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Asset Condition ManagementPosts About Motor Testing
NO LOAD CURRENT UNBALANCE ISSUE
Registered Member I tested one 25 Hp L.V motor. In no load condition, the motor winding is showing 10% current unbalance.When I removed the rotor and do the current balance test for the stator winding,then found current unbalance only less than 2 %. Can someone explain this phenomenon. The supply voltage is balanced in both tests(less than 1 %) [ more ]
Registered Member Jan - Those are some fantastic experiments. This is very useful stuff imo. Where I work we occasionally take measurements, but we rarely have the opportunity to do controlled experiments where we vary one variable at a time to look at the effect. Regarding the unbalance experiment results that you posted 26 January 2010 07:24 PM – attached I summarized/analysed your results. In row 24, are the unbalances for each of 3 tests. The test with lowest voltage unbalance had lowest current... [ more ]
Registered Member It is not only the large DC current that creates the residual magnetism, as is shown below. And it is not the time that modifies the residual magnetism. The beauty of the following experiments is in the fact, that anybody can repeat them with very little effort. For the owners of the low voltage equipment, it is just few minutes exercise (if they have the guts to do it). I had a 200 hp, 460V, 1782 rpm, 223 Amp motor on the test bed for a load test the other day, so I had a chance to take a... [ more ]
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Asset Condition ManagementPosts About Motor Testing
Cryogenic Pumps(LNG Intak pump) Surge test fail
Registered Member Hello We always make these settings to the EARs of the surge test, as recommended by the manufacturer Megger baker: - LL EAR with rotor at 50%, due to the influence of the rotor - LL EAR without rotor at 10% - PP EAR always at 10% We always try to rely on the PP EAR, to diagnose, different responses between phases may indicate weak isolation between turns or shorts between turns, even when the comparison of waveforms comes out almost identical. I am attaching an example video of impulse... [ more ]
Registered Member I guess you may have tested the motor with the rotor still inside. The mutual inductance will cause the unbalance, quite common for what some people call a high influence rotor. Best to take the rotor out and re-test, cause a change in the rotor position will give a different P-P Ear value each time. Regards, Aditya [ more ]
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Asset Condition ManagementPosts About Motor Testing
High voltage winding test fails with the influence of rotor
Registered Member Thank you for the feedback! we will check the rotor centering and the clearance between the stator, also try to analyse or look at the closest possible points of contact to stator winding. [ more ]
Registered Member > Had there been some contamaination or debris found or some particles stuck in way of winding than when we test without rotor at that time also it should have been shorted to ground right? In my defense, I didn't know you checked again after disassembly, so I thought it could be slot section contamination or damage introduced during resassembly. ..But that scenario is ruled out since you found it good after removing rotor again (and stator slot section ground plane is relatively... [ more ]
Registered Member Thanks @electricplte for the reply. No.nothing has been changed since last test. Had there been some contamaination or debris found or some particles stuck in way of winding than when we test without rotor at that time also it should have been shorted to ground right? subsequently after test failed with installation of rotor and complete asembly, it was dimantled again and DC step voltage was carried out once again but test passed without any short to ground and leakage current found to be less. [ more ]
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Asset Condition ManagementPosts About Motor Testing
rotor bar analysis for motor operated valves?
