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FAMCO 100 Vertical Mill, Pancake Motor, VFD, Cold Start Problems

el bob

Plastic
Joined
May 21, 2012
Location
North Bay
Picked up this machine a few years back. (thread link) It's always had an issue where the VFD will trip on over-current when cold-starting the spindle if A) it's cooler than say 60degF in the shop and B) the variable speed head is in high gear, or wound to a high speed in low gear. Once the spindle is warm, over-current does not trip on normal starting.

I bought a service manual with the machine back then, and the lubrication diagram is not a perfect match for my machine. Where the manual describes a grease zerk, this machine has a factory oil cup with adjacent factory placard specifying oil type. This is off to the right hand-side of the variable speed crank handle on the top of the head.

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There is also what I assumed was a grease zerk normally hidden under the sheet metal cover of the pancake motor, that is not mentioned in the service manual. Does that look like a grease zerk? I've read recently about fittings that look like grease zerks but are meant for pressurized oil fill.

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With cover installed.

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General view.

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Motor name plate.

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The head was noisy ("rackety") when I got it. I asked and was told by the two folks who were there when I bought the machine (job shop machinist, and an automotive machinist / large engine rebuilder) not to worry about it, that it was not an issue. When a mech engineer friend visited and saw the machine for the first time last year, he gave me the sideways look when he heard the thing run. He thought it did not sound good, that the bearings might be toast.

Pivoting -- VFD is set by the book, using motor name plate data. Hitachi WJ200-015SF VFD, and factory 1HP pancake motor. At 4.2Amp for B012 (motor current rating), when cold, it will frequently not start at all, even in low gear. For the first time since owning it, I needed to temporarily bump the programmed current rating to 5.0Amp to get it to start. No amount of hand rotating to "loosen up" cold grease and oil made it possible to avoid increasing the programmed output current rating. Once warm, b012 can be returned to motor name plate values.

Other VFD settings if helpful: VFD is set for 150% output overload protection (B022 12.0Amp), which equates to a 12.0Amp output trip (B022) to protect the WJ200-015SF, versus specifically the motor. Motor thermal current rating parameter B012 is set to match name plate of 4.2Amp. B049 is 0 (HD), B013 is 1 (constant torque). A082 AVR output voltage setting is 220VAC to match nameplate. Input line voltage is 240VAC, single phase.

Output over-current on acceleration code. E05.4 (spindle turn-on in this case).
View attachment 216205

DC Bus Voltage at trip time. 323.5
View attachment 216207

Output current at trip time. 10.09 (B012 = 4.2Amp)
View attachment 216208

Output frequency at trip time. 28.02
View attachment 216209

I now wind-down the variable speed selector prior to shutting off the mill, when I am done using it for the day. That step, combined with taking the first cold start in low gear, seems to help avoid failing to start-up with E05.4 trips on cold start. I am a little concerned it might be getting worse.

I am hoping some of you can share some insight.

1) Any chance the fitting on the back of the pancake motor is for oil not grease, and I'm making things worse by greasing it?

2) Oil cup on right side of head, marked "FILL DAILY ... USE SAE 50 OIL" only accepts about one drop out of the oil can. Any more and it overflows back out of the cup. Is that normal given that it is not being run for 8 hours in a day?

3) The machine does not have a designed-in neutral position for the spindle drive. I can lever the gear selector by hand and rotate the spindle relatively freely by hand, but the slightest slip on the selector level and it engages one of the gears, so I dare not mess with it under power. Anything tips for working through cold starts?

Thanks for taking a look. Questions above are tailored to checking basics. If the head needs a tear-down and rebuild, I am comfortable with digging into that. Would like to get some feedback first and see if that's what has to be done.
 
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El Bob,
A friend with a Toyota Landcruser restoration shop got a Famco 100. I happened by the shop and it was just sitting around, not connected to power. It needed 3 phase- they had single phase. After I badgered them about it, they somehow got their hands on a 2HP rotary phase converter. I hooked it up for them, and wired up the mill. When we tried to run it, it turned slowly, and after a few minutes the thermal relays shut it off due to overheat. At first I thought that the problem might be a reversed phase, but that did not help and it still turned slowly and overheated.

