that I have seen what you are talking about, I understand that it just provides ground continuity to the entire assembly.
I always wondered what the small flat head screw on the skid was for.
...........And because of your photo, I can easily build one that looks like the one on your P.E. 75.
Thanks again. D.
Reply With Quote
  #5  
Old 09-11-2017, 11:32:32 AM
Myers Myers is online now
Registered
 
Join Date: Nov 2013
Location: Fayetteville, North Carolina, United States
Posts: 39
Thanks: 1
Thanked 29 Times in 12 Posts
Default Re: PE-75 Frame Ground

Hi Dave,

Yes, it is simply a bond strap. It is listed in the under "d Skid Base" if you want to see it in TM-11-900.

"3H4575T/C10 Cable... Ground... Grounds generator and engine to frame."

If you need the correct slotted #10-32-1/4 machine screw for the frame, I bought a bag of 100 of them.

I've made a harness out of 1/4" tinned flat braid, it it looks spot on. However, I like to avoid "close enough", so I'm still hoping to get the measurements from an original cable. I will admit, I am a bit obsessive over the fine details, but everyone has to have a hobby, right
Reply With Quote
The Following User Says Thank You to Myers For This Post:
  #6  
Old 09-12-2017, 01:43:52 AM
Vanman Vanman is offline
Subscriber
 
Join Date: Aug 2011
Location: Mission Viejo, California
Posts: 3,277
Thanks: 4,031
Thanked 1,363 Times in 911 Posts
Default Re: PE-75 Frame Ground

I wasn't sure if I had the ground strap with my beat up set (boxes of parts at the moment), and indeed for awhile I was convinced that I didn't have it.

I have the parts fairly well sorted. The engine parts are all in one box, with small parts and hardware in Ziploc bags. The generator field frame and end bells are in another box, and the armature is in an adjacent box.

I thought that was it, until I stumbled across *another* box labeled "Leland Generator Parts" This one had all kinds of other stuff from the generator, again with the small parts in the bags, and low and behold, there was the strap, in one of the bags.

My Stupid Smartphone is being Stupid, so I'm having trouble with pictures tonight. It uploaded the ones I had already deleted to the computer, did NOT upload the ones I wanted, and then said that "there was a problem". Yeah. No kidding.

I'm trying to fool the damned thing into emailing them to myself now.

OK, AFTER the email trick the damned thing finally decides to move the right photos to the computer. Can you tell I don't have much patience for junk?!?

It appears that the ground strap is 8-1/2" long, center to center of the bolt holes in the ring terminals, if it were laid out flat.

The ring terminals appear to be copper. After the crimp, they were soldered to the braid. Inside diameter of the holes are just shy of 5/16", OD is just shy of 11/16", maybe 21/32". Might have been 5/8" originally, and flattened out a bit larger. There definitely was a lock washer on one of them, that took a bite.

The braid behaves like copper. It's hard to tell if it was originally just bare copper, or if it was made up of tinned strands- it's really dirty and tarnished. The back almost looks to me like it was bare copper. The width of the braid is all over the map lol. But I'd say that it had been 1/4" originally.

The "T" junction appears to have been made by folding the end over the straight section, smashing it down flat, and soldering it.
Attached Thumbnails
Click image for larger version

Name:	IMG_20170911_215526783.jpg
Views:	28
Size:	168.2 KB
ID:	290957   Click image for larger version

Name:	IMG_20170911_215540740.jpg
Views:	28
Size:	116.4 KB
ID:	290958   Click image for larger version

Name:	IMG_20170911_215604624.jpg
Views:	30
Size:	79.4 KB
ID:	290959   Click image for larger version

Name:	IMG_20170911_215550531.jpg
Views:	29
Size:	103.5 KB
ID:	290960  

Reply With Quote
  #7  
Old 09-12-2017, 01:56:58 AM
Vanman Vanman is offline
Subscriber
 
Join Date: Aug 2011
Location: Mission Viejo, California
Posts: 3,277
Thanks: 4,031
Thanked 1,363 Times in 911 Posts
Default Re: PE-75 Frame Ground

The third ring terminal- that would have connected to the frame- is broken off on mine (along with LOTS of other stuff LOL). It's broken right at the ring. Accounting for that, that section would have been just over 3" from the far side of the straight section to the center of the ring, maybe 3-1/16" or 3-1/8".

