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Re: Contactor question



Original poster: "David Rieben" <drieben@xxxxxxxxxxxxxxx>

Jonathon,

You can see a few pics at:
http://hot-streamer.com/temp/Rieben/

David Rieben

----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Monday, August 15, 2005 11:56 PM
Subject: Re: Contactor question


Original poster: Kidd6488@xxxxxxx
Sounds like a heck of a controller? Do you have some details/ pics / schematics on this? Either on here, or just email to me if you dont think people will care...
Jonathon
In a message dated 8/15/05 1:53:37 AM Eastern Daylight Time, tesla@xxxxxxxxxx writes:
Hi David,
Yes, I know well what your are thinking here. But, the contactors do
not all make or break at the same time. Thus, the last in line to
open will see the "full" load for that brief moment. (Inductive loads
are nasty on contacts of any size). Likely, this particular contact
will always be the "slow one" and it will eventually weld closed if
opened and closed during a load, which is the key to it's use.
I use a 50A contactor. It is controlled by the PLC and will open if
the VFD has an error or for a few other reasons (dead man switch
open, key off, PLC glitch, etc.). This is "error" mode and is the
only time the contactor would actually open during a load. During
normal operation, I always have the contactor on before putting V and
I into the tranny. The contactor I use has had no problems so far.
IMO, 30A is a bit small for these swinging pig loads. Even 50A
ratings I would consider risky.
Take care,
Bart