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builders board => General Builders discussion => Topic started by: Vortex 22 on February 21, 2022, 12:20:24 PM

Title: Rewind 3 phases motor for higher power rating?
Post by: Vortex 22 on February 21, 2022, 12:20:24 PM
Hi,
Is it really possible to
Rewind 3 phases motor for higher power rating ?

Assuming that we have 3kw power motor

It's possible to rewind that motor for higher voltage input
Say  we need a 10 kw motor?

Sorry, I know this no free energy but it's related subject!!!

Many Thanks
Regards
Vortex 22
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: pix on February 21, 2022, 12:26:33 PM
No.
Because this involves thicker windings, then deeper grooves in stator, larger stator ect.
Re-winding of small size 3 phase motor may cost the same like a new motor and is practiced when motor windings did burn.


Cheers,
Pix
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: Vortex 22 on February 21, 2022, 01:43:06 PM
Quote from: pix on February 21, 2022, 12:26:33 PM
No.
Because this involves thicker windings, then deeper grooves in stator, larger stator ect.
Re-winding of small size 3 phase motor may cost the same like a new motor and is practiced when motor windings did burn.


Cheers,
Pix

Maybe...
Many Thanks
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: Vortex 22 on February 21, 2022, 01:47:13 PM
I don't know for sure
But is it possible to rewind the motor using thinner wire and more turns?
For higher voltage input
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: pix on February 22, 2022, 06:47:29 AM
It is not simple like that.
Designing 3 phase motor involves many calculations because there are so many variables- number of poles, number of rows and the size,  rpm's, single or double windings, voltage ratings, motor rating for continous work, intermittent load, starting mode, VFD mode ect.
Generally rewinding is performed when it is economically sound, on bigger, expensive motors.
Smaller motors- it is better to buy a new one.
Month ago I was involved with modifying 3 phase squirrell cage motor with neodymium magnets and I gained some knowledge, spoken to people dealing with electrical motor repairs and rewinding.
Cost of rewinding 2,2kW motor exceeds price of a new one, at least in the city I live.


Cheers,
Pix
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: citfta on February 22, 2022, 07:27:11 AM
The confusion comes from the idea that higher voltage alone produces more power.  That is NOT true.  Higher voltage at the same current DOES produce more power.  BUT if you rewind a motor with smaller wire so that it will run at a higher voltage you have reduced the amount of current the wire can carry.  So you lose power from less current and don't really gain anything.  The engineers that designed the motor you want to rewind understand all that.  So they designed the motor to operate at a particular voltage and current.  You can rewind it for a higher voltage but because of the lower current the power out will probably be the same or less than the original motor windings.
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: Vortex 22 on February 22, 2022, 11:15:29 AM
Quote from: citfta on February 22, 2022, 07:27:11 AM
The confusion comes from the idea that higher voltage alone produces more power.  That is NOT true.  Higher voltage at the same current DOES produce more power.  BUT if you rewind a motor with smaller wire so that it will run at a higher voltage you have reduced the amount of current the wire can carry.  So you lose power from less current and don't really gain anything.  The engineers that designed the motor you want to rewind understand all that.  So they designed the motor to operate at a particular voltage and current.  You can rewind it for a higher voltage but because of the lower current the power out will probably be the same or less than the original motor windings.
Thank you Sir for the explanation!!!
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: Vortex 22 on February 22, 2022, 11:30:01 AM
In this site:
teslauniversedotcom

*EV Gray Motor vs Tesla Motor...*

A clear connection has been made between the radiant energy work of Nikola Tesla with the later (1973-75) work of Edwin Gray. It now appears evident that EV Gray knew a lot more about the Tesla Pierce Arrow car demonstration in Buffalo NY in 1931 than any of us involved in this new radiant energy area!

The similarities between the two radiant energy project specifications and detail are most remarkable.

Both used electric motors rated at about 80HP (Tesla's in his Pierce Arrow car and Gray's on a test bench). They also both used standard auto batteries (6V or 12V) for the power source for the radiant energy conversion process.
Both used special radiant energy conversion tubes. Tesla used twelve (12), while Gray used three (3) as described in the two EV Gray radiant energy conversion tube patents.
Both used matching capacitor banks rated at 5KVA each. Tesla used twelve (12), for a total of 60KVA (KW), while Gray used three (3) for a total of 15KVA.
The key design point for Tesla's car system was that his power rating of 60KVA equates to 80HP so that all of his design specifications match the full power rating for his car. How then, did EV Gray come close to achieving his 80HP rating?

We now know that he did this with a specially designed electric motor as the major innovation for EV Gray power system! There is no longer much speculation about this Gray design reality, because Norm Wootan of Texas, had in his possession motor #4 and #5 of Grays prototype motor series.

These EV Gray motors were shown at the KeelyNet meeting in June 2001. (Videotapes of that presentation are available from TeslaTech.) Since then a Canadian inventor has gained possession of them.''
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: Vortex 22 on February 22, 2022, 11:47:46 AM
Why
the motor used by Nikola Tesla in his electric car rated  60kw?
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: Vortex 22 on February 22, 2022, 12:19:12 PM
We can use in EV:
Battery + DC motor
Or
Battery + three phases inverter+ three phases ac motor
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: Vortex 22 on February 22, 2022, 12:26:27 PM
The higher input voltage the better  for the motor !!
380 v even in DC case
My best choice:
2000v to 3000 volts
Did you know where can I find a such Motor?
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: truesearch on February 22, 2022, 01:23:35 PM
It wouldn't be cheap but 3kv electric motors can be sourced from here:
https://www.menzel-motors.com/3000v-3kv/
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: Vortex 22 on February 23, 2022, 05:37:14 AM
Hello,

The company's prices are high
I am looking for a cheaper solution !!!

Thank you
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: Vortex 22 on February 24, 2022, 08:51:09 AM
Hi,

The materials used in the core should be soft iron not multiple Sheets of poor quality pressed tin shacked together.

Maybe that's the solution we are looking for
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: citfta on February 24, 2022, 09:47:30 AM


A solid soft iron core will get hot because of the eddy currents induced in it by the changing magnetic field.  If you are planning to run the motor on DC then you might get by with a soft iron core.  Where did you get the idea that a soft iron core was better than sheets pressed together?



Title: Re: Rewind 3 phases motor for higher power rating?
Post by: Vortex 22 on February 24, 2022, 11:47:54 AM
Quote from: citfta on February 24, 2022, 09:47:30 AM

A solid soft iron core will get hot because of the eddy currents induced in it by the changing magnetic field.  If you are planning to run the motor on DC then you might get by with a soft iron core.  Where did you get the idea that a soft iron core was better than sheets pressed together?
Hi,
One issue, how to make a commutators for the DC motor?

Maybe we should use homopolar motor design ?
High voltage switching? No brush, no commutators
I think it's can't be more simple than that!! Who's know
Title: Re: Rewind 3 phases motor for higher power rating?
Post by: Vortex 22 on February 24, 2022, 11:53:47 AM
Quote from: citfta on February 24, 2022, 09:47:30 AM

A solid soft iron core will get hot because of the eddy currents induced in it by the changing magnetic field.  If you are planning to run the motor on DC then you might get by with a soft iron core.  Where did you get the idea that a soft iron core was better than sheets pressed together?
Hi Citfta,
In my Overunity book, we don't care about the output section!!
We must kill the dipole here!!!
Regards
Vortex 22