Registered Member We can monitor changes in time-waveforms ! [ more ]
Registered Member If you are serious about MOV analysis, ask them to show you the Ultracheck M system. It uses thrust, torque, displacement, current & voltage sensors; required once to calibrate a valve. Subsequent analyses are done from current & voltage only. I believe it a big improvement over the old VOTES system from Liberty. Regards, Aditya [ more ]
Registered Member Thanks Aditya, that sounds like a promising lead. I fired them an email. [ more ]
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Asset Condition ManagementPosts About Motor Testing
VFD Issue
Registered Member Thank you for the response and sorry for the late reply, Please find the below answers for your clarification. 1.Unfortunately, test was not conducted on these equipment before due to which we are unable to do baseline comparison.. 2.Peaks are seen in both Voltage and current spectrum.(pls see below attached picture.) 3.There were no issues reported with the drive, as part of routine predictive maintenance equipment was being tested with Dynamic motor analyser. 4. Torque ripple is 69 %. [ more ]
Registered Member I am not very familiar with the Baker unit, but I know it is similar to the EMPATH that I use. Some questions rather than answers: 1. Have these peaks been there from the beginning or just showed up? 2. The torque/power spectra are inherently demodulated. Are the corresponding peaks (± line frequency) showing up in current only or also in the voltage? 3. Do you have any reported issues with the drive, motor or load? 4. What is the ripple percentage? Regards, Aditya [ more ]
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Asset Condition ManagementPosts About Motor Testing
Increased current unbalance at reduced load
Registered Member Assume this motor is fed from an MCC, do other motors fed from this MCC also show current imbalance? Are the wires from the MCC to the motor the same size? Fuses are the same size? Is there a disconnect between the MCC and the motor? Have you done a voltage drop across the circuit breaker/contacts/fuses/overloads/knife switch? This will identify if there is a high or low resistance connection in the MCCC. Have you taken resistance readings from the MCC to the motor? Is the motor acting... [ more ]
Registered Member Thank you @Registered Member for your reply. Calculated voltage unbalance (max % deviation from mean of rms) for both the load conditions are same around 0.2%. What does the data show, any electrical issue in phase-2 or it can be considered as normal ? [ more ]
Registered Member It sounds like a voltage unbalance problem to me. In the presence of unbalanced voltage, the magnetizing component of the motor current is highly unbalanced while the load component is balanced. When you add them together at high load it averages out and looks like a small imbalance in current. When you reduce the load level, the balanced load current goes away / decreases and the total current starts to look more like the magnetizing component, which is highly unbalanced. [ more ]
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Asset Condition ManagementPosts About Motor Testing
Predictive in motors
Registered Member MCE abbreviation appears to be used exclusively by PdMA. MCSA motor current spectrum analysis (operating motor from current or vibration or flux) MCE motor circuit evaluator (operating, offline, disassembled) (PdMA) MCA motor circuit analysis (operating and offline) (All-Test Pro) ESA energized signature analysis (All-Test Pro) DMA dynamic motor analyzer (SKF-Baker/Megger) There are many types of motor electrical and mechanical tests that depend on product capability and situation... [ more ]
Registered Member https://alltestpro.com/ https://www.skf.com/binary/21-...Motor-PdM-primer.pdf http://www.pdma.com/about-PdMA.php [ more ]
Registered Member Its a tecnology for detect problema un rotor, ir estator... [ more ]
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Asset Condition ManagementPosts About Motor Testing
Reg; Motor vibration is fluctuation
Registered Member Is fluctuation random or sinusoidal ? If its sinusoidal, confirm if its 2x line frequency. If it is, its due to faulty motor (loose, damage or broken rotor bars etc.) PS: This post is so old, but I commented because some body might take help from it. [ more ]
Registered Member jvoitl, This motor may have a mechanical issue, but it is being manifested by a beat against the electrical energy. This post is fine where it is. vel_reliable, Check the time of the beat frequency. Then look at a high resolution fft of the vibration, especially around 2x line frequency. See how many sidebands you have and check to see if they are equal to the # of poles times slip (slip is the difference between the field speed and the rotor speed). The more sidebands, the more likely you... [ more ]
Registered Member Vel, The MNDE amplitude is the axial or the radial amplitude? Can you show me the FFT? Thanks! [ more ]
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Asset Condition ManagementPosts About Motor Testing
MCSA
Registered Member MCSA by itself if we're talking about the frequency spectrum is good for two things. First you can look for rotor bar damage by looking for subharmonics and their relative peak heights. This is much better than the offline test (rotor influence testing) that tells you if a rotor bar issue is present but not severity...it might be nothing such as a small casting defect but the rotor influence test finds anything not symmetrical, and it's a visual test only. Second thing is that you can look... [ more ]
Registered Member A clamp-on current transformer needs to have a voltage output with good frequency response. I use an inexpensive Fluke clamp-on (now quite old) with a home-made resistor box (typically 10 to 20 ohms) to get volts output. Make sure the analyzer is set to voltage input and not ICP voltage turned on (accelerometer). There is plenty of good information on Internet about MCSA. Make sure you have basic electrical training (or have assistant) when making the measurements. You can be successful at... [ more ]
Registered Member Hi Masood, Yes. You can use VibXpert II for MCSA testing and analyzing. However, it will be better if you have CSA tool for evaluating electrical faultzones of motor/generator. Because, beside you can analyze squirrel cage rotor condition, you are also capable for knowing the condition of air-gap, stator winding, power circuit, power quality... of motor/generator. We are using MCEmax of PdMA, and get highly effeciency in our CBM program. Regards, Lampard. [ more ]
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Asset Condition ManagementPosts About Motor Testing
Maximum Allowable Temperature Rise for class F Insulation?
