Electrical woes on 2HL
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    Default Electrical woes on 2HL

    So I have repairs and repaint pretty much completed on my 2HL, and made my first cuts with the universal head...and all was well at around 4-500 RPM, then tried some light cuts around 1000...and popped the overloads a couple of times! So started trying to diagnose. I am NOT a whiz with motor wiring, but have some limited knowledge. Here's the background...had to buy a motor controller (used, but serviceable)and heaters sized for the 3HP Westinghouse motor. My first thought was maybe motor was wired for 440...I'm running 240. Clamp on ammeter on leads showed 10amps( I think I only checked two leads)...motor nameplate showing 8 amp (I assume plate is showing the FLA??) So pulled motor out, but before disconnecting, tested voltage on all three motor leads, and did another amp check, with no load. And this is where I start getting lost! With no load, my readings (T1, T2 T3) was 5-3/4, 1/4!!! and 5-3/4. Actually, my first check I didn't see the needle move on T2 as I was still on a 15A range...so I thought I had motor issue! I pulled connections (it WAS wired correctly for low voltage)
    I then ohm checked leads (after some research on how) and could NOT find a problem. So hooked it all back up and started double checking things starting with RPC...I am running a pony start 15hp, but UNBALANCED. I realize this can be an issue if the RPC sizing is marginal, but did not think this would be a reason for the low reading on one lead??? I don't understand why one leg is SO much different than the others on current draw! Can anyone explain?

    Here are some numbers...
    RPC line voltages (individual, one lead of multimeter grounded), L1 118v, L2 172v, L3 120v

    Voltages measured lead to lead...L1,L2=205v
    L2,L3=213v, L1,L3=237v

    (L2 is the generated leg)

    Ohms on motor leads, 1-4,2-5, and 3-6 all around 1.4.On7-8,8-9,7-9 around 2.4. No shorts to ground.

    After hooking it all back up, did a couple more amp checks. First with no load. And I swapped T2,T3 motor leads and tried it (direction reversed of course, but belts off) and the low amp reading was still on the center terminal of controller. Then wired and set it all up and ran under loads...(just powering head, no cuts) At 412RPM, got 6, 2.5, and 8amps. T2 still LOW. At 1085RPM, got 10, 5 and 12.5!

    I pulled one side of universal head apart for some mounting/casting repairs (have another thread going on that one) and found a black grease...seemed a little thick, and I am planning on a total clean out and re-lube soon, maybe Corn head grease? (Have read several threads saying oil as originally called for leaks out badly)

    Do you guys think this grease in the Universal head could be the reason for the high current draws at higher RPM's? Or do I have other issues? Is the low, low draw on one lead due to the RPC imbalance and if so, is it necessary to add some capacitors to try and balance better?

    I would sure appreciate some advice and opinions!

    Charles

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    Its good to hear everything is coming along. I have a 3hp 2HL motor I have no use for. If you can figure out what you need......The parts are yours for the ride.

    Andy

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    Andy, thank you for that! You have been great! Yes, the 2HL is pretty much complete except this issue. And of course finding a permanent location in the shop for it! That may be more an issue than the mechanical stuff! LOL I believe my motor is ok at this point, but not sure. I will definitely be in touch if I find out otherwise!
    Charles

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    When you tested the current, did you connect directly the motor to your RPC ( with that I mean not through the contactors of the mill, an external switch is fine)?
    Have you tested the resistance across the contacts of the magnetic contactors?

    Paolo

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    Do a megger test on motor leads to ground. Ohmmeters don't generate enough voltage in circuit to check insulation breakdown.

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    Paolo,

    I checked voltage at my RPC fused disconnect. Set up as L1, L2 (generated) and L3. First checked the 2 house legs without RPC running, then powered it up and checked all three both individually by grounding one probe of multimeter, touching other to each leg. Then checked across them. I checked Voltage also at bottom of motor controller with controller energized. (have a 110V coil powered separately) I have not checked resistance across contacts, but will today. I checked wiring from controller to motor also...all ok. (no open or shorts)
    Current checks have been at bottom of controller where motor leads hook up, below heaters, believe labeled T1,2 and 3. I did one check with clamp on ammeter at the peckerhead at motor when I had it partially pulled out.

