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THE AM BULLETIN BOARD => Technical Forum => Topic started by: k1jos on December 17, 2013, 11:29:13 PM



Title: Determining if DowKey Coil is AC or DC ?
Post by: k1jos on December 17, 2013, 11:29:13 PM
Hi,

I have a heavy duty Dowkey that looks in great shape but the coil markings have worn off.  Whats the best method to determine if the coil is DC or AC besides trial and error?

thanks
jerry


Title: Re: Determining if DowKey Coil is AC or DC ?
Post by: n2bc on December 18, 2013, 03:56:28 AM
Not sure what "heavy Duty" means... I have a SPDT 110VAC dow key, coil measures 3090 Ohms.  Don't have a DC coil for comparison.


Title: Re: Determining if DowKey Coil is AC or DC ?
Post by: WA2ONK on December 18, 2013, 07:00:28 AM
I have three 110vac DowKey relays here. I measured between 440-320 ohms for those. I have two 12vdc DowKeys, they measure 44 ohms and 65 ohms. All are SPDT.

Chuck...wa2onk


Title: Re: Determining if DowKey Coil is AC or DC ?
Post by: N2DTS on December 18, 2013, 02:28:49 PM
I would variac ac voltage to it and see what it does.
You can tell the voltage and if its ac or dc.


Title: Re: Determining if DowKey Coil is AC or DC ? **OOPS**
Post by: n2bc on December 18, 2013, 04:24:44 PM
My earlier post station 3090 ohms.  Excuse fuzzy eyeballs, should read 310 ohms,

My thanks to Chuck


Title: Re: Determining if DowKey Coil is AC or DC ?
Post by: flintstone mop on December 19, 2013, 07:35:03 PM
I would variac ac voltage to it and see what it does.
You can tell the voltage and if its ac or dc.
Really good idea. If the coil is designed for DC and you apply AC it will buzz.
There was a trick that makes a DC coil operate with AC..something about a shader core on top of the coil.
It seems that the transfer relays used 'back in the day' were AC operated.
Fred
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