I had to depart for my home in California (they are in Colorado), and after downloading the service manual for the pancake motor, I have become somewhat convinced that the issue is VERY old grease which provides too much drag for the motor to overcome when cold and get up to speed (1725 RPM??). My guess is that that motor has very low torque at low speeds inherently. It probably develops the 1 HP only at operating speed (conjecture on my part...) If a motor is running at low speed with full voltage applied, there is insufficient back EMF to cut down on the voltage that the windings see (winding voltage = Lines Voltage- back EMF generated by the motor rotation). This causes a high current in the motor, with consequent overheating. If I were at their shop I would tear down the motor, clean and repack the bearings. I have suggested it many times to them, but they are too busy to get to it. They keep mumbling about an electrician, but I think it very well could be old grease. Who knows?? Perhaps it is the same for you.

I spoke with the kind folks at H&W about possibly replacing the motor, and they thought that a Bridgeport motor would do the trick very nicely. Cost was several hundred bucks on Ebay to more like $800 or so for a newly rebuilt one you could trust. That might be an avenue for you to pursue. The NMTB 30 spindle should be able to handle more than 1 HP, but I would chat with an expert like H&W before committing to it. That motor is a very peculiar beast- as the saying goes.."They don't make 'em like that anymore".

Sorry I have no answer, but if you have time and energy, try pulling the motor apart. The service manual had a blow by blow procedure, and they did make a lot of noise about servicing the bearings on a regular basis. If you DO pull it apart, I would really appreciate a note about how it went, so I can pass it along to my friends.

Best wishes,
Michael
 
Are you absolutely certain the windings are connected properly for 220 V rather than 440 V? I believe that same Fairbanks pancake motor was used on Bridgeports back in the day. I powered one of those recently with a WJ200, but the kind that takes 120-V input. It works just fine. While it is in California SF Bay Area, the shop is unheated and plenty chilly.
 
ferretlegger said:
El Bob, ...
ferretlegger, thank you very much. Tipped by your post, I found the service manual online (link here) for the motor and it has been enlightening. I think you're on to something. I will post-up what I find.

rklopp said:
Are you absolutely certain the windings are connected properly for 220 V rather than 440 V?
rklopp, I dug up the photos from when I re-did the motor connections to separate the drum switch and have it work as a signal-only FWD/REV input to the VFD. The photos do not capture perfectly all stamped motor wire labels, but those that are visible match the 220V pattern on the motor name plate, and do not match the 440V pattern. That terminal box cover would likely be the first piece removed for motor work to take place off-machine so I can check the groupings again. Side note - The machine ran what was a hair under a 1HP roughing cut earlier this month, driven through the variable speed pulley drive. Not very specific, but it has always seemed to have plenty of power once it is up and running.
 
rklopp said:
Are you absolutely certain the windings are connected properly for 220 V rather than 440 V?
Pulled the wiring out and verified for 100% certain, motor is wired correctly for 220V.

19.jpg

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Pulled the motor. I found that it spins freely. Holding the fixed stator frame, resting its side on the table, I can spin the rotor with three fingers pressing lightly. I can use my whole hand, spin it faster, and the rotor will remain spinning for more than a few rotations -- gradually reducing in speed.

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With the vari-speed drive belt no longer engaged, I grabbed the spindle and it is still stiff. This appeared to dictate that instead of the problem being in the motor, it appeared to be in the driven gear train and/or spindle.

14.jpg
 
FAMCO 100 service manual recommends greasing the feed gears and back gears, which requires removing the belt housing.

Lots of greasy debris in the belt housing. I am assuming it is quite literally grease plus belt dust. The drive belt that is in the machine looks, to my untrained eye (re belt wear), new.

15.jpg

A good thread on the non-metallic back gear in the FAMCO 100 head stock is this "Help with a non-metallic gear" thread here on PM from 2013. My machine appears to have a good reinforced phenolic gear, but the small metal back gear underneath it (not visible in photo below) appears to have a lot of wear, and resulting slop, in the gear teeth. This is where I think the rattling I frequently hear comes from. The spindle can be rotated independently of this lower gear, back and forth (grabbed at the spindle nose), slapping into opposing gear tooth faces of the small back gear.

