[Boatanchors] Relay question - again

[Garey Barrell]

Gene -

The relay used in the HA-1 is a "sensitive plate relay", and is current 
operated.  The original 9TO keyer, which was the prototype of the HA-1 
specifies the relay as a "4k plate relay".   This type of relay 
typically operates with 2-5 mA of current through the coil.   In the 
HA-1 it's connected to a +150V supply and keyed by a saturated 12AU7 
triode to ground.

If you look at Figure 5 in the HA-1 manual, you'll see that the contacts 
are rated at an amp or two with appropriate contact protection from 
inductive loads, and values recommended for R/C "snubber" components.

Mercury wetted relays are very quiet in operation, and very fast with no 
contact "bounce".  All good things for a "keying" relay!

73, Garey - K4OAH
Atlanta

Drake B & C-Line Service CDs
<http://www.k4oah.com>



WØQFC wrote:
> I am still searching for info on a CP CLARE # HG 3056 mercury relay.
> I understand that the Hallicrafters HA1 "TO KEYER" used this relay 
> (Hallicrafters part # 021-000528). The HA1 schematic/parts list does not 
> reveal the coil voltage -  it is used in the pate circuit of V4.
> I would like to know the original specs on this relay: coil voltage and 
> contact current.
> Several fellows have responded to previous post with info, but 
> unfortunately, the info was not correct.
> Lacking the original specs, can anyone tell me on what voltage the relay 
> would operate - the DC resistance of the coil is 598 ohms.
> I have spent hours searching the net using various search engines and have 
> come up empty.
> TIA
>
> 73
> Gene, WØQFC
> Spring Hill, Florida
> WEB SITE:
> http://www.w0qfc.com
>