[GreenKeys] Flowtrol Rectifier

[chris johnson]

Whats odd is from the outside I dont see any tubes Ill send a pic once I open it up its a cool looking thing...
________________________________
From: Jim Haynes <jhhaynes at earthlink.net>
Sent: Thursday, February 9, 2023 3:07 PM
To: chris johnson <archangel_cpj at hotmail.com>
Cc: greenkeys at mailman.qth.net <greenkeys at mailman.qth.net>
Subject: Re: [GreenKeys] Flowtrol Rectifier

On Tue, 7 Feb 2023, chris johnson wrote:

> The model 19 I got has this giant Flowtrol Rectifier on it doesnt appear to

Lorain was a company that made a lot of power supplies for the telecom
industry, think it was later named Power Equipment Co. and then was bought
by North Electric.  A major supplier to Teletype.  Their specialty was
constant-voltage transformers.  A.K.A. ferroresonant transformers, but
that term is also used for something else in the power industry.
But Flotrol sounds like their product line for floating storage batteries
rather than for use in Teletype gear.

There were several kinds of rectifiers used in Model 19 sets, which needed
a lot of DC to run the punch magnets.  A constant voltage transformer
supply made by Power Equipment Co. was frequently supplied.  I've also
seen one by Western Electric that used a magnetic amplifier to regulate
the voltage - this included a couple of VR tubes as the voltage reference.
Then there was one with thyratron rectifiers for the military, because
constant voltage transformers are frequency-sensitive and military power
often comes from generator sets that are not very accurate in frequency.
(Same reason that a lot of military TTY gear uses speed governed motors
instead of sync motors)  Then I've seen a Western Union model 19 with
a power supply of their own design which was simply unregulated, so
cheaper and smaller and lighter than the usual ones Teletype supplied.

And I don't know if they used copper oxide rectifiers early on, but
later used selenium and then silicon (and perhaps briefly germanium).
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