53 ee with speed problem

gary tisdel · May 10, 2008

hi guys,

after finding this site and spending quite a bit of time learning on this forum about ee`s, i was fortunate enough to find a 53 ee not too far from me and was able pick it up.

the previous owner has owned a number of ee`s and was able to help me with quite a bit of info and some manuals.

the first issue i need to work out is it will only spin up to 750 rpm. , the speed control appears to be working backwards as the dial says to turn clockwise for higher rpms and you have to turn ccw for higher rpm`s.

i opened the controller box and noticed a little oil in there and there are three round things in the upper right corner that seem to be growing green.

gary

macona · May 10, 2008

Is this a motor generator drive?

I have/had the same DC control box as you. I had to replace the three black resistors in the corner there. The insulation deteriorated and they came apart. You may have to do the same.

But first thing you need to do is get a manual from monarch so you have the correct schematics for the machine you have. Then go through and make sure the wiring is right.

peterh5322 · May 10, 2008

A '53 could be mid-WiaD or late M-G. '53 was just about the last year an M-G was offered.

The tailstock end of the machine had its cover removed. That was the place to check for tubes (WiaD) or the exciter (M-G).

The DC Panel is of the "three resistor" type.

There are also "one resistor" and "two resistor" DC Panels.

rke[pler · May 10, 2008

The absence of ventilation panels on the end cover makes me think that this is a motor/generator unit. If so then diagnosing a problem in a motor/generator speed control is pretty simple - it's pretty much all in a large rheostat controlled by the speed control knob. Follow the shaft on the speed control knob back under the headstock, it should have a sprocket with a chain driving a rheostat - take some pictures of the rheostat and wiring and post them. Something is messed up in there - if the speed regulation happens only at the top half of the knob movement someone may have swapped the armature and field wiring there.

gary tisdel · May 10, 2008

hi guys,

sorry, its an mg setup, i forgot to put that in my question.

macona; i think i do have the manual, the previous owner gave me a manual that has schematics. where did you purchase those resistors at ??

peter; you are correct about it having three resistors, anyone know what they do ?? should i just replace all three or diagnose them and replace as needed.

rke[pler; the control knob works in reverse to the direction arrow on the plate. i`ll take a pic tomorrow.

thanks,
gary

rke[pler · May 10, 2008

gary tisdel said:
rke[pler; the control knob works in reverse to the direction arrow on the plate. i`ll take a pic tomorrow.

I believe you, and there's one or two ways to make it do that. One would be to put a twist in the chain from between the sprockets on the speed control knob shaft and the rheostats, the other would be to mess with the rheostats - thus the request for pictures under the headstock. The rheostats should look something like those in this recent eBay auction: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270231376092

The reason I mention this is because messing with the rheostats can also cause the speed problem that you're having.

gary tisdel · May 10, 2008

hi rke[pler,

i`m not near the machine today to take a pic but will tomorrow.

thanks for the help, it is appreciated.

gary

donie · May 10, 2008

Years ago an old guy advised me to try to start the machine at around 1000 rpm rather than at full speeds often. He said those three resistors act as a buffer, so the machine doesnt slam when starting at high speeds. He said starting the machine many times at high speed can cook those resistors.
I dont know if thats all true, but I have got in the habit of turning down the speed knob for restart when working at higher speeds. After years of use, those resistors are clean and white.

The real Leigh · May 11, 2008

I think it's always desirable to start the machine at low speed and bring it up. It gives you a chance to catch the chuck key.

This doesn't apply to work-in-progress, although it's probably still a good idea.

- Leigh

macona · May 11, 2008

I got them from surplus sales of nebraska. This is what I bought:

(RWF) RW35-3100 Resistor, 3100 Ohm, 38w 1 $ 9.00 $ 9.00
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
(RWF) RW35-2000 Resistor, 2000 Ohm, 55w 1 $ 7.00 $ 7.00
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
(RWF) RH50-6.3K Resistor, 6300 Ohm, 50w 2 $ 4.75 $ 9.50

I think two were in parallel (6300's) and one was in series 3100k? Dont remember now, its almost been a year. Search for my old posts and there might be something.

The real Leigh · May 11, 2008

macona said:
I think two were in parallel (6300's) and one was in series 3100k? Dont remember now, its almost been a year. Search for my old posts and there might be something.

www.surplussales.com Yes, Bob Grinnell has just about everything, and thinks very highly of each piece ;-)

Make sure the power rating is correct. Higher power resistors are larger and may not fit in the available space.