16.jpg

I found what look like paint flakes in the area where the spindle pulley hub engages with the spindle spline sleeve (names from parts list for quill housing). The machine has no top cap over the draw bar, and it had a not-very-careful off-white paint job in a prior life. Shown below is the top surface of the spindle spline sleeve. This is exposed to view after the belt housing is removed.

17.jpg

Next is a view of the bottom of the removed belt housing. The belt housing casting captures and includes the spindle pulley hub upper bearing, the spindle pulley hub, and the spindle pulley hub lower bearing. Only the bottom of the spindle pulley hub is visible in the photo below.

With the belt cover housing sitting on its side, on the bench, the spindle pulley hub is stiff to rotate. With nothing connected to it, only the resistance of the two bearings, it is stiff to rotate. More torque (subjectively sensed by trying to turn it with my fingers) is required to rotate the spindle pulley hub in isolation, then is required to turn the motor rotor in isolation.

18.jpg

Next is an overview picture of the removed components.

11.jpg
 
Spindle pulley hub and bearings parts breakdown drawing.

22.jpg

Fairbanks Morse QZA* (on the mill), QZAE, QZAC, QZACU, drawing for frame sizes L4060-L60105, 4060-65117 (frame 4570 on the mill). Something of note is that the motor rotor does not appear to have rotor bearing lubrication holes or plugs, like are shown in the motor drawing from the Fairbanks Morse QZA service manual. The holes are exactly where the drawing says they will be for stator bearing lubrication, but there are no holes where the drawing says they would be for rotor bearing lubrication.

FRAME4060-65117Drawing.jpg

Picture of what looks like green grease pushing out past the stator bearing. This could be from injecting new grease into the stator bearing grease fitting without the opposing stator bearing lubrication plug being removed. Picture below was taken prior to removing motor from belt housing, but after beginning to lift it up.

13.jpg

Changing topic for next photo, motor pulley splines were dry. Picture below shows internal splines on motor pulley sliding half (name from parts list for belt housing assembly). Will clean and grease the splines before re-installing. (Not planning to re-install anything until a root cause for the high rotating resistance problem is identified, and fixed.)

12.jpg

Two of the four flat head screws that attach the reinforced phenolic 68 tooth back gear to the 68 tooth gear hub appear to have backed out a little. The two screws that have backed out a little are located opposite to each other. This photo shows one of them on the left, and shows a smidge of the other screw that appeared backed out on the far right.

23.jpg
 
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In picture 2 of post #8, what is the right way to remove the top small bearings on the right?

...

After taking apart the mill in the steps shown in pictures (from service manual), the following is what I have learned: Of the three rotating assemblies that the motor has to spin-up, the spindle is the stiffest to rotate.

Easiest to rotate, to hardest to rotate:
  • Motor rotor [post #7, picture 1, tested off-machine, motor assembly on bench]
  • Spindle pulley hub [post #8, picture 4, test off-machine, belt housing with mounted spindle pulley hub assembly on bench]
  • Spindle [post #8, picture 2, tested on-machine, disassembled as shown in picture, grabbing snout of 1/2" end mill holder to rotate the spindle]

I tried comparing rotational resistance both with and without a toolholder clamped into the spindle taper. It did not seem to make a difference. The spindle pulley hub (separates from the spindle, stays with belt housing) seems stiffer and harder to rotate than I would expect for two ball bearings on a shaft, but compared to the spindle it's much easier to rotate. Three finger tips and the the spindle pulley hub rotates, and continues to rotate a little after letting go. The spindle requires a tight grip like gripping a hammer handle, and only rotates as much as it is turned.

Is this what you would expect?

Any advice, tips, suggestions and such are appreciated. If any of what I have posted is impertinent, or otherwise not-good-practice for presenting findings, please let me know. I appreciate you taking a look.
 
