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?
need a generator guru
- Thread starter mhooker32
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ihateminimumwage
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From the info you provided it sounds like you have it figured. If you have one dead pole, it's only going to pick up the other two opposing sides. Your math does seem to add up to that.
TractorJeff
Well-known member
Older Millers came 2 ways. (1980's)
1st was 1800 rpm generator only. Flip switch to weld mode and have no generator.
2nd was Welder/Generator combo so the Weldor could be doing his job while the Fitter was Grinding the next weld area.
Then the Dealer would be selling a Unit to a customer which was Welder OR Generator only and the Customer would say he wanted the 2nd option. The Dealer would do a "conversion" without changing the nameplates or the outlet configurations.
You then end up with what you are describing
1st was 1800 rpm generator only. Flip switch to weld mode and have no generator.
2nd was Welder/Generator combo so the Weldor could be doing his job while the Fitter was Grinding the next weld area.
Then the Dealer would be selling a Unit to a customer which was Welder OR Generator only and the Customer would say he wanted the 2nd option. The Dealer would do a "conversion" without changing the nameplates or the outlet configurations.
You then end up with what you are describing
im going to go over it one more time today, but i fear its the rotor. rotten luck if it is
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?
thanks
thanks