Here's the Ohmite webpage for their current products http://www.ohmite.com/cgi-bin/showpage.cgi?product=270_series

- Leigh

gary tisdel · May 11, 2008

hi guys,

here`s some pics of the rheostat. the rheostat has a little oil on it from a leak coming from above, not a lot of oil , but not completely dry.

the chain and sprockets look as if they are working properly and it does move the center piece in the rheostat.

macona; the resistors don`t appear to have any in tandem, is the reason you went with two because your box had two in tandem ??

thanks ,
gary

donie · May 11, 2008

My older ee seems to sweat oil from somewhere and drip right on the reostat from the headstock bolt. I cleaned the reostat with electrical cleaner and fashioned a piece of plastic to act as a roof to keep oil off it.

macona · May 11, 2008

One of the resistors I was not able to find so I did a little rewiring. I would have to see the schematic again to remember what I did.

gary tisdel · May 13, 2008

hi guys,

i dug through the paperwork that came with the machine and it appears i have electrical schematics for a wiad, not the one i need. (mg with three resistor dc panel).

i pulled the three resistors out today and the ohms macona listed for his machine don`t match up.

my machine has;

(2) c-h 11003h29a 1600 ohm

and (1) c-h 1103h29a 2000 ohm

i looked in the links that leigh provided ,and did a search on the surplus sales site and on the ohmite page and was compeltely baffled at what i`m looking at. i`m going to call surplus sales and see if someone can guide me to what i need.

gary

i forgot to ask: what is the best way to clean the oil film of all the electricals in the dc box ??

rke[pler · May 13, 2008

Those are the correct resistances. The 1600 ohm guys are in series and the 2K by itself. I'd clean the contacts and put them back in place.

If you have an electronics shop nearby they'll have an appropriate spray cleaner. It may end up being the same stuff as brake cleaner, I don't really know. It's not like you can ask for tuner cleaner anymore...

gary tisdel · May 13, 2008

hi rke[pler,

are you saying i shouldn`t replace them?? i`m thinking the green stuff growing out of them would be bad.

i`ll test them tonight .

thanks,
gary

The real Leigh · May 13, 2008

gary tisdel said:
are you saying i shouldn`t replace them?? i`m thinking the green stuff growing out of them would be bad.

Hi Gary,

The green stuff would be a copper salt, probably copper sulfate. It just indicates that the machine was exposed to a contaminated atmosphere at some point.

As long as the values are correct, I would leave them alone. Judicious application of a wire brush should remove the nasties.

I normally use WD-40 for cleaning electrical contacts. Works fine. There are many other contact cleaners on the market, some quite expensive (De-Oxit for example), but most work no better than WD-40 (based on about 50 years of repairing electronic stuff).

- Leigh

rke[pler · May 13, 2008

If they're measuring the right resistances they're fine, just clean up the contacts with a small wire brush and reassemble. The green stuff on the contacts is just patina crud from the brass. I'm not really sure why you're looking at the resistors, they are part of the antiplugging and field acceleration relay setup and you have something else going on so far as I can tell - something is whacked in the main rheostat, probably in the wiring to it from the bottom of the DC box.

If you can, try measuring the resistances at the rheostat. You may need to disconnect the wiring as the DC panel might be adding or removing some of the resistance. Basically, one side should steadily change in resistance while the other remains unchanging until halfway through, then the function should swap. The one changing resistance at the bottom half of the range is the armature pot, the other is the field. Note which one is changing when and the maximum resistance (other than infinite) that you see, and we'll try to compare to someone else's rheostat. You'll also want to follow the wires into the DC panel. I'm not 100% sure but the affected wires should be GR1, E2, GF2 for the generator (armature) and E1-2, F2 for the other (field).

gary tisdel · May 14, 2008

hi guys,

i was looking at the resistors because of the green growing on them, not because i knew what to check, just looking for things that looked out of place.

the 2000 ohm resistor measured 2.110
neither of the 1600 ohm resistors would give me a reading, the ohm meter would never stop moving.

i checked them by themselves with nothing hooked to them.

because rke[pler says its not possible to be my speed problem, i cleaned everything and reinstalled them.

pulled the wires from the rheostat and traced all wires back in the dc box.

with the sprocket facing you they were wired in the order.

front (behind sprocket l-r) gr1,gf2,e2
rear (closest to control knob) e1,f2

the resistances;

front; gr1-gf2= .628-.320, then changing to 344.0- 0
gf2-e2= .3-4.0, then changing to .4-.65

rear; e1-f2 = .1-334 no change , constant upward resistance.

don`t know if the wires were in the correct order on the rheostat as i don`t yet have the proper schematic.

gary

edit; found this thread that shows rheostat wired correctly
http://www.practicalmachinist.com/vb/showthread.php?t=100596&highlight=mg+wiring+diagram

53 ee with speed problem

Aluminum

Attachments

Diamond

Diamond

Diamond

Aluminum

Diamond

Aluminum

Diamond

Diamond

Diamond

Diamond

Aluminum

Attachments

Diamond

Diamond

Aluminum

Diamond

Aluminum

Diamond

Diamond

Aluminum

Similar threads