Power Factor Correction for a small 60W AC Induction motor

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  • #51
Tom.G
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Post 49, above:
Lsecondary = N2secondary X Konstant
knowing Nsecondary = Nprimary X 55/220 ?
Looks like a Square got dropped. I get 0.5H.

LPRI = 8H
L is proportional to turns2
220/55 = 4 (turns ratio)
42 = 16
8H/16 = 0.5H
 
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  • #52
jim hardy
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Tom's right of course, my mistake, haste makes waste...... Thanks Tom !!!!


Look at that inductance equation.
A gap in the magnetic path adds a section of length with term μ of only 1 instead of the few thousand that's typical of transformer steel.
So it knocks inductance down smartly.
If you can find a transformer with say a winding good for 48volts at 3 amps
and add to it an air gap
that should do.
Sometimes transformers that look like this
upload_2016-5-6_6-29-0.png


have underneath that sheet metal wrapper a core that looks like this,
transformer-theory-oct-1960-popular-electronics-11.jpg

http://www.rfcafe.com/references/po...nsformer-october-1960-popular-electronics.htm
(an interesting little article there, by the way)

you can see how easy it would be to place a thin spacer between the E and I shaped pieces and measure resulting inductance change..

You could wind your own coil, too.

old jim
 
  • #53
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Dear old Jim,

Your references, and explanations are vociferous!

Let me ask you at the moment about a switch, driven by PIC, that connects/disconnects caps according to code.

Popular one, is about Open-Relay Switch, but it is cored on Relay, that in turn have mechanical moving part.

I want to get rid of motion in switching, and referring to a solid-state device. the ULN2003 is a solid-state device, but its problem is that it doesn't connect load at full cycle.

What I want is a solid device, functions just like an open-relay without moving parts.

Any suggestions?

Following is a schematic for open-relay switch:

Open Relay Switch.gif
 
  • #55
jim hardy
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Your references, and explanations are vociferous!
Webster
Simple Definition of vociferous
: expressing feelings or opinions in a very loud or forceful way : expressed in a very loud or forceful way
I've been called worse.....:smile:

when you read that Crydom link
look at the 'zero crossing' variety of SSR's. They'll be gentle on your caps.
 
  • #56
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Dear old Jim,

It was a metaphor or equivalent.

Please tell me how to add images via private messaging. <Beside adding image URL, and if having image on the hard disk>

Thank you
 

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