Registered Member Its seems this is truly one of the cases mentioned. Thank you. At the place where I work, it is a bit hotter than other places. For this reason, the ambient is not 40 C, as an exception. Orders are supplied with 50 C modification to the default standard paragraph. Regards- Ali M. Al-Shurafa [ more ]
Registered Member 115C is specified in NEMA MG-1 as the maximum temperature rise for a continuous duty motor with service factor 1.15 or higher, in a 40C ambient. You might roughly interpret this to indicate that the insulation temperature limit is 115+40 = 155C at the service factor load. It's not quite that simple/exact. For lower service factor, the max rise would be 110C at full load. Also the associated temperature measurement is generally considered an average temperature if temperature is measured by... [ more ]
Registered Member Interesting. Can you please explain this result? Regards- Ali M. Al-Shurafa [ more ]
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Asset Condition ManagementPosts About Motor Testing
Rotor bar fault
Registered Member Nice report. I like the format. I'm not familiar with your equipment so I cannot really comment on the diagnosis. However, I've noticed two things in the report. 1. The frequency spectrum at the end of the report is given in g rms. I do not use g for low frequencies. 2. The speed of the motor is too low to me. The slip is about 4.8% if I did the calculations correctly. Healthy motors in my world never reach this slip. Regards- Ali M. Al-Shurafa [ more ]
Registered Member The other thing the baseplate is flexible. it does not touch the ground. [ more ]
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Asset Condition ManagementPosts About Motor Testing
Value/Condition of % Inductance Imbalance HELP
Registered Member The output from a Baker surge test is the oscillating frequency which can be directly related back to the coil inductance. Lots of people use the graphical output and try to interpret it in various ways but the fact is that we're just seeing oscillations from an underdamped LC tank circuit that is smacked with a good size voltage stored in the capacitor. The charge voltage is within a fraction of the limits of healthy insulation which hopefully the Baker tester screened out using a megger... [ more ]
Registered Member We actually don't use PDMA, but I'm interested in it. Commeting based on my limited understanding. [quote]Theoretically this test should be equivalent to the Baker surge testing. I haven't been able to document enough cases yet to conclusively prove that one test is superior to the other. [/quote] I guess you're saying they're equivalent from the standpoint they are both intended to detect turn to turn shorts. In that respect I'd point out an obvious difference. Surge testing creates a... [ more ]
Registered Member I've been down this rabbit hole countless times. PdMA themselves says they've seen it as high as 20% on an otherwise perfectly normal motor. I've seen values up to 15% even brand new in the packaging in the warehouse. Doing all that other testing finds nothing every time. If I see anything up to 15% unless it's out of trend, I ignore it. At 20% and higher, that's a different problem. Impedance (online testing) usually fails too and eventually we'll find something else wrong but unless there... [ more ]
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Asset Condition ManagementPosts About Motor Testing
eletrical discharge in DC motors
Registered Member I see what the real problem is. Ours is the older documentation linked below. The newer documentation clearly states that it's the number of discharges that it detected in a given time period that it measured (say 10 seconds). That number doesn't mean anything to anybody. http://www.vibescorp.ca/learn-...haft-currents/#tked1 https://docs-emea.rs-online.co...0900766b8124caf9.pdf [ more ]
Registered Member [QUOTE]…electromagnetic type partial discharge measurement devices they nuts around the commutators of DC motors because by nature the commutator is continuously sparking at levels far above that partial discharge meters are meant to detect. You have to switch to another measurement technology to overcome this. My suspicion is that the SKF meter (we have one in the shop) is similar in nature...it gets swamped by the extreme sparking RF produced by normal operation of a commutator. My... [ more ]
Registered Member I doubt it's the sensor's fault. When you use the electromagnetic type partial discharge measurement devices they go nuts around the commutators of DC motors because by nature the commutator is continuously sparking at levels far above that partial discharge meters are meant to detect. You have to switch to another measurement technology to overcome this. My suspicion is that the SKF meter (we have one in the shop) is similar in nature...it gets swamped by the extreme sparking RF produced by... [ more ]
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Asset Condition ManagementPosts About Motor Testing
SLIP RING ROTOR BUS BAR MELTED
