[GreenKeys] Teletype Corp. machine with a tube (was acrylic case)

[Duncan Brown]

Robert,

The TT-30/Model 31 the motor & DC generator is a single unit. I didn't 
open it up to see how it is wired, but the manual (Teletype Corp. Bul 
1140, Oct 1947) refers to it as a "dynamotor."

have fun,

Duncan
K2OEQ

On 2/2/2019 12:48, Robert Downs wrote:
>
> Duncan.
>
> No argument that it is the only machine to have a generator built in 
> but technically, it would be a Motor-Generator instead of a 
> Dynamotor.  In a dynamotor, the motor and the generator are both on 
> the same armature.  In an M-G set, they are separate units 
> mechanically coupled.
>
> Robert Downs
>
> *From:*greenkeys-bounces at mailman.qth.net 
> [mailto:greenkeys-bounces at mailman.qth.net] *On Behalf Of *Duncan Brown
> *Sent:* Saturday, February 2, 2019 09:49
> *To:* Nick; Green Keys
> *Subject:* [GreenKeys] Teletype Corp. machine with a tube (was acrylic 
> case)
>
> Nick,
>
> Teletype Corp did make a machine with an electron tube in it: the 
> Model 31 (AKA TT-30/AGA-1) that ran on 28VDC. A 35L6GT was used to 
> switch a resistor into the motor circuit of the series governed DC 
> motor for speed control. It was a KTP machine that was designed for 
> use with RTTY/RATT. They were apparently afraid the normal open 
> contacts in the speed control would produce too much RFI.  Although 
> running on 28VDC, the 35L6GT apparently had enough gain with 28 VDC on 
> the filaments and would probably last a bit longer.
>
> The first time I powered up the Museum's unit, it seemed to run OK for 
> a few seconds, but then it slowed down. I quickly killed the power and 
> checked  the unit for something binding or a bad bearing. Everything 
> seemed OK, so I powered it up and it did the same thing: slowed down 
> after a few seconds. Then it ran fine and I suddenly realized that you 
> had to wait for the tube to warm-up before the speed control took effect!
>
> There is also a 250VDC generator connected to the TTY's motor to 
> provide voltage for the loop and the FSK converter. So the TT-30, 
> besides being the only TTY with a tube, is also the only  TTY with a 
> dynamotor!
>
> Have fun,
>
> Duncan
> K2OEQ
>
> On 2/1/2019 20:29, Nick wrote:
>
>     And the vacuum tube you can see on the lower right side above the
>     switch inside the case is just a little steampunk add-on. The tub
>     actually works, it is a Dekatron counting tub, spinning around to
>     an adjustable speed. At our event last weekend, I pulled
>     somebody's leg and said: "this is a super rare tube driven
>     teletype machine, probably the only one on the planet" - but the
>     guy figured it out pretty quickly and we both laughed.
>
>     Enjoy the pics - any improvement ideas are always welcome.
>
>     73
>
>     Nick  -  N0NCQ
>

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