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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Does this VIDEO depict a bad 3 phase motor?
I sold a supposedly rebuilt 3 phase 10 hp motor to a customer. The customer contacted me and is claiming that the motor is defective, citing vibration and noise. I asked him to make a video. As a proof of this, he produced the following video: https://www.youtube.com/watch?v=mn6bnva0Q0g As I watched it, and looking at the water in cup, I could not but feel that it is a totally normal motor. However, as I would like to be sure of whether I am right, or wrong, I wanted to ask your opinion. Does the above motor sound bad and does it vibrate excessively? thanks |
#2
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Does this VIDEO depict a bad 3 phase motor?
Ignoramus26205 wrote:
I sold a supposedly rebuilt 3 phase 10 hp motor to a customer. The customer contacted me and is claiming that the motor is defective, citing vibration and noise. I asked him to make a video. As a proof of this, he produced the following video: https://www.youtube.com/watch?v=mn6bnva0Q0g As I watched it, and looking at the water in cup, I could not but feel that it is a totally normal motor. However, as I would like to be sure of whether I am right, or wrong, I wanted to ask your opinion. Does the above motor sound bad and does it vibrate excessively? HUH? What is WRONG with the guy? The water is BARELY moving at ALL! I'm not sure the sound in a YouTube video is good enough to tell much, but it didn't sound wrong. If he wants a super-balanced motor, he's going to have to go to a Fanuc spindle motor or something. One doesn't expect a 10 Hp motor to "purr like a kitten". Also, if he's using a rotary phase converter or something like that, even though his L-L voltage is well balanced, the motor may have slightly more vibration than with a real 3-phase mains supply. Jon |
#3
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Does this VIDEO depict a bad 3 phase motor?
He has it mounted on a hard / semi-rigidity / wood pallet.
He should have it on shocks like an isolated rubber sheet without bolts through making the thing hard again. Rubber washers top/bottom with metal washers to transfer bolt head and nut to keep within bounds but not hold tight. Let the motor float in the bounds. If the need is so tight, then he should go multi-phase and super balanced with super bearings. The winding's have to be matched. Martin On 11/20/2017 8:32 PM, Ignoramus26205 wrote: I sold a supposedly rebuilt 3 phase 10 hp motor to a customer. The customer contacted me and is claiming that the motor is defective, citing vibration and noise. I asked him to make a video. As a proof of this, he produced the following video: https://www.youtube.com/watch?v=mn6bnva0Q0g As I watched it, and looking at the water in cup, I could not but feel that it is a totally normal motor. However, as I would like to be sure of whether I am right, or wrong, I wanted to ask your opinion. Does the above motor sound bad and does it vibrate excessively? thanks |
#4
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Does this VIDEO depict a bad 3 phase motor?
On Mon, 20 Nov 2017 20:32:29 -0600, Ignoramus26205
wrote: I sold a supposedly rebuilt 3 phase 10 hp motor to a customer. The customer contacted me and is claiming that the motor is defective, citing vibration and noise. I asked him to make a video. As a proof of this, he produced the following video: https://www.youtube.com/watch?v=mn6bnva0Q0g As I watched it, and looking at the water in cup, I could not but feel that it is a totally normal motor. However, as I would like to be sure of whether I am right, or wrong, I wanted to ask your opinion. Does the above motor sound bad and does it vibrate excessively? thanks Yes. It seems to have at least one bad bearing in it and at least one of the internal balancing weights ,( or more) has come up missing (if its not the type balanced by drilling away metal.. That is a decent quality motor. First thing Id do..is remove the rear endbell and roll it 90', reassemble, run..check for out of balance, roll another 90' etc etc..and see if one position makes it run smoother. Id also pull the stator and see if something is stuck in the stator..something that got the balance off. If it was rewound..they may..may have managed to get something jammed into the stator and its causing it to be out of balance. Its also possible that they broke something and its now out of balance. Ive seen rewind shops really **** up a simple rebuild job..which is why Im very...very careful about who I take motors to. Gunner --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#5
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Does this VIDEO depict a bad 3 phase motor?
On Mon, 20 Nov 2017 21:06:38 -0600, Jon Elson
wrote: Ignoramus26205 wrote: I sold a supposedly rebuilt 3 phase 10 hp motor to a customer. The customer contacted me and is claiming that the motor is defective, citing vibration and noise. I asked him to make a video. As a proof of this, he produced the following video: https://www.youtube.com/watch?v=mn6bnva0Q0g As I watched it, and looking at the water in cup, I could not but feel that it is a totally normal motor. However, as I would like to be sure of whether I am right, or wrong, I wanted to ask your opinion. Does the above motor sound bad and does it vibrate excessively? HUH? What is WRONG with the guy? The water is BARELY moving at ALL! I'm not sure the sound in a YouTube video is good enough to tell much, but it didn't sound wrong. If he wants a super-balanced motor, he's going to have to go to a Fanuc spindle motor or something. One doesn't expect a 10 Hp motor to "purr like a kitten". Also, if he's using a rotary phase converter or something like that, even though his L-L voltage is well balanced, the motor may have slightly more vibration than with a real 3-phase mains supply. Jon Most motors "today"...will barely generate any harmonic rings. While that is an older motor..its less than 20 yrs old..so it should be far quieter and smoother than that one. If the guy needs a super balanced motor...Wegg is quite good as are most Baldors, these days. That motor wouldnt pass for use on any CNC spindle in any machine I service. It would be ok on a chucker or DV69 or manual lathe..but..shrug...its pretty rough. Particularly for a 1725 rpm motor. Now I agree..if he is running it off a homemade rotary phase converter...its possibly an electrical issue..but my gut feeling..based on 20+ yrs of working with 3ph motors...its "not right" by any means. Gunner --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
#6
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Does this VIDEO depict a bad 3 phase motor?
On Mon, 20 Nov 2017 20:32:29 -0600, Ignoramus26205
wrote: I sold a supposedly rebuilt 3 phase 10 hp motor to a customer. So you're wondering if it's an Al Special rebuilt (blow off and repaint sans masking) or an actual rebuild? The customer contacted me and is claiming that the motor is defective, citing vibration and noise. I asked him to make a video. As a proof of this, he produced the following video: https://www.youtube.com/watch?v=mn6bnva0Q0g As I watched it, and looking at the water in cup, I could not but feel that it is a totally normal motor. However, as I would like to be sure of whether I am right, or wrong, I wanted to ask your opinion. Does the above motor sound bad and does it vibrate excessively? A 10hp motor with three or four tenths of vibration? Get out. That big guy is purring. There's a little something in the sound that bothers me on a minor level, but I'd want a stethoscope to verify that it's from one of the motor bearings and nothing else in the room. Just a harshness. I wonder if a screwdriver held against the bearing housing and up against the phone would pick anything up. -- Shake off all the fears of servile prejudices, under which weak minds are servilely crouched. Fix reason firmly in her seat, and call on her tribunal for every fact, every opinion. Question with boldness even the existence of a God; because, if there be one, he must more approve of the homage of reason than that of blindfolded fear. -- Thomas Jefferson |
#7
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Does this VIDEO depict a bad 3 phase motor?
Iggy, I'm no motor expert, but that one seems a little noisier than any of
the 3 phase motors I am running. Mine are all running on variable frequency drives though so the power delivery is very consistent. Some of the equipment some of my motors is connected to makes some noise, but when the drive belts are off they are pretty quiet. |
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