[Amps] Relay rewinding

[Will Matney]

Sam,

The link provided earlier is correct in winding DC relays. I'll try to  
explain it in a little simpler terms (theory). A DC relay acts different  
than an AC relay in the current drawn in the coil because of different  
impedances. In other words, an AC coil has inductance and a DC coil has  
resistance. The trick to winding the DC coil is having enough wire in  
length to provide enough resistance that it wont burn out with a DC  
current applied. Also, to have enough magnamotive force to pull in the  
armature of the relay. To get this high amount of resistance, you end up  
with anywhere of a few hundred feet to maybe a thousand feet of wire to  
get enough resistance for the right DC current at the operating voltage.  
This is where the ampere turns comes in but it is different between AC and  
DC due to the difference between inductance and resistance.

Best,

Will

On Fri, 14 Jan 2005 15:47:40 +0700, Svante Nordenstrom <sm3dyu at ji-net.com>  
wrote:

> Hi all
> I have a number of brand new coax relays, brand Bernier type  
> LMT/B/1023526/2
> with N-type connectors. They are NO configured and makes when power,  
> which
> somewhere between 60 to 110V DC, is applied. The coil has a DC  
> resistance of
> 4.5 kohm with the dimensions 50 x 25 mm outer measurements of bobbin  
> (Sorry,
> I'm metric). Can anybody give a rough figure of what size wire and  
> number of
> turns to make it a 12VDC relay? I don't have any relevant books for this
> kind of calculations and I am probably  too rusty in the math anyway..
> 73's
> Sam  HS0ZDY
>
>
>
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