Registered Member First off, this is a synchronous or wound rotor motor (not specified which). These are very different from induction motors. You treat both of them the same way. First look for physical damage. Is any of the wiring stretched out of shape like it was ripped apart by something mechanically? If not, move on. This is rare but it does happen occasionally. It is very obvious because the wiring gets stretched and distorted, tie downs ripped apart, etc., with little heat damage. Move on to checking... [ more ]
Registered Member We can know this problem in the early stage by using MCSA or resistance testing. We have some case study of rotor winding with high resistance connection or problem of carbon brushes. Lampard Nguyen [ more ]
Registered Member UPLOADED AGAIN [ more ]
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Asset Condition ManagementPosts About Motor Testing
current clamp
Registered Member The Omega units above are very good. However, they use Hall effect technology to measure both AC and DC current. Unless you have a specific need for DC I would look for something else. Hall effect units can be a little touchy if you're not experienced with them, and even then putting them in a different plane from where they were zeroed can give an erroneous reading. [ more ]
Registered Member Hi...i am a new user here. As per my knowledge your vibration software and select the proper scaling for the sensor you are using. If you are reading off ct secondary you can also set up the scaling so that everything displays in ct primary units. [ more ]
Registered Member El'Pete, Looks like this product line should provide AC current as a voltage signal (waveform and spectrum) with available BNC adapter, as you indicated. http://www.omega.com/temperature/pdf/HHM70.pdf Walt [ more ]
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Asset Condition ManagementPosts About Motor Testing
Rotor broken bar problem or variable load or vibration issue cause sideband around line frequency on current FFT spectrum?
Registered Member Hello ADITYA, Your comments are always very enlightening, i am a beginner in reliability and motor diagnostics. i will appreciate if i could have you as a my guild should the need arise. orugbosamuel@gmail.com many thanks. [ more ]
Registered Member Cando Based upon the signatures, you are using a PdMA tester. Concerning the 'swirl effect,' at this point they are the only ones using this as part of their diagnosis. In my experience, I have not really seen it with the technologies I use, with broken rotor bars. In your top example - Even if one of the sidebands fell around PPF, the sidebands around the line frequency appear to be more related to harmonics of the first peak sidebands around the line frequency. What is the context of this... [ more ]
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Asset Condition ManagementPosts About Motor Testing
Cast rotor - worsening current signature trend, no change in vibration
Registered Member Hi Pete I couldn't download attachment can you mail it please. orugbosamuel@gmail.com thanks. [ more ]
Registered Member ElectricPete I have not had a chance to look through most of this post. However, based on the original slides I would suspect that you may have some fractures in the cast rotor. The PPF (Pole Pass Frequency) will vary with load (2x Slip Frequency). If you are taking the data from the machine CTs, sometimes this will also dampen the peaks or cause the sidebands to vary a little - non-linear to load. Rotor bars will primarily cause a torsional vibration, so may not show up significantly in... [ more ]
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Asset Condition ManagementPosts About Motor Testing
Predictive motor testing in the field
Registered Member its a great to be part of this discussion. great ideas and information shared here. I will like a personal instructor on Electric motor reliability. i cannot afford any training at the moment. orugbosamuel@gmail.com. Thanks you all for your contribution. [ more ]
Registered Member I haven't used the models you have, but they all have decent specs, so it looks like you are covered there. I've seen some low-voltage windings that had not yet failed, but had insulation that — although technically meeting specifications — had weak insulation which could be seen with any decent megger by simply watching the bar graph for an uneven climb over, say,a five-minute period. Unfortunately, such cases are the exceptions, rather than the rule. Are they especially known for their tan... [ more ]
Registered Member Metrel MI2077 (5 kV), Metrel MI3200 (10 kV) & Megger MIT525 (5 kV). All of them do IR, DAR, PI, SV & DD; good for MV motors (mica based insulation) but do little to qualitatively assess LV motors (enamel based insulation). Maximum measurement at 1000 V: MI2077 - 1 Teraohm MI3200 - 1 Teraohm MIT525 - Not specified; but 10 Teraohm at 5 kV Another question often asked by clients - how to ensure the rewinder used good quality copper wire? For the enamel; someone suggested trying low... [ more ]
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Asset Condition ManagementPosts About Motor Testing
Rotor broken bars?
