Re: 180 BPS synch, Hatachi L100 drive (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 20 Jul 2007 03:30:40 -0700 (PDT)
From: Yurtle Turtle <yurtle_t@xxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: 180 BPS synch, Hatachi L100 drive (fwd)

Besides better insulation, inverter rated motors do a
better job of cooling at low speeds, at least with the
larger ones. At work, most of our motors are TEFC
motors. We only buy inverter rated motor where we know
we will use a vfd. There's a bigger cost differential
with larger motors. We ran into problems with adding a
drive to several non-inverter rated motors. At low
speeds the internal fan couldn't cool them adequately.
(This is where bearing and winding RTD's come in
handy.) We had to retrofit a constant speed fan to
them. This shouldn't be a problem with rsg's low duty
cycle.

Adam

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> 
> ---------- Forwarded message ----------
> Date: Thu, 19 Jul 2007 00:16:03 -0700
> From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: 180 BPS synch, Hatachi L100 drive (fwd)
> 
> Hi Jim,
<snip> 
> Most 3-phase motors these days are inverter duty
> rated. All of Leeson's 
> 3-phase motors now have this rating and I'm sure the
> other manufacturers 
> (Baldor, Weg, etc.) are following suit. It's not
> overly critical, but 
> it's something that is now a requirement in various
> codes and customers 
> have caused a high demand for inverter duty rated
> motors (which is good 
> for the industry because it drives the cost down).
> 
> Take care,
> Bart


       
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