[AMRadio] WE 303J

[manualman]

I believe I have all the WECo relay information data sheets and/or a list
of models and specs. I saw them the last time I was pulling some data
information on WECo. transformers from my stash. I'll take a look later
this evening.

Pete, wa2cwa

On Thu, 17 Dec 2009 11:30:13 -0700 "JAMES HANLON" <knjhanlon at msn.com>
writes:
> Jack,
> 
> I don't have the info on the 303J you are after, but John, K2TQN, 
> gave you good advice.  If you can find just one coil winding with 
> your ohm meter, that's the one to work with.  You should be able to 
> find the normally closed contacts, they will measure very close to 
> zero ohms.  Monitor them while you ramp up voltage on the coil.  The 
> nominal coil operating voltage will probably be either 24 or 48 
> volts.  If you get up to 48 volts and the contacts have not opened, 
> reverse the polarity of the voltage and try again.  This relay will 
> have a bias magnet, so you have to get the coil polarity right to 
> make it operate.  The relay should operate on substantially less 
> voltage than its nominal rated value.  It's operating time should be 
> around 1 millisecond.  
> 
> Once the contacts have opened, you can use your ohm meter to find 
> the "normally open" contact which at that point will be shorted to 
> the swinger.  The swinger will be attached to one of the two pins 
> you've been monitoring, and the normally open contact will show up 
> on another pin.  
> 
> The mercury-wetted switch inside is probably a WE 226D, judging from 
> the size of the relay can.  That switch is a single-pole, double 
> throw switch that is of the "non-shorting" type.  The swinger will 
> break free (open circuit) from the normally-closed contact before it 
> makes to the normally-open contact on its operate cycle.  On its 
> release cycle, it will similarly open up from the normally open 
> contact before it makes to the normally closed contact.  The 226D 
> switch is rated for a maximum of 3 amps DC current, and it should 
> switch up to a 50 VA load.  Operated within its ratings, it should e 
> good for more than a billion switcing cycles.  It will not "bounce" 
> or "chatter" on either operate or release.  It should sustain more 
> than 1000 Vac rms across its open contacts, although it shouldn't be 
> used to switch that much voltage.  I've used a similar relay to 
> switch B+ on the order of 300 volts at around 0.05 amps for keying 
> purposes with no problem.  Insulation resistance of the
>   open contact should be above 100 megohms.  Resistance of the 
> closed contact should be below 50 milliohms.  
> 
> Once upon a time, back in the 70's, I was the supervisor of the Bell 
> Labs group that was responsible for the design of WE mercury wetted 
> relays, just in case you are wondering.
> 
> Hope this helps,
> 
> Jim, W8KGI