    So now maybe more bad news. I just pulled universal head and drive off, and checked again no load and with spindle turning, to see if the grease in the head was causing some of the issues...nope.
    (all below is T1-3, with middle or T2 being the generated leg, fractions are approx)


    No load 2-1/2, 1, 2-1/4
    Spindle engaged...
    153rpm 6-1/2, 1-1/2, 5-1/2
    1088rpm 6-1/2, 2-3/4, 8-1/2
    1400rpm 7, 2-7/8, 9
    I then let it run at 1400, and after about 5 min it tripped overload again. Is the motor bad or???

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    I have seen the megger test mentioned in my research, but do not have that tester or any experience with one...I will look into maybe acquiring one and trying that. I was kinda hoping some one could look at my diagnosis/findings and steer me into most likely suspect...motor or the unbalanced RPC. From the research I have done so far, I thought my 15hp RPC running a 3hp motor, no vfd's, would not be a problem with balance. The RPC has run my Powermatic bandsaw over a year no problems, and has run my new to me 5hp 2H for a few times without problems.

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    I have a 2hl war baby with Westinghouse 3hp three phase motor that was originally running on 440 when the Navy had it.. I changed the overloads in the Square D starter sized to fla of the motor plate and changed the original 440 starter coil and never had a problem...When I got the machine I was running a home brew rotary phase unit with a Baldor 3500 rpm ball bearing motor and it was using run caps across the line..Since then, I have gotten 120/240/208 from the power company..I never had any problems but then I don't run the machine at top speed for any length of time..I have the old style motor with oil rings on the shaft bearings.. I had to make one new bushing for the drive end of the motor as it was badly worn probably from someone running the belts with too much tension...

    On the vertical head, it depends upon which type you are using as to whether the spindle bearings require oil or grease.. I think the light hi speed and std hi speed heads require spindle oil in the spindle bearings but others take #1 grease..

    If you have properly sized your overloads to the fla on the motor plate at low volt and they trip, you either have an overloaded situation or your motor is faulty provided that you have sufficient voltage present....I guess it could be possible to have a weak overload maybe.. Who knows? They are supposed to be sized closely to the full load amps of the motor plate on the voltage you are using unless the starter happens to be in an area where there is either warmer or colder air but that is a different situation I am sure...

    One thing that might be considered is how snug the bearings in the machine spindle are set...Sounds like something is causing an overload causing the overloads to trip..Ramsay 1

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    Not that surprised that you see low amps on one leg of the machine motor draw with an unbalanced converter. Still should not make the machine motor stop running after a few minutes. The motor should run fine on single phase after it is started, especially with no load on it. This almost sounds like you may have an issue with the motor starter relay or the heaters in the relay. Possibly one of them is defective and tripping out the relay. I would start looking there. To make the converter perform better I would add some capacitance across the line as Ramsay suggests. Maybe in the 10-15 micro farad /HP range. This will help the balance issue with low loads on the converter.

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    Hey Ramsey! It is a Standard High Speed Universal head. I've read several threads on lubrication for it, and I think it is supposed to have oil, but as mentioned in other threads, they then leak badly!! So I was thinking of maybe the corn head grease...but the vo-tech school and I'm sure lot's of others have run a light grease in them without problems...I am really just looking at possible causes for the motor current draw. The nameplate says 8 amps, but it is not marked FLA anywhere...probably not the convention when it was built. But I used that to size the heaters...I did size a bit on the low side as I wanted to make sure I protected the motor...maybe I'm just a tad low? At the higher speeds, it is drawing about 10amps on 2 of the leads, and that's not really under a cutting load. I am still learning motors, so tell me if I am wrong, but 10amps is still too high regardless of heater? And won't it draw more amps during a heavy cut?
    I placed transmission in "neutral" and turned the spindle by hand...didn't feel anything unusual and I think it's probably a reasonable "drag" I was feeling there. I have also turned the clutch/pully with clutch engaged by hand and it feels ok.
    So what is happening with the motor? Why such a drastic current difference on one leg? Is that normal?
    The motor starts nicely, and sounds good. I ran it at 1088rpm (no load...spindle turning only)for over an hour, and it was fine. At 1400, it trips out after a few minutes. These results match up with the current draw I'm seeing.
    I would certainly like to know where to go from here...
    Any and all advice and ideas appreciated greatly!
    Charles

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    What is the viscosity of the oil in the machine? What about the temperature of bearings, gearbox, etc. after several minutes at high speed?