El Bob,
Wow, you do not do things by a half do you? I am very happy you are doing this and documenting it so well. If the motor bearing had just needed cleaning it would have been too easy. Sigh...

I do think you are finding out the answer. I still think that too much friction creates heat during the spinup to full rpm. Perhaps the spindle bearings need cleaning and regreasing. Does the quill move easily? is there anything that could put pressure on the spindle and distort it a little bit, causing the bearings to bind up? This thing seems quite a bit simpler than a Bridgeport head. My guess is that the spindle removes in a cartridge, but who knows. If it does, it may be reasonable to regrease the bearings. One possibility is that there is too much preload on the spindle bearings. That causes otherwise free running bearings to get tight. That preload may be made by tightening up some sort of collar.

You might drop the guys at H&W a note or call them and see if they can take a look at your pictures. They are really helpful, and know mills very well. They might have some good tips.

Please keep up the dissection. The cops want to find out the cause of death!!

Best wishes!
Michael
 
Two metal back gears, 76 tooth and 26 tooth. Looks like the 76 tooth gear is bronze (assumption) and is wearing away, both onto the 26 tooth gear, and into gold colored dust on the sides of the housing.

IMG_5012.jpgIMG_5016.jpgIMG_5019.jpgIMG_5024.jpgIMG_5025.jpg
 
Feed gear shaft and feed gear idler shaft top bearings are are FAFNIR 202PP. Back gear jack shaft top bearing is FAFNIR 204PP. Did some searching and it looks like the replacement new part numbers would be 202PPG and 204PPG. Back gear jack shaft bearing shown below.

IMG_5086.jpg

Feed gear shaft appears to receive the oil from the oil cup shown in post #1 photo 1. It appears to drip down through a tube running within the belt housing, down into a snug fit part that rides in the top of the feed gear shaft.

IMG_5077.jpg

The two, of four, slotted flat head screws attaching the non-metallic back gear to its hub that backed out, were only stopped form backing out further due to running into the outer race of the 204PP ball bearing. It would seem that, whenever that gear was turning, those two screws would have been rubbing against the outer race.

IMG_5031.jpg

Overview picture of feed gear area.

IMG_5041.jpg

Condition of top feed shaft gear.

IMG_5056.jpg
 
I hesitate to post these. Maybe it will help someone in my shoes in the future avoid making a similar mistake. I screwed up (see pictures in the next post). This did not go as well as I had hoped. I cut into the shafts. The shaft will have to be repaired. Please tell me if I'm mistaken. The back gear jack shaft and the idler gear shaft are short, and attach to fewer pieces. The feed gear shaft is longer and is more integrated.

I would not try and remove them the same way again. I don't have an oxy fuel setup to try and quickly heat the bearings and remove them off the shaft, nor was I excited about working with the doors open when it was below freezing outside, and worrying about running a hot flame next to all that grease. This was all short sighted as running the grinder with a cutoff wheel ended up necessitating running with the doors open and a fan running anyway. When I checked at the end, the temperature and humidity monitor said it was 34 degrees (F) inside the shop.

IMG_5127.jpgIMG_5140.jpgIMG_5146.jpgIMG_5167.jpgIMG_5176.jpg
 
Follow-up to last post. Pictures of damage from bearing removal with grinder and cutoff wheel. Separately, it also shows the grease spray behind the back gear jack shaft, and shows the gear bear hub that supports the non-metallic 68 tooth back gear.

IMG_5221.jpgIMG_5227.jpgIMG_5228.jpgIMG_5229.jpgIMG_5234.jpg
 
El Bob,
What a bummer! Aieeee! Of course I never did anything like that...Oh no. I never did anything like that.:sulk:

Well, I guess you are committed to taking those shafts out now. If cleaned up a new bearing MIGHT still run on them, but you might not sleep well knowing about it. My guess is that the shaft can be repaired. "Abom 79" and "Keith Fenner" on YouTube have both shown repairs on shafts like that using TIG welding to build up the cut parts and then turning down to fit the bearing. Finding replacement shafts is probably unlikely. Machining new ones from 4140 would probably be a reasonable thing to consider, if the shafts are not too long or too featured.

