Help required 240 1 phase to 415 volts 3 phase
Mr Fidget
Peter Wilson wrote:
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This is what Noel would like to say for those of you using a real O/S :)
>Help wanted
>Electrical Phase Convertors - converting 240 volt single phase to 415 >volt 3 phase using a static converter.
>We have made a unit using an autotransformer to take the voltage from >240 volt 1 phase to 415 volt 1 phase then generate the third phase with >capacitors. We use a start capacitor to start along with run capacitors >then disconnect the start when up to speed then run on the run >capacitors alone.
>Question: has anyone made a similar system. If so have they made a >system that started a second motor after starting the first motor. If >so did you use the start circuit to start the second motor or did it >start on the run only.
>We would like to install a system in a milking dairy which has 3 motors >starting & stopping at various intervals. We do not want to install an >idler motor if possible.
>We would appreciate any info anyone has on this or any systems that has >been used successfully.
>
>Noel Wilson
Regards
Chris Wilson
***No we are not related....unless someone jumped the fence a few
generations ago ;)
Brad Sandberg
I'm kind of curious as to why you are against using a rotary phase
converter (i.e. a three phase motor using capacitance to generate a
third leg) this would have several distinct advantages.
Now, basically, what you are doing is using each three phase motor as
a single phase motor. and using start capacitors on the third phase
to start them. Once one motor is started you are effictively using IT
as a rotary phase converter, any motors started while connected to the
same circuit is starting on an unbalanced three phase system.
If you use a single rotating motor (a "dummy motor" ) as your
converter it would only have to be started once (starting it is the
hardest part, but you have already mastered that by switching a start
circuit in and out manually. After your main converter is running you
could use standard three phase controls to start and stop your other
motors without the need to manually start them. You wouldn't need a
transformer at all if you use a dual voltage three phase motor for
your converter. the voltage will be a little higher than 415, but
your motors should be able to handle at least a 10% variance in input
voltage, close enough considering you can expect to lose about 1/3 of
your horsepower anyway.
Oh, another advantage of a rotary converter - as you put more motors
on the line capacity for running more horsepower on your motors
increases (up to a point of course) as long as you switch them on one
at a time you can expect to be able to run, for instance, four 5 HP
motors with only a 7-1/2 HP converter.
Yo! Anybody Out There?
dmc
Use a step up transformer and a variable speed control to achieve 3 phase
output that will allow you to make a volts per hertz pattern of your
chosing along as it is something less then input voltage applied. Need
price? Email me d...@ix.netcom.com. Units are in stock!!!
Brad Sandberg <moto...@netins.net> wrote in article
<339cd554...@news.netins.net>...