    Paolo

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    If the motor plate says 8 amps, then that is what you go by just be sure you are reading the voltage on which you intend to run the motor as with lower voltage the size of the overload must be twice as much..What kind of bearings are in the motor? What shape are they in? Are they properly lubricated?
    If your motor plate says 8 amps full load and your motor is drawing 10, then your overloads are working correctly if they trip for overload protection of 8 fla...

    Overloads are always sized as closely as possible to the full load amps unless the starter is in another area where the ambient temperature is different from the machine in which case there is a compensation for the temp..

    Seems there is some reason that motor is overloaded at the highest speed...

    I have never encountered this problem with my 2hl but I never run it at top speed even with a vertical head installed...

    The standard hi speed head takes oil I believe in the spindle bearings and #1 grease everywhere else.. I have a std hi speed head for my 2h plain and that is how I lubricate it...

    Ramsay 1

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    Default Tripping Overloads

    I think I would consider installing run capacitors in the line with your idler motor....When I built my 5hp roto phase unit, I used two 440 volt run caps across the line and it made a big difference in the idling amps of the idler motor and also how my machines started..Also, this helped bring down the idling voltage of the generated leg a bit. I think it was figured at 12 - 16 mfd per hp per phase... That is, I used one 60 mfd and one 80 mfd across the three leads of the idler and it really helped.. The idling amps went from 12 to 4 on 220 single phase plus my machines started much better and faster.... Ramsay 1

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    Biolog, sorry looks like I missed your post...
    The heaters were used ones. But wouldn't a 10amp draw on one leg of a 8amp rated motor be the reason for tripping the overload? I don't remember now but when I went through sizing them, I stayed a little on the low side.
    I'm still learning about all this motor protection stuff...would it be common for an 8amp motor to pull 10amps safely and therefore I need to adjust heater size? And, if it is pulling 10amps now without a load other than high rpm setting, won't it pull a lot more under a heavy cut?

    Paolo, I flushed with kerosene and am using ISO 68 hydraulic fluid. At the highest speed that it will run without tripping overload, I let it run over an hour. I then placed my bare hand on the motor...warm but not "hot", on the gearbox/transmission and top of column area, again, slightly warm but not very.
    Before removing the universal head for all this recent troubleshooting, I was checking the head for temperature as I ran it with the original grease that was there. Not sure what it was they had in there, but seemed medium light viscosity. Before switching to a higher speed when I went to an insert endmill, the machine ran fine at the lower speed. And I had played around maybe hour or hour and a half at the lower speed. The head was slightly warm, and the grease thinned and a little accumulated around the spindle, and had a very small amount seep out around the top of the head, at a casting joint. Though it never really got "hot", I first suspected the grease was maybe affecting the "load" and causing the tripping, which is what lead me to pull it off and diagnose further. This thing really has me stumped now. Today I am going to rotate all three leads and see if the high current (or low current) phase follows the motor leads or stays with controller position. I checked resistance across the contacts by manually pushing them closed, and all read the same...think it was 1.4 ohms? Only thing else I might try that I haven't done yet is check voltage drop across contacts.
    If I don't figure this out soon, I may end up having to take motor to rebuild shop and let them test it...but I hate to spend money if it isn't necessary for something I can track down. But I'm running out of ideas!