Anyway, don't despair. Shit happens in machine shops. To everyone! This IS a situation you can get past. Take a deep breath and relax. Have a beer or whatever tonight to celebrate the New Year, and add something else to the "To DO" list. As I have become fond of saying in recent years, "This too will pass".

All the best, and thanks for posting all this. Even the bad stuff. I am learning a lot.

Michael
 
I don't think that is a Bronze. There is a family of "high strength" Brasses often used for gears that is more likely.

Good to know, thanks.

What a bummer! Aieeee! Of course I never did anything like that...Oh no. I never did anything like that.:sulk:

Thanks, the sentiment helped. :)

Well, I guess you are committed to taking those shafts out now.

Shafts are now out. Pictures will be in following posts.

...

Feed gears removed.

Where things left off after removing the top bearings.

IMG_5242.jpg

48 tooth feed gear, from top of feed gear shaft.
IMG_5251.jpg

Remaining feed gears.
IMG_5253.jpg

Remaining feed gears slid off together.
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Exposed feed gear shaft, with retaining ring still in place. Shows sliding shaft key, actuated indirectly by feed selector handle on front of head.
IMG_5278.jpg

What I wanted to do was make it easy to clean out the area around the feed and back gears in the quill housing casting (name from parts list). It seemed to have a mix of a few machining chips, yellow/gold colored gear wear dust (assumption), some dirt/dust (assumption) and thrown, collected grease. Some of this is shown in the pictures in posts #12 and #13.

Knowing what I know, I think the different gear shafts and assemblies could have been removed intact, without removing the three top bearings shown in post #14.

If I were to do it again, this is what I think I would try:

...

Once the motor and belt housing have been removed,

[Feed Gear Shaft]
1) Remove the power feed cross shaft assembly. (It pulls out all together.)
2) Remove the feed selector shaft assembly. (It pulls out all together.)
3) Remove the feed gear shaft assembly. With the above two shaft assemblies removed, the feed gear shaft assembly can now pull out the top.​

[Feed Gear Idler Shaft]
4) Remove the feed gear idler shaft. With the feed gear shaft assembly removed, the feed gear idler shaft gears now have a clear passage to pull out the top.​

[Back Gear Jack Shaft]
5) Partially remove, by lifting and cribbing-in-place, the back gear rack tube assembly. The back gear selector shaft assembly and rack and pinion mechanism can be used to incrementally lift the back gear rack tube assembly up.
6) With the back gear rack tube assembly lifted up, lift the back gear jack shaft assembly up. Alternately lift both assemblies up until clear, and pull both out the top.​

...

I post the above in case it is helpful to anyone in the future with the same machine. A quick side note is that this machine does not perfectly match the parts breakdown diagram. The manual recommends using a universal joint to access hard-to-reach fasteners that secure the belt housing to the quill housing, and the parts breakdown diagram shows these fasteners located on the inside of the quill housing. The two castings are different on this machine, the fasteners are located outside the castings and are easy to access. The oil cup up on the belt housing (right side) is also not included in the service manual, but is a part of this machine, feeding oil through a line in the belt housing down and into the top of the feed gear shaft.
 
Feed gear idler shaft removed. Exposes view of back gear rack tube.

With feed gear idler shaft removed, can now see sliding movement of back gear rack tube.

Debris from cutting out the upper ball bearings are visible in these photos. The half-a-ball and the small pieces of bearing race were removed after the photos. This area needed cleaning before-hand, and now needs it more.

Seat of feed gear idler shaft lower bearing.
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Back gear selector set to low range.
IMG_5308.jpg

Back gear rack tube is in its lowered position. Back gear selector shaft has a pinion gear on it, which raises and lowers the back gear rack tube. The key in this photo rides up and down the same slot in the quill bore as two other keys. One on the quill, and one of the depth stop assembly.
IMG_5310.jpg

Back gear selector set to high range.
IMG_5311.jpg

Back gear rack tube in its raised position.
IMG_5312.jpg
 








 
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