Registered Member Dear all, Thank you so much for your recommendations. I have just performed RIC (rotor influence check) for this motor. RIC profile indicates some erratic relate to rotor broken bar issue. I think that there is problem of rotor. It's a interesting case-study! Thank you! Best regards, [ more ]
Registered Member Lampard, like Dave said you must cut spectrum or Fmax. should be at 5-6 speed of motor to see good patern and good haystaks . At figure 6 it should be rotor bar pass frequency pick at 1470 Hz and one pick left like twice line frequency sideband . Good luck . [ more ]
Registered Member To diagnose rotor bar problems in vibration spectrum: Identify actual running speed and subtract it from synchronous speed 1800-1775=25 rpm of slip, now multiply the slip rpm X the number of poles in the motor 4 poles x 25=100 cpm pole pass sidebands IF the motor truly has a rotor bar problem, then you should see the pole pass sidebands around 1x 2x 3x 4x 4x 5x rpm or some combination of the harmonics. Keep in mind your bin spacing on spectrum, you must have good resolution to see these... [ more ]
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Asset Condition ManagementPosts About Motor Testing
Which tests are worthwhile
Registered Member As stated by others, depends on what type of equipment you are using or plan to use. Resistance phase to phase and each phase to ground, capacitance to ground, inductive imbalance are all good tests on electric motors. https://www.easa.com/resource_library http://www.nema.org/Standards/...s/pages/default.aspx https://www.nema.org/Standards...-and-Generators.aspx Above are some additional resources that could be of value Dave [ more ]
Registered Member I totally agree with the statement above. You need to check resistance, insulation, windings as well as any other factors your tester will give you information on. The more the merrier. And absolutely tag each motor with the results. Additionally keep a copy of the results in a secure place as tags do get destroyed and rendered illegible. You might find the linked case study helpful. http://cstsolutionsllc.com/wp-...agner-Case-Study.pdf Steve Oberstein Copperstate Technical Solutions [ more ]
Registered Member If you're going to the trouble to hook up a motor tester, Baker, PdMA or whatever, why not just run all the tests it's capable of and not worry about it, only takes a few minutes? I also put a note on the motor to be informed where it is used in the future so I can use the test as a baseline. [ more ]
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Asset Condition ManagementPosts About Motor Testing
Demodulation of motor current in CSI 2130
Registered Member This information is based on my CSI 2120-2 analyzer for Off-Route Mode: Select Bandpass PreFilter 50 to 300 Hz for 2x Line Frequency and either 100 to 600 Hz or 500 to 1000 Hz for rotor bar and stator slot frequencies. Note that the selected filter frequency must be equal to or greater than the specified maximum frequency of the analysis. The Demodulator attachment for the old 2110 analyzer had additional settings. Good luck with the 2130! Walt [ more ]
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Asset Condition ManagementPosts About Motor Testing
Motor/Pump issues
Registered Member It's difficult to tell if the sound is abnormal, because we don't know what it sounded like before. I hear the tell-tale whine of a VFD carrier frequency (the rate at which the tiny little DC pulses fire), but if this is above and beyond that, you may have EDM damage to your bearings because of the VFD output and poor grounding. EDM damage is the result of a voltage build-up between the stator and rotor as a result of the high frequency pulses from the VFD causing what's called "common mode"... [ more ]
Registered Member Hi y'all, You're right at 20% there is no flow and in fact here in Europe with 50 Hz it's only 1500 rpm (1455 on the plate). I was only running it this slow (essentially just the motor - removed pump casing, impeller, and m/seal but there is what Alfa Laval calls an adapter instead of a coupling that I left on) because the noise is quite evident even at this speed. When you say noise from the VFD, I'm a little unaware of what you mean... I'm definitely still learning the practicalities of... [ more ]
Registered Member I am surprised that you are trying to run a centrifugal pump at 20% speed and get any flow out of it. If the motor nominal speed rating is 1800 RPM, then 20% speed is only 360 rpm. It would be a little difficult to listen for bearing noise at such a low speed; especially with the electrical noise from the VFD. I'm also not sure what you mean by taking the head off the pump running it. If the motor bearings have not been lubricated in years, and with the wrong grease, then how can one assume... [ more ]
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Asset Condition ManagementPosts About Motor Testing
Motor Troubleshooting Guide Flowchart
Registered Member Thanks ElectricPete for sharing the manual. More details is what most people commented. It appears most who review, are expecting our particular flow chart to be a replacement for the manual and/or training. Which is never the case for any flow chart, that is why you always see flowcharts and troubleshooting sections at the end of manuals. Thanks for giving me an idea for popup alert when people first stumble on to the flow chart who may not be as experienced as you. I'll check into adding... [ more ]
