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Re: 180 BPS synch? (fwd)

---------- Forwarded message ----------
Date: Tue, 17 Jul 2007 18:04:44 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: 180 BPS synch? (fwd)

120V 1-phase does not come in anything larger than 1-HP. No one had this 
in the past except the Altivar 11 and a drive made by TBWoods (which 
sucked!). ABB and Seimans promised this for several years, but I finally 
gave up on them. I expect the market was estimated to not be worth it 
(it's been over a year since I dealt with all the drive companies, so 
maybe one of the other brands now how this). Anyway, I run a 2HP motor, 
thus the 240V input (the 240V input was standard for 2 to 7 HP).

The only problems I've encountered with the drive is quick slowing or 
speeding up. If you slow too quickly, an overvoltage error can occur due 
to generation, but this is manageable. The Altivar 28 had several of 
these occurrences, but with the Altivar 31, it seems to perform well. 
When an OV error occurs, the drive will freewheel to a stop (at least 
you should set it up for this and not brake it with DC Injection 
braking). I use the error output signal from the drive to shut down the 
coil just in case of this. This is one of the reasons I let a computer 
control the safety functions (it's much faster than I am at opening up 
the contactor). Really not a big deal, but as long as I had the toys, I 
figured I might as well use them.

Take care,

Tesla list wrote:

>---------- Forwarded message ----------
>Date: Tue, 17 Jul 2007 20:07:42 +0000
>From: nancylavoie@xxxxxxxxxxx
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: Re: 180 BPS synch? (fwd)
>That was an issue brought up by the Allen Bradley salesmen.Apparently
>VFD's are VERY prone to problems caused by transient voltages.Lots of talk
>of shielding and grounding .By the way,is there any particular reason why
>you would choose to use the 3phase 240 deal over the single phase 120 in
>this application? Might prove to be alot cheaper. Just wondering.  Wyatt