    Ramsey, dataplate is 208v, 8amp. I sized based on the 8amp. Starter and disconnect are mounted on rear of column. The bearings on this Westinghouse are the oiled type, not greased. Oil reservoirs at rear of motor with tube running to front bearing. Small pipe plug on top. Not accessible on front with motor installed, but when I had motor out yesterday I pulled plugs and line and flushed some before refilling with oil. I am using the ISO 68 also for motor. I did notice a bit of endplay on shaft, but I don't think excessive. And when spinning motor by hand, it spun freely but I did notice a little "tinkling" noise...maybe like an oil slinger rattling around on the shaft? When I "hand checked" temperature as mentioned above, I also felt the bearing areas, and again, barely warm to the touch. Also made sure v belts were on the "loose" side.

    I will probably get around to adding capacitors at some point. My understanding of balancing at this point is pretty rudimentary. I thought the size ratio of idler to load motors made it "optional" in my case, but for sure it can't hurt to add them and try for better balance. The 5hp 2H and my bandsaw (don't recall HP...maybe 2 or 3?) have run just fine on it. This 2HL is giving me fits though!


    Appreciate everyone's input! You are all great! Please keep ideas and opinions coming! I'm wide open for any suggestions!!!

    Charles

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    Sounds like you have the exact same motor as I do...How much wear is in the front bearing? Be sure to tighten belts just to the point where they don't slip under load and no tighter as this will ruin front motor bushing....As mentioned before, I had to make a new bushing for the front of my motor ....I filled both of my bearing wells with oil from a zoom spout oiler as this is turbine oil.. I use this oil in all electric motors which take oil...

    On the vertical heads, some heat is normal after prolonged run but spindle bearings can be slacked just a bit for higher speeds...

    I think for the std hi speed heads, K&T shipped two grease guns, one for grease and one for oil if I am correct....No telling how many people used grease in the spindle bearings though over the years.. I know the std hi speed head I have was full of grease when I first got it.. Ramsay 1

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    Ok, the saga continues...
    Took motor to local motor rebuild shop, and had it checked out. It wasn't a teardown checkout but they megged it, checked voltage/load etc. And the gentleman that did it was "vintage" himself, so he was familiar with the motor and knew his stuff!
    He pronounced the motor "just fine"...the rattle was because I had oiled the front bearing, but not enough!! The slinger was dinging a bit. Learned that moderate overfilling won't hurt a thing on that type motor. Ramsey, I pulled the front bell off and cleaned and checked bearing while I had it on bench, and it's in very good shape.
    So if not the motor, then it is the load it's seeing at higher RPM. He mentioned belt depth in pully might create slight drag...looked like it had been running a little deep in pully. I replaced belts when I first got machine. Gates 3640. Is that the right belt?
    I took some time and compared the drag of spindle both freewheeling and in gear with my 2H. The 2HL is just as free. So the question is what could be causing this drag or load? The ISO 68 is the substitute for DTE Heavy Medium. Don't think that's the issue.

    Only two things I can think of at this point are:
    1. As mentioned in other thread on this 2HL, there are 6 feed speeds not working. Could something in the knee related to this be messed up causing the extra drag?
    2. I had to make a new bushing for the table feed shaft where it exits the crossfeed box. That is a bronze bushing that supports one end of the bevel gear that drives the table feed. I kept tolerance pretty tight on bushing. 0.001 clearance, and the diameter was a bit over 1"...don't remember exactly but maybe 1.250 max.
    Could this being a little on the tight side cause this kind of drag on a 3hp motor? I wouldn't think so but thought I'd ask those more knowledgeable than myself!!

    At this point, if I don't figure something out, my only two options are to run the mill as is and just don't utilize the higher speeds, or drop a 5HP motor in there in place of the 3HP. There is a local industrial supply that has several motors including a 5HP Baldor pretty reasonably priced. I really enjoy owning vintage machinery and would kinda like to keep it original as much as possible, but this may become my only choice on this mill.
    Thoughts?
    Charles

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    ISO 68 is not the problem probably.. I have run Exxon Nuto 68 in my 2hl for years without a problem....There is something causing that motor to overload and the problem with the feeds sends red flags up as far as I am concerned....On the bearing oiling, just put some in and don't worry about it as excess will run out and collect underneath the motor bracket..This is not nearly as critical as bearings which get grease and can leak into the windings and cause temperature rise and motor failure if the purge plugs are not properly used when greasing....