Registered Member I think it is better to learn the fundamentals and then apply logic to your situation, rather than trying to learn a flowchart. I also agree that in the heat of battle, a flowchart may in theory be a helpful tool to doublecheck if you might have overlooked something. There is already a very detailed motor troubleshooting guide freely available here http://www.epri.com/abstracts/...68&Mode=download …Particularly appendix B - look up the symptom and it suggests particular causes to consider. [ more ]
Registered Member Thanks Walt. That is what i was referring to when I asked if it would be worth it to, "built out with additional information". From your valuable feedback, I do not know if it would be worth it, to build it out, but am getting a consensus from everyone's feedback. The consensus appears to be, it is not very useful in current state (except for possibly the beginner) and needs built out more just to be of value to a wider audience . My original thought when I had the designers make it, was to... [ more ]
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Asset Condition ManagementPosts About Motor Testing
MCSA
Registered Member It is always better to measure the actual speed and line frequency at the same time. This will give clear idea. [ more ]
Registered Member Harpreet , If you are in * 50Hz* land and nominal speed at nameplate for 4- pole motor is 1480 rpm under nominal load I think perhaps 1490 rpm is his real speed under 60 percent load . Meybe it is reason why is pole pass freq. is at half values . Good luck ! [ more ]
Registered Member Motor was at about 60% load. But why should one half of polepass freq side bands appear due to less load?? [ more ]
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Asset Condition ManagementPosts About Motor Testing
Babbitt Bearing Repair
Registered Member Hopefully he did because this thread is 4-1/2 years old! [ more ]
Registered Member Have you completed the upgrade? This might not be of use for you now, but I found it interesting. This is a video that I found in YouTube that explains the UT testing of Babbitt bearings. The UT testing has evolved over the time. [ more ]
Registered Member I just downloaded and looked at the DOD spec John posted.........get you a KrautKrammer and call Ultron for training! LOL The procedure in the DoD doc is pretty simple. If you buy a box, don't skimp on the transducers. A dual transducer is probably what you want. Don't go with a cheapy, they will have all kinds of noise that will look like the bang (shown as IF in the pdf) everywhere. I still have a couple of them lying around somewhere. Aren't worth even finding again! Good luck. D [ more ]
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Asset Condition ManagementPosts About Motor Testing
Voltage notch depth in MT circuit
Registered Member There are 6 equally-spaced notches per cycle. So this is associated with commutation of the 6 electronic switches in a three phase full bridge converter (example rectifier bridge or SCR bridge). It is either an electronic converter upstream of this motor (dedicated to the motor or maybe to a larger bus that includes the motor) or an electronic converter powered from the same bus as this motor. Either way it does not indicate any problem of the motor itself. Also it generally does not... [ more ]
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Asset Condition ManagementPosts About Motor Testing
Motor 250 kW with V6 mounting
Registered Member The amount of shaft end play is going to be dependent on the fit class of the Angular Contact (thrust) 7319 bearing. A CA fit will have the least shaft end play, a CC fit will have the most. For the 7319, the axial clearances are: CA - .0006" to .0010" CB - .0013" to .0017" CC - .0022" to .0026" The fit class of the bearing is important to know to assess this issue. The 7319 ODE bearing will be the determinant of shaft end play along with any preload applied. [ more ]
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Asset Condition ManagementPosts About Motor Testing
MCA and ESA
Registered Member Although All Test Pro, Baker and PDMA will work for your application, I prefer All Test Pro for its ease of use and portability http://cstsolutionsllc.com/shop/all-test-pro-5/ . The ATP 5 is simple and quick to both learn and operate. Best regards 'Steve [ more ]
Registered Member All Test Pro and Pdma are both great options. Baker goes for surge testing which isnt a great idea for aged in-service machines. You dont want to fail a weak winding that could have lasted for couple of years. [ more ]
Registered Member I would look at the Pdma MCE tester, it is what we use in the field to evaluate and trend customer motors. The SKF Baker tester is more a shop tool, larger, bulkier, and more difficult to handle in the field. [ more ]
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Asset Condition ManagementPosts About Motor Testing
Test requirement of coupled motors in a new petrochemical plant construction site.
