Coast Resorts Open Roads Forum: Tech Issues: generator/welder issue.
Open Roads Forum Already a member? Login here.   If not, Register Today!  |  Help

Newest  |  Active  |  Popular  |  RVing FAQ Forum Rules  |  Forum Posting Help and Support  |  Contact  

Search:   Advanced Search

Search only in Tech Issues

Open Roads Forum  >  Tech Issues

 > generator/welder issue.

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 2  
Next
mhooker32

ny

New Member

Joined: 12/03/2022

View Profile


Offline
Posted: 12/03/22 06:16pm Link  |  Quote  |  Print  |  Notify Moderator

miller generator/welder. at 1800 rpm, the generator portion should output 60 hz, 120v. . its 4 pole. output is 65v at 40 hz.. will output 60hz and 120v at about 3400 rpm. . the welder portion is a separate stator, it also outputs half the voltage and HZ. i suspected a bad pole on the rotor,. as a half assed test, i applied 12v to the slip rings. inserting a thin welding rod at each pole showed the same magnentic attraction. i was expecting a dead pole. . ohms out at 18 ohms, which is correct. on the 240 volt plug, i get read 60 v, 40hz from one leg to neutral or ground, . 120v and 40hz from hot to hot. . . runs like a 2 pole unit. im really stuck . . i ran it at 3400, and i get 60hz, but thats way to high rpm. for a moment, i saw the fluke spike to 130hz, but when i set it to min max it didnt do it again. . i can send a schematic. the fact that it has a generator stator and a welder stator that has the same issue makes me think its somehow the rotor. if it is, its a goner. i hope not. it spent a lot of time getting it to run like a top, now this. any thoughts?

enblethen

Moses Lake, WA

Senior Member

Joined: 01/05/2005

View Profile






Posted: 12/03/22 06:32pm Link  |  Quote  |  Print  |  Notify Moderator

Model and year of Miller unit?
Could be RPM problem. Some are 3600.


Bud
USAF Retired
Pace Arrow

2003 Chev Ice Road Tracker


MEXICOWANDERER

las peñas, michoacan, mexico

Senior Member

Joined: 06/01/2007

View Profile


Offline
Posted: 12/03/22 11:08pm Link  |  Quote  |  Print  |  Notify Moderator

A separate stator requires a revolving field. If the D.C. isn't pure (read failed exciter rectifier) then RPM count and stator voltage would be affected. This really should be diagnosed with a handheld oscilloscope.

mhooker32

ny

New Member

Joined: 12/03/2022

View Profile


Offline
Posted: 12/04/22 07:28am Link  |  Quote  |  Print  |  Notify Moderator

rectifier tests good. i also disconnected the bridge and ran pure 12v straight from the battery to the brush holder. still low HZ. at the same rpm, the output voltage would be reduced with only 12v, but the HZ should still be 60

mhooker32

ny

New Member

Joined: 12/03/2022

View Profile


Offline
Posted: 12/04/22 08:52am Link  |  Quote  |  Print  |  Notify Moderator

ok. just looked at it. inserted thru the back a long 1/4 inch steel rod into the opening between a pole and the stator. with 12v on the brushes, you cant even pull out the rod. disconnect the 12v and the rod releases. it does the exact same thing on all 4 poles, equally. i think that rules out the rotor. i ran the machine at 2200 rpm with 12v on the brushes. 39-40 hz, about 30v ac . with the power to the slip rings disconnected, i still get 39-40 hz just from the residual magnetism, but of course very low AC, 1.5 volts. put back to normal with a new bridge rectifier brings me back to the orig problem, 39-40 hz, 70 volts AC at 2200 rpm. should be over 60hz and 120v. what else could it be? the stator is two windings with a center tap. both X and w outputs on the stator exhibit the same condition. you see the same acrosss X and Y. which are the hot legs for 220 v. there i ger the same 40 Hz, and around 120v. WTF could it be?

enblethen

Moses Lake, WA

Senior Member

Joined: 01/05/2005

View Profile






Posted: 12/04/22 08:53am Link  |  Quote  |  Print  |  Notify Moderator

May want to read through this:
Miller troubleshooting

MEXICOWANDERER

las peñas, michoacan, mexico

Senior Member

Joined: 06/01/2007

View Profile


Offline
Posted: 12/04/22 05:15pm Link  |  Quote  |  Print  |  Notify Moderator

One of 3 phases open on the secondary stator winding will also affect Hz

theoldwizard1

SE MI

Senior Member

Joined: 09/07/2010

View Profile


Offline
Posted: 12/05/22 03:31pm Link  |  Quote  |  Print  |  Notify Moderator

Any split phase generator should have the same resistance from the output leg to neutral. If not, you have a bad stator. If there are only 2 brushes, then there is only one rotor field.

Remove and inspect brushes. Clean slip ring.

Unless it is an inverter generator, the frequency is controlled by engine RPM. It is NOT a coincidence that 60 Hz generators run at either 1800 or 3600 RPM (multiples of 60).

theoldwizard1

SE MI

Senior Member

Joined: 09/07/2010

View Profile


Offline
Posted: 12/05/22 03:32pm Link  |  Quote  |  Print  |  Notify Moderator

MEXICOWANDERER wrote:

One of 3 phases open on the secondary stator winding will also affect Hz

Who said anything about 3 phase ?

MEXICOWANDERER

las peñas, michoacan, mexico

Senior Member

Joined: 06/01/2007

View Profile


Offline
Posted: 12/05/22 11:52pm Link  |  Quote  |  Print  |  Notify Moderator

Me...

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 2  
Next

Open Roads Forum  >  Tech Issues

 > generator/welder issue.
Search:   Advanced Search

Search only in Tech Issues


New posts No new posts
Closed, new posts Closed, no new posts
Moved, new posts Moved, no new posts

Adjust text size:




© 2023 CWI, Inc. © 2023 Good Sam Enterprises, LLC. All Rights Reserved.