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Commentator

Join Date: Nov 2007
Posts: 86

Solenoid coil got burnt

10/04/2009 10:55 AM

Hello everyone,

I was testing a solenoid coil of 220Volts AC. I connected the coil directly to mains and when i turned on supply.....smoke and sparks the coil got burnt. Some one told me that i have to put some magnetic thing in between the coil before connecting to mains specially AC coils that will limit the current drawn.

what i dont understand how does putting a piece of iron in the coils magnetic field will reduce the current drawn, does it has some thing to with back emf in the magnetic piece that will oppose the current drawn, if so the piece should induce eddy currents in its core and get red hot in not time. Please correct me if i am wrong

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Guru

Join Date: Jul 2007
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#1

Re: Solenoid coil got burnt

10/04/2009 12:04 PM

You are not wrong, only a bit extreme. The iron core will increase the inductance of the coil, thus raising the impedance and lowering the current. There will be eddy currents, but if properly done, should be quite low in heat.

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Commentator

Join Date: Nov 2008
Posts: 67
Good Answers: 1
#2

Re: Solenoid coil got burnt

10/04/2009 11:33 PM

Is this a solenoid for a 220VAC contactor? If so The winding may be for 12VDC, 24VDC, 110VAC or just about anything. and the 220VAC may be the contact specs??

You may want to use a variac and a current meter to test it. (If it is still use-able). If you smoked it--it's probably toast.

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Guru

Join Date: Jun 2009
Location: Bangalore, India
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#3

Re: Solenoid coil got burnt

10/05/2009 1:19 AM

http://www.mrfpr.com/Technical%20Flyer.pdf

http://www.ledex.com/solenoid/solenoid-basics.html

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#4

Re: Solenoid coil got burnt

10/05/2009 6:06 AM

"Inductive reactance" iron core, as opposed to "DC resistance" open air coil

"does it has some thing to with back emf in the magnetic piece that will oppose the current drawn"

No

http://en.wikipedia.org/wiki/Eddy_current (copy paste link)

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Guru

Join Date: Feb 2006
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#5

Re: Solenoid coil got burnt

10/06/2009 2:09 PM

Some one told me that i have to put some magnetic thing in between the coil before connecting ???

I hope when you experiment with power your not putting others at risk ? You would reget that.

Think of it as a welder. The closer the grounding cable is to the actual weld site the more powerful the ARC.

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#6

Re: Solenoid coil got burnt

10/28/2009 4:23 AM

If the coil rating of the solenoid is 220 V AC, it should not get burnt.

As it got burnt, either it has gone bad or the coil rating must be something lower.

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Commentator

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#7
In reply to #6

Re: Solenoid coil got burnt

10/29/2009 11:28 AM

Sir,

I got it confirmed that,a 220V AC coil gets burnt if it is powered up with out putting any ferric rod or stem at the center of the coil , we have tried this on many coils and we have tested that it draws more than normal current without inserting a metal rod in the coils field

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#8
In reply to #7

Re: Solenoid coil got burnt

10/29/2009 10:40 PM

Surprising!

I have many many 220V AC solenoid coils in my use for years... like contactors, valves etc. No where I had to place any sort of metal core for the coils. The supplier takes care of whatever is required to be done.

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Anonymous Poster
#9

Re: Solenoid coil got burnt

10/30/2009 11:30 AM

sir,

i particularly referring to Rotex make solenoid coils

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