Copyright 2015 Maurice E. Heskett, all rights reserved.
I had printed out something I had an interest in a few days ago, and when
I picked it up just now, I see a very disturbing to me, notice at the
bottom of the last page saying
CopyRight 2015 GitHub, inc.
No wonder I am seeing derogatory r
On Sunday 14 June 2015 21:03:40 Dave Cole wrote:
> Squirrel cage motors driven by VFDs slip. The motors have to slip to
> magnetize the rotor. If you want tight control of a Squirrel cage
> motor (as tight as possible) they put a encoder on the motor then run
> the motor in vector control mode
Gene,
I don't think the torque falls that quickly with a V/Hz VFD. There are
some curves in the pdf below.
https://www.google.com/url?sa=t&source=web&rct=j&url=http://literature.rockwellautomation.com/idc/groups/literature/documents/wp/drives-wp002_-en-p.pdf&ved=0CC8QFjAFahUKEwjo7qHsxJDGAhUGWJIK
Squirrel cage motors driven by VFDs slip. The motors have to slip to
magnetize the rotor. If you want tight control of a Squirrel cage
motor (as tight as possible) they put a encoder on the motor then run
the motor in vector control mode, where the slip is compensated for by
the drive. But
On Sunday 14 June 2015 17:32:07 andy pugh wrote:
> On 14 June 2015 at 17:14, Gene Heskett wrote:
> > So how do we discern the induction motor,totally unsuitable for vfd
> > drive except near is design rpms, from the synchronous motor at home
> > on a vfd drive?
>
> I think there is a false assumpt
On 14 June 2015 at 21:08, Marius Alksnys wrote:
> Does anybody know BLDC motor drivers suitable to run BLDC servo motor:
> rated at 230W, 48V, 8 poles, 3000 RPM?
Both Pico and Mesa do drivers that are suitable.
http://pico-systems.com/osc2.5/catalog/product_info.php?cPath=3&products_id=20
http://
On 14 June 2015 at 17:14, Gene Heskett wrote:
> So how do we discern the induction motor,totally unsuitable for vfd drive
> except near is design rpms, from the synchronous motor at home on a vfd
> drive?
I think there is a false assumption here. VFDs are _intended_ for
driving induction motors.
On 14 June 2015 at 12:55, Steve Stallings wrote:
> Andy, that is a nice looking setup. I see what I think
> is a rotary joint in the head block. Is that factory
> or shop made?
It's home-made (on the machine itself). It was required for the hobbing setup.
> Is it essential to the clearance neede
On Sunday 14 June 2015 16:08:22 Marius Alksnys wrote:
> Does anybody know BLDC motor drivers suitable to run BLDC servo motor:
> rated at 230W, 48V, 8 poles, 3000 RPM?
>
> I want to control the motor using one PWM and three hall signals or
> three phase PWM.
>
> Has anybody succeeded running some s
Does anybody know BLDC motor drivers suitable to run BLDC servo motor:
rated at 230W, 48V, 8 poles, 3000 RPM?
I want to control the motor using one PWM and three hall signals or
three phase PWM.
Has anybody succeeded running some simple BLDC drivers for that?
Maybe one of these would have fast
Here are some new Nema 48's from Baldor.
http://www.electricmotorwholesale.com/BALDOR-MOTORS-3PH-DP.html
Here is Siemens standard motor catalog - if you look at page 2/10 you
can get an idea of the IEC/Metric frame sizes and relative power outputs.
http://www.motology.co.th/download/motors/%282%2
On Sunday 14 June 2015 10:54:57 Dave Cole wrote:
> Gene,
>
> Try looking for a Nema 48 AC motor. They are almost an inch smaller
> in diameter.
That makes perfect sense. But no search hits until I drop it to Nema 42.
> Also, there are some metric frame motors that are common in Europe
> that a
Gene,
Try looking for a Nema 48 AC motor. They are almost an inch smaller in
diameter.
Also, there are some metric frame motors that are common in Europe that
are also smaller in diameter than a Nema 56.
http://kurz.com/wp-content/uploads/2014/09/Baldor-NEMA-Frame-Chart.pdf
http://www.engine
On Sunday 14 June 2015 09:49:33 Kirk Wallace wrote:
> On 06/14/2015 04:48 AM, Steve Stallings wrote:
> >> -Original Message-
> >> From: Gregg Eshelman [mailto:g_ala...@yahoo.com]
> >> Sent: Sunday, June 14, 2015 4:12 AM
> >
> >
> >
> >> If it has a 240 option on both primary and secondar
On Sunday 14 June 2015 05:06:22 andy pugh wrote:
> On 14 June 2015 at 02:38, Gene Heskett wrote:
> > It does look good, but where can I get an adaptor to mount that 56C
> > frame on the GO704? Or is that my first project, making one? ;-)
>
> What is the existing motor mount?
About an inch smal
On Sunday 14 June 2015 05:06:22 andy pugh wrote:
> On 14 June 2015 at 02:38, Gene Heskett wrote:
> > It does look good, but where can I get an adaptor to mount that 56C
> > frame on the GO704? Or is that my first project, making one? ;-)
>
> What is the existing motor mount?
> I adapted my Mini
On 06/14/2015 04:48 AM, Steve Stallings wrote:
>> -Original Message-
>> From: Gregg Eshelman [mailto:g_ala...@yahoo.com]
>> Sent: Sunday, June 14, 2015 4:12 AM
>
>>
>> If it has a 240 option on both primary and secondary, would not using
>> the 240 taps on both make it a 1:1 so putting 120
> -Original Message-
> From: andy pugh [mailto:bodge...@gmail.com]
> Sent: Sunday, June 14, 2015 5:06 AM
>
> What is the existing motor mount?
> I adapted my Mini-Mill to a standard 3-phase motor:
> https://picasaweb.google.com/lh/photo/Dk3wsS9o7XJ-N2kfUnESDtMT
> jNZETYmyPJy0liipFm0?feat
> -Original Message-
> From: Gregg Eshelman [mailto:g_ala...@yahoo.com]
> Sent: Sunday, June 14, 2015 4:12 AM
>
> If it has a 240 option on both primary and secondary, would not using
> the 240 taps on both make it a 1:1 so putting 120 in would
> get 120 out?
>
>
Yes the voltage rat
On 14 June 2015 at 02:38, Gene Heskett wrote:
> It does look good, but where can I get an adaptor to mount that 56C frame
> on the GO704? Or is that my first project, making one? ;-)
What is the existing motor mount?
I adapted my Mini-Mill to a standard 3-phase motor:
https://picasaweb.google.c
On 6/13/2015 8:53 AM, Jon Elson wrote:
>
> There are, however, "step down" transformers. These usually have split
> primary and secondary windings, so you can configure them for 240 or 480
> V on the primary, and 240 or 120 on the secondary. If you can tolerate
> running it at half voltage, set p
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