Three phase motor burns out every three years ? WHY
Three phase motor burns out every three years ? WHY
(OP)
I purchased a Rotary Vertical Blanchard Grinder that has a 50 H.P motor that was originally wound for 3 phase and 50 hertz. I was told by the seller that I can run it at 60 hertz 3 phase without any problems. Over the last 6 years, I had the motor rewound two times and it costs thousands to rewind it, now it burned up again. The motor is an intregal part of the machine and can not be replaced with a new 60 hertz type. What can I do to prolong the life of the motor?





RE: Three phase motor burns out every three years ? WHY
RE: Three phase motor burns out every three years ? WHY
RE: Three phase motor burns out every three years ? WHY
______V.
______A.
______RPM
and what voltage you've been operating it on these past three years ... ?
Also, have you taken any current measurements when running it on 60 HZ supply ...
and, how much load (HP) are you running at ..?
Therein lie the answers .....
RE: Three phase motor burns out every three years ? WHY
Verification of proper specification and accurate response of the motor-overload relay by primary-current injection may be effort well invested.
RE: Three phase motor burns out every three years ? WHY
RE: Three phase motor burns out every three years ? WHY
As the others suggest you should provide much more information:
What are the exact motor nameplate data ?
How is the motor driven ? Direct, y/d, softstarter, VFD ?
What is the load ?
Measure the current in all three phases and over a long time.
In addition to the above, consider to have temperature sensors installed in all three windings. It will give you two advantages:
- Will tell you how the motor really is loaded.
- Will protect the motor so that you dont have to rewind it.
As you allready have to open the motor up in order to rewind it, you have a great opportunity to do it now !
Another possible cause of insulation break down, can be voltage spikes. Measure the voltage over a longer time.
Possibly install "snubbers" to protect against overvoltage spikes.
RE: Three phase motor burns out every three years ? WHY
And what will the efficiency tell you ?
RE: Three phase motor burns out every three years ? WHY
RE: Three phase motor burns out every three years ? WHY
RE: Three phase motor burns out every three years ? WHY
RE: Three phase motor burns out every three years ? WHY
RE: Three phase motor burns out every three years ? WHY
RE: Three phase motor burns out every three years ? WHY
RE: Three phase motor burns out every three years ? WHY
RE: Three phase motor burns out every three years ? WHY
RE: Three phase motor burns out every three years ? WHY
What type of process has this type of dynamics that would cause dangerous oscillations. What type of damage are you talking about. chronic or acute. I've put these on plastic extrusion, elevators etc without any apparent damage. Do you have a sourse reference?
RE: Three phase motor burns out every three years ? WHY
Not saying you are incorrect, Joseph, but you really do need to provide more information so that those who are not familiar with such consideration will be able to relate to your statement, understand what you mean, and have some guidance as to how to perform such an analysis.
Otherwise, Joseph, the statement in and of itself, provides no useful information and is hardly worthy of any consideration.
Kind of like telling a starving man to eat something ... without providing him any food.
You leave him with an empty stomach.
jΩ
RE: Three phase motor burns out every three years ? WHY
RE: Three phase motor burns out every three years ? WHY
Jbartos
What type of process has this type of dynamics that would cause dangerous oscillations.
///E.g. eccentric punch presses, and generally, any periodic engagement of load via mechanical clutches or electromagnetic couplings. This should not be difficult to identify for mechanical engineer or technician or handyman.\\\
What type of damage are you talking about. chronic or acute.
///I did not mention any damage. The electrical equipment or loads are often very well protected. Therefore, the word "dangerous may be interpreted in terms of tripping the circuit and load.\\\
I've put these on plastic extrusion, elevators etc without any apparent damage
///These types of loads tend to be better behaving loads for electrical motor, unless ten (? mechanical challenge) people start simultaneously jumping up and down in the elevator.\\\
Do you have a sourse reference?
///Visit
http://search.netscape.com/ns/boomframe.jsp?query=%22mo...
for:
Cyclic load insensitivity: HTS motor field windings operate at nearly constant temperature unlike conventional motors and, therefore, are not subject to thermal fatigue.
http://search.netscape.com/ns/boomframe.jsp?query=%22mo...
for:
Note: Current oscillations can also be caused by a cyclically varying load.
http://search.netscape.com/ns/boomframe.jsp?query=%22Ca...
for:
Studies in Dynamic Simulation and Analysis of Var compensators Feeding Cyclic Loads - A Feasibility Study of an AR model.(With G Govinda Rao, J Gopalachar and K Parthasarathy).
\\\
RE: Three phase motor burns out every three years ? WHY
So, JB, perhaps you'd like to suggest a methodology to use to perform such analysis ... rather than to just throw our such a statement without foundation or without sufficient explication that would make it useful.
///I beg your pardon Sir, this is the eng-tips Forum only, not to be confused with an Ivy League University site for students who pay in excess of $30000 per academic year. I do volunteer my posting and time. Therefore, I consider your comment inappropriate.\\\
Not saying you are incorrect, Joseph, but you really do need to provide more information so that those who are not familiar with such consideration will be able to relate to your statement, understand what you mean, and have some guidance as to how to perform such an analysis.
///How is one supposed to know a priory? Some other discipline engineers are more familiar with electrical engineering than many electrical engineers.\\\
Otherwise, Joseph, the statement in and of itself, provides no useful information and is hardly worthy of any consideration.
///I did not say that it did. But, it is a start.\\\
Kind of like telling a starving man to eat something ... without providing him any food.
///Of course Sir, everyone is entitled to ones own opinion.\\
You leave him with an empty stomach.
///It would be better if you contribute, rather than consistently criticized those who volunteer time and postings. Your postings of this nature are just wasting space and making threads harder to follow.\\\
jO