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Re: 180 BPS synch? (fwd)

---------- Forwarded message ----------
Date: Sat, 14 Jul 2007 08:28:54 -0700 (PDT)
From: Yurtle Turtle <yurtle_t@xxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: 180 BPS synch? (fwd)

I have a VFD and 3 ph motor I got from Bart. I'm
essentially using "relay logic" in lieu of a PLC. I'm
using a "Run" contact to kill the coil if the VFD
faults. I too, like the ability to crank it up. The
coil definitly has a sweet spot, based on ability to
charge the tank caps (amps). If you go above the sweet
spot, it gets shorter, more frantic sparks. Definiely



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

> ---------- Forwarded message ----------
> Date: Fri, 13 Jul 2007 22:42:47 -0700
> From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: 180 BPS synch? (fwd)
> Hi Scott,
> My VFD is pretty darn standard. I insert 220 VAC (or
> 240, whatever) 
> single phase. The output of the VFD is 3-phase which
> is cabled directly 
> to a 2HP 3-phase motor. The output is 230 VAC
> 3-phase. T1, T2, T3, and 
> Ground (4-wires).  The VFD does happen to be
> controlled by a PLC, but 
> this is not necessary. The only reason I use a PLC
> is to incorporate 
> safety's into my control. The VFD outputs an error
> signal if something 
> freaks out. The PLC detects the error and shuts down
> the coil. There are 
> a few other misc. features which includes a low
> voltage dead man switch, 
> cabinet safety's, alarm signals, etc... That's all
> PLC crap.
> The VFD itself is wired up to accept a 0 to 10mA
> signal that controls 
> the speed from 0 to 500 Hz. I have a 10k ohm pot
> mounted to the control 
> panel which serves to adjust the speed control. In
> the past, I have also 
> ran the VFD with a binary input for 16 preset
> speeds. The speeds are 
> simply entered into the VFD with the VFD pushbutton
> controls ( set the 
> Hz of each speed). The rotary switch then selects a
> binary input and 
> tells the VFD to run at SP2, SP5, SP10, (whatever).
> That was fine, but I 
> find the pot variable adjustment the best for coils.
> I use an Altivar 31 VFD by Telemecanique.
> Telemecanique was once known 
> as "not the greatest of VFDs". That has changed in
> the past 4 years. The 
> company actually was revamped. Nowadays, their
> drives are probably the 
> easiest to use and are now very reliable. Especially
> the Altivar 31 
> series (versus the old Altivar 28 which was pure
> Telemecanique of old).
> 3-phase motors are the most efficient of motors and
> VFD's allow us to 
> use them. They are capable of forward, reverse, and
> variable speeds. 
> Most elevators use them to get you to floor 99 and
> down to the basement. 
> Isn't it interesting how smooth elevators are and
> when they reach a 
> particular floor, you can "feel" them slow to a
> perfect stop. That is 
> "all VFD" control. But elevators are simply 1 in
> 1000 applications. When 
> it comes to motor control, 3-phase is industry
> standard and VFD's are 
> their industry standard control module. In motor
> control, Allen Bradley 
> is still top of line for VFD's. But the others now
> are right there with 
> them in capability. The main difference is that
> industries are tied into 
> a particular breed by the code they write. It would
> be an expensive task 
> to change over to something else. So, they stick
> with what they are 
> familiar with. I do the same. I understand that
> situation completely.
> Take care,
> Bart
> Tesla list wrote:

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