[GreenKeys] Starting Up an Old Debate

[Bob Camp]

Hi

If you have a working 60 ma machine and drop the current to 40 ma then 
I would assume that odd things would happen. If you have a working 20 
ma machine and then hook the magnets in parallel (making no other 
adjustments) then it should work fine on 40 ma.

Going from 60 ma to 20 ma always seemed to involve some adjustment to 
the machine. On a 15 printer the main thing you have to do is to change 
the tension on the selector magnet armature. It's been a while since I 
fiddled with a 19 punch so I'm not sure what you have to do there when 
you go from 60 ma to 20 ma. I always ran my 19's on 60 ma and didn't 
think much about it.

	Take Care!

		Bob Camp
		KB8TQ


On May 30, 2004, at 10:06 PM, Wayne LeTourneau wrote:

>
>   ----- Original Message -----
>   From: "Bob Camp" <ham at cq.nu>
>   To: "greenkeys maillist" <greenkeys at mailman.qth.net>
>   Sent: Sunday, May 30, 2004 8:33 PM
>   Subject: [GreenKeys] Starting Up an Old Debate
>
>
>> Hi,
>>
>> There simply has not been enough controversy in the world recently. In
>> keeping with modern thought that anybody who is more than 10 seconds
>> away from a heart attack isn't really living I feel that we here on
>> Greenkeys need to add to the level of stress in the world. Nothing is
>> better at doing this than stirring up old questions to which there are
>> no answers. These questions are the most useful if there are strong
>> attachments to the answers. They are rarely useful in raising stress
>> levels if nobody cares about the answers. Since Teletype loop current
>> levels are pretty much at the top of people's list when it comes to
>> important issues here goes ....
>>
>> Ok if I put the selector magnets in series I run them off of a 20 ma
>> loop.
>>
>> If I put the *same* magnets on the *same* machine in parallel I run
>> them off of a 60 ma loop.
>>
>> In one case I have 20 ma through each magnet in the other case I have
>> 30 ma through each magnet.
>>
>> Obviously something's wrong here. It should be 20 ma and 40 ma - or -
>> 30 ma and 60 ma ...  not 20 ma and 60 ma.
>>
>> The phone company had good reasons for using 20 and 60 ma and it 
>> worked
>> just fine. You fiddled the machine a little and it would tolerate
>> running off of either loop current (20 ma per magnet or 30 ma per
>> magnet.). A little messing with the spring tension on the selector
>> armature was usually about all it took.
>>
>> The question is: since we don't work for the phone company .... why 
>> not
>> use a 40 ma parallel loop? It should work just fine. It would use a
>> lower power power supply than a 60 ma loop. Think of all the energy we
>> could save :) ...  It would be something new to try with 70 year old
>> machines ....
>>
>> Take Care!
>>
>> Bob Camp
>> KB8TQ
>
>   Hi
>   This may work with some machines, but if you are using a model 19 
> and the
> current drops just a little below 60ma the tape punch blocks do not 
> work
> properly. You start punching and printing errors. Might hit an "R" key 
> and
> punch or print an "N" or somthing else.
>   Wayne  wb0cte
>>
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>