[GreenKeys] Powering an ASR 33 Teletype in the UK

[Rob Jarratt]

I have had lots of private replies, all saying the same thing: supply is for
the motor, signal is for the interface to the computer (current loop).
Thanks to everyone for all the replies.

 

A basic multimeter test was telling me that the transformer I have might be
shorted. But I have since been told about autowound transformers, which
explains my measurement. I am going to do some simple tests on the
transformer tomorrow, initially limiting the current by using an
incandescent light bulb in case there really is a short in the transformer.

 

Regards

 

Rob

 

From: greenkeys-bounces at mailman.qth.net
[mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Rob Jarratt
Sent: 08 December 2012 20:57
To: r.jarratt at computer.org; greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] Powering an ASR 33 Teletype in the UK

 

I just noticed something else which is puzzling me a bit. On the ASR 33's
plate it says:

 

Supply Input: 115V 50Hz AC 5Amp Max

Signal Input: 120V.D.C MAX 0.07Amp Max

 

What is the difference between supply input and signal input? I am assuming
it needs me to provide a 115V 50Hz supply but I am not completely sure now.

 

Regards

 

Rob

 

From: greenkeys-bounces at mailman.qth.net
[mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Rob Jarratt
Sent: 08 December 2012 10:06
To: greenkeys at mailman.qth.net
Subject: [GreenKeys] Powering an ASR 33 Teletype in the UK

 

In the UK our power supply is 220/240V at 50Hz, and I believe the US is 110V
at 60Hz. I noticed the plate on the back of the ASR 33 I have it says 115V
at 50Hz, which rather puzzles me as it is a US voltage at a UK frequency.

I did get some kind of transformer that I think went with the ASR but I am
not sure I want to trust it, can anyone suggest a safe way to test it? I am
tempted however to buy something new for this. There are a number of voltage
converters on the market which convert UK to US, but they output at 60Hz. Am
I going to be able to use one of these converters for my Teletype or do I
need something different?

Regards

Rob

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