I would have guessed that all three ring terminals were the same, but one of mine is broken off, another heavily distorted, and the good one twisted up a bit. On careful inspection, the two at the ends of the straight section are the same, but the broken one is different. I suppose I have that ring, still under it's bolt, still on the frame.

You can see from the remnants of the third one that it actually had two parts crimped onto the braid. The others only have one crimp area. All were soldered after crimping.
Attached Thumbnails
Click image for larger version

Name:	IMG_20170911_215646810.jpg
Views:	31
Size:	161.9 KB
ID:	290961   Click image for larger version

Name:	IMG_20170911_215619414.jpg
Views:	23
Size:	111.5 KB
ID:	290962  
Reply With Quote
  #8  
Old 09-13-2017, 01:35:40 AM
Vanman Vanman is offline
Subscriber
 
Join Date: Aug 2011
Location: Mission Viejo, California
Posts: 3,277
Thanks: 4,031
Thanked 1,363 Times in 911 Posts
Default Re: PE-75 Frame Ground

I thought that I would add that the "T" junction is NOT in center of the straight section. It's right about 5" from the center of the engine ring terminal, and 3-1/2" from the generator.
Reply With Quote
  #9  
Old 09-14-2017, 10:43:41 AM
Myers Myers is online now
Registered
 
Join Date: Nov 2013
Location: Fayetteville, North Carolina, United States
Posts: 39
Thanks: 1
Thanked 29 Times in 12 Posts
Default Re: PE-75 Frame Ground

Hi Keith,

Absolutely perfect, you went far above and beyond with this one!

My estimated sizes were pretty close, but nothing beats having the actual dimensions. And now anyone with a PE-75 can make an accurate replacement for these very elusive grounding cables.

Thanks again!!
Reply With Quote
The Following User Says Thank You to Myers For This Post:
  #10  
Old 09-15-2017, 11:23:13 PM
Military Dave Military Dave is offline
Registered-I
 
Join Date: Feb 2011
Location: Evergreen State, USA
Posts: 128
Thanks: 8
Thanked 25 Times in 16 Posts
Default Re: PE-75 Frame Ground

Ben, I sent you a P.M. to contact me via my email address, which I included. Our hobby of tinkering with old machines like these MUST have the fine attention to detail that they deserve, especially because they are so simple. It is best to restore it "right" and holding out for a correct ground strap or muffler is not above and beyond the call of duty, it is the required standard.
Right?!
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

F o r u m Jump

Similar Threads Chosen at Random
Thread Thread Starter F o r u m Replies Last Post
Ground roof top antenna to neutral-ground of power line? sdowney717 Generators & Electric Motors General Discussion 43 12-12-2013 09:38:09 PM
Ground Hog Day! David M. Lyon Antique Gas Engine Discussion 26 02-03-2011 05:40:33 PM
6V positive ground vs. negative ground Scott Generators & Electric Motors General Discussion 36 09-29-2009 10:48:28 AM
Long Frame or Short Frame MCH02 Maytag Engine Collectibles 20 06-20-2009 07:57:55 PM
Short Frame - Long Frame blake in spokane Maytag Engine Collectibles 3 10-13-2008 12:00:39 AM


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 01:34:14 PM.

Smokstak and Enginads site search!


All use is subject to our TERMS OF SERVICE
SMOKSTAK® is a Registered Trade Mark - A Community of Antique Engine Enthusiasts
Copyright © 2000 - 2016 by Harry Matthews P.O. Box 5612 - Sarasota, FL 34277