[MAMS] relay driver

[Danny Pease]

I see 225 mA of steady current when 13.6 VDC is applied. The case does warm
up noticeably after 20 seconds or more and is almost hot after 90 seconds. I
don't think I will want to leave the DC applied all the time.

Danny NG9R


-----Original Message-----
From: mams-bounces at mailman.qth.net [mailto:mams-bounces at mailman.qth.net] On
Behalf Of Dr. Gerald N. Johnson
Sent: Friday, September 07, 2012 1:30 PM
To: mams at mailman.qth.net
Subject: Re: [MAMS] relay driver

There are at least a couple two coil latching relay schemes. One is just two
coils tha you only need to apply a pulse to for a short period and the relay
mechanically or magnetically latches. I don't see a restriction in the
catalog that requires power be removed from the coil right away except that
the current of some latching versions at 12 volts is 230 ma and the same
relay not latching (fail safe) is 195 ma, so there's more heat in the relay
with continuous coil power. Then, of course, it takes applying power to the
other coil to change the relay position. Coils often have one wire in common
and are polarity sensitive so that prevents some simple drive circuits based
on conventional relay drive.

Some Dow-Key also have a self cutoff circuit, so keep the power consumption
low by taking care of interrupting the coil current on their own to make the
drive circuit simpler.

I have portions of a recent Dow-Key relay catalog on my other computer but
need a model number to know what you have and how to drive it.

73, Jerry, K0CQ

On 9/7/2012 12:47 PM, Danny Pease wrote:
> I picked up a two coil 12 volt latching DowKey SMA relay and am 
> looking for simple suggestions for using it or I would be glad to 
> trade it for a non latching SMA relay, 12 or 24 volt.
>
> Danny NG9R
>
>
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