    I don't think I have ever had occasion to use the highest speed of my 2hl in the 20 plus years I have owned it...Cut some flats on a bolt recently with an endmill 1/4 inch four flute and the swivel head vertical head and probably ran the speed about half way maybe.. It did just fine...

    Your 2hl was designed to use a 3hp motor I don't think I would put a bigger one in it if it were mine..

    Ramsay 1

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    Well Ramsey, I have found a problem thanks to your advice. I spun the motor by hand with it out to feel for bearing problems...but I'm used to ball bearings! Never thought about the sleeve bearing and what wear there might be. I was thinking about your post and decided to investigate further, and sure enough, I pulled up and down on the shaft, and there IS quite a bit of wear. Could the rotor in the motor not being perfectly in line due to the wear in the bearing affect the motor output/load? Could this be causing some of my "load" issues?
    I had already put it all back together before finding the bearing wear...I will pull it out and make a new one before long. But while I had it all back together I did some more run testing. I put the head back on (still original grease)and ran it at 1088 for an hour. Then checked temperatures on everything I could. The bushing I made for the table feed shaft stayed cool, the transmission/column was barely warm. The head was warm enough to heat the grease to a thick oily goop (dripping out around spindle)...shot an infrared temp on the head and it was about 125 degrees. I assume this is normal for these heads? I could put comfortably lay my hand on it.
    So I guess fix the motor bearing, run it as is for now avoiding the higher speeds until I can find time to dive into the knee and see whats up with the feed. Getting ready to get busy at work so that may be a winter project!
    One other thing I found that I have seen you post about several times, is the spacer ring on the drive gear is gone. The bolt holes in the gear are gonna be a problem...one good, one broken bolt I can probably get out, two broken off deep and someone's buggered them up already trying to get them out. Those two are beyond my ability to get out. I assume gear is hardened and bolts aren't. Carbide drill, rotary table and peck? Or do I need to take it to someone with EDM? I'm not too knowledgeable on EDM other than read about it for removing taps and such. Can probably keep using as is as long as I make sure there is some backlash between the gears.
    If I somehow figure out how to get the two tough ones out, could you provide me the dimensions of the spacer ring so I can make one?
    Thanks!
    Charles

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    The wear in the motor bushing could be cause by prolonged use (remember, the bearing has less area in the upper part as there is a window machined in for the oil ring) or it could have been from someone running the belts with too much tension... My Westinghouse motor ran ok but I never used the top speed when I got it from the Navy...I could hear a bumping sound coming from the motor compartment so I investigated and found the wear in the shaft bearing on the output side of the motor.. New bushing fixed it.. It was a pain to make that new bushing as it has to have a flange on one side and a oil ring window as I recall but it has been many years since I made the bushing..I line reamed the new bushing when it was in place for proper fit to the shaft....I remember when I measured the shafts at each end, the pulley end measured .001 smaller than the dead end...

    The spacer disc is sized to the pitch diameter of the gear and coincides with the mating gear pitch diameter to insure proper backlash of the running gears.. Remember, there is nothing other than these two discs to insure proper backlash.. I have heard of people removing the disc to make it easier to install and remove the head but that is not good...

    One cannot install the drive bracket on the overarms and slide it into place.. The discs will not allow this.. You withdraw the overarms flush with the column then install the drive bracket over the drive gear THEN insert the overarms in the drive bracket....You could probably run the unit ok as long as you could insure that you had backlash between the gears but the disc setup is in there for a reason...(Ramsay 1

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    Chucky,
    Did you miss the post regarding balancing your RPC?
    Just because other machines run fine doesn't mean their motors are all running at equal amps on each leg.
    Balancing the phases of your RPC will probably correct your amp readings, fixing the bushing will correct the overload condition.
    If all you do is fix the bushing your motor may still trip the overloads and you also said your overloads were on the small side of 8 amps so change those out as well.
    I ran a very nice commercial made 15hp RPC for many years for all of my woodworking tools, it worked well and the voltages were within 1-2%.
    The more machines I ran at the same time the lower the amps for each machine.
    Good luck and hope you get her running well.

    Michael


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