Registered Member NETA Acceptance Testing Specifications can form a minimum acceptance criteria. NETA ATS-2013 is available from : www.netaworld.org [ more ]
Registered Member I would rather emphasize on what is bounden between you and the other parties. The contract usually is the primary reference. What you may find acceptable and fair might not be for the others. For them, it might be too little or too much based what they agreed on with you. Many times, contacts are not detailed enough and they usually refer the parties to other references. You may end up with API, NEMA or I SO but I cannot assume. Good luck. Regards-Ali M. Al-Shurafa [ more ]
Registered Member Thank you Mr. HOWARD [ more ]
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Asset Condition ManagementPosts About Motor Testing
storing motors
Registered Member If the Stores/Procurement organization does not desire to allow maintenance technicians into the store room to rotate motor shafts and measure insulation resistance periodically, then they must be trained and tasked to do so. The "maintenance" being done in this case is the preservation of the value of the stored asset, and the Stores organization is directly responsible for that by maintaining proper storage environment/conditions and doing what is necessary to ensure the stored spares are... [ more ]
Registered Member Not always, process chemicals, raw materials, stuff for engineering and construction also use the stores/procurement infrastructure [ more ]
Registered Member Ultimately everyone exist to service the Company. Would you agree that the biggest customer for the materials dept is Maintenance dept? [ more ]
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Asset Condition ManagementPosts About Motor Testing
Alltest Pro Compatibility with EMERSON
Registered Member Software incomparability is a common issue in reliability. Each manufacturer wants everyone to use nothing but their software and it quickly becomes an IT nightmare. Now most of these programs are well thought out and do a very good job. However they generally do not work well with other manufacturers equipment. Might I suggest you look at a asset management program such as DMSI Maintelligence. It can take data from pretty much all sources and combine it into one report. You can check it out... [ more ]
Registered Member Hi Walt, Thanks for your input. Actually client wants to handle only a single software for motor offline & online testing with VA program. They do have current clamps. but they want to improvise Motor Testing but afraid to have 2 different OEM software for data management. I do not know the file type of ATP tool. If it is CSV file, life would be easier. I have told them to do it separately to get maximum output rather than to find easiness . But fingers crossed, maybe there would be any... [ more ]
Registered Member I have never seen either product advertised as being "compatible". You could utilize "Note Codes" and Manual Data Entry Points with the CSI analyzer and use the CSI software for Trends and Alarming. What are you trying to do, and what is your expectation of using both together? The CSI analyzer can do MCSA with a clamp-on current transformer; without the need for the ATP. Of course the ATP has a lot of features dedicated to motor current spectrum analysis. Walt [ more ]
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Asset Condition ManagementPosts About Motor Testing
Cable terminal torque requirement
Registered Member The recommended torque specification should be available from the manufacturer of the starter that the motor is connecting to. At the motor end, it should be a lugged connection and the fasteners should be torqued to nominal value for their size and grade. Torque charts are widely available on the internet and from fastener suppliers. Michael Meehan, CMRP, CRL [ more ]
Registered Member Thanks [ more ]
Registered Member Torque specs have to do with bolt size and type, not with cable size, and are readily available on the internet. [ more ]
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Asset Condition ManagementPosts About Motor Testing
current fluctuation
Registered Member Hello RAYMUNDUS , Can you give me namplate motor RPM or number of motor poles? If your motor has 4 poles, 0.02Hz vibration can cause 0.04Hz fluctuation in motor current. In my oppinion, this case is of your Preheater damage, broken impeller. High unbalance will cause high fluctuation of current. Good luck! [ more ]
Registered Member Have you checked whether it might be pole pass frequency? (example 3598.8 rpm on 2-pole 60hz motor has pole pass frequency 2*1.2 cpm = 2.4cpm = 0.04hz... would have to be a large and/or lightly-loaded motor) [ more ]
Registered Member Yes, i have simple analysis related to my problem, the rotation speed is 1.14 rpm, so the period is approach to 52.63 s, the period of the fluctuation is 26 s, 1/2 rotation period. So i think that fluctuation is in the seal gap clearance that not properly adjusted. Radial seal is located on the 0, 180 and 230 degree... [ more ]
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Asset Condition ManagementPosts About Motor Testing
How Liquid Starter Works?
Registered Member If you have parallel electrode plates in an electrolytic solution, you can vary the resistance by varying the separation distance between those electrode plates. This finds common application as the variable resistance for use in rotor circuit of large wound rotor motors. Plates start far apart for high resistance at beginning of start and are moved closer together during the course of the start to reduce resistance. [ more ]
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