Trouble with 1955 Monarch 10EE - Runs but no Power.

[Newman109]

Hello,
I've been around for a while but have not previously posted on a Monarch 10EE. I'm posting for a machinist friend who is not a member here. He is winding his shop down after more than 35 years. He does both manual and CNC as well as welding. The machine in question is a 1955 Monarch 10EE that he's had for quite a long time and which has had minimal use down through the years. Heretofore the only trouble that he's had with it was the cutting oil pump which leaked and which was repaired with the addition of a seal. He wishes to make sure that it works properly for the new owner as this and many other machines will eventually go to auction.

The problem is that it has lost power. In low range, he will attempt a cut and the cutting tool will actually stop the chuck from moving. It can also be stopped by hand. In high range making a cut at say 600 rpm will cause the speed to drop to 400 or less rpm.

He, like myself, has almost no knowledge of the intricacies of the motor-generator unit or it's several iterations. Thus the reason for the request for help from the experts.

There are photos one of which of the controller area shows what I might think is a missing heater on the left. In operation, there appears to be a great deal of sparking at what appears to be the DC generator. This problem has just started very recently.

He is also interested in sources for what appears to be four carbon brushes. Any ideas will be much appreciated.

Thanks in advance.

 

[Newman109]

Well, as to the brushes, it's certain that they need replacement and adjustment. Anything to do with the variable resistor circuitry would leave both of us cold since we have no experience in that area.

Thanks for the response.

 

[Cal Haines]

The belt-driven unit on the top is the exciter, the one on the bottom is the generator. Which one is sparking?

Please post a closeup of the commutator.

Monarch has brushes at a reasonable price. I recommend ordering a full set of brushes: DC motor, generator and exciter. Replacing the brushes on the unit that's sparking will probably fix your problem.

This is called the DC Control Panel:

The big relays at the bottom are the forward (F) and reverse (R) relays. There's no heaters involved, but the arc-chutes on the F relay have been rotated out of position and some sort of odd repair has been done to the middle contact. Please post a closeup of the F relay.

It appears that someone has replaced the spring for the relay at the top, in the middle (the AP relay). Also, the three resistors in the upper-right corner of the panel tend to fail and should be replaced. See this post: https://www.practicalmachinist.com/...-problem-with-m-g-machine.265676/post-2034250

Cal

 

[Newman109]

Hello,
The generator is the one that is sparking. I will recommend to my friend that he contact Monarch and order a complete set for the lathe.
I'll try to get a photo of the "F" relay per your request. If there were repairs made, it had to have been done prior to his having purchased the lathe some many years ago because I know that my friend never did any of that.

Thank you for the excellent response!

 

[Cal Haines]

If the generator isn't able to put out full voltage, that can cause your problem. Dealing with the generator brushes should take care of that. I need to see a photo of the generator's commutator to see if it also needs to be reconditioned.

If you remove the little cotter-pin from the spring assembly above the middle finger, you can lift the finger out and turn it over so that we can see what's going on with the contact. All five control fingers (with attached leads) are interchangeable, so I would probably swap it with the one immediately to the right, which carries a lot less current. (You need to swap the positions of the leads as well.) The arc-chute assemble above the relay rotates about the rod with the larger nut. It needs to be rotated into the same position as the one on the R relay.

Cal

 

[Newman109]

Follow up in re Monarch 10EE. My friend contacted the Monarch company and they were very helpful They understood completely what his problem was and sent him the correct brushes. After some commutator cleanup and brush installation, his 10EE is running nicely again.

He couldn't say enough about how nicely they treated him and the prices were very reasonable

Thanks for the suggestions.