Mechanical Relays

[Cursitor Doom]

Gentlemen,

I have acquired, over the years, a great many mechanical relays (I think
it's the same word in both US and British English). They are bulky, heavy
and I don't find myself using them much any more, preferring to do
switching via MOSFETs instead. The question is: is there any point in
keeping the old relays in this day and age? If everything they can do can
be done by MOSFETs then there seems very little point. Any suggestions?

I was thinking I might as well unwind their cores onto spools (I have an
engine lathe) keep the wire thusly obtained and throw the rest away?



--
This message may be freely reproduced without limit or charge only via
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protocols constitutes acceptance of this condition.

 

[Michael Kellett]

On 29/10/2019 08:39, Cursitor Doom wrote:

Gentlemen,

I have acquired, over the years, a great many mechanical relays (I think
it's the same word in both US and British English). They are bulky, heavy
and I don't find myself using them much any more, preferring to do
switching via MOSFETs instead. The question is: is there any point in
keeping the old relays in this day and age? If everything they can do can
be done by MOSFETs then there seems very little point. Any suggestions?

I was thinking I might as well unwind their cores onto spools (I have an
engine lathe) keep the wire thusly obtained and throw the rest away?

Keep them, the thing I most regret is getting rid of my first car, worth
more than the house now, or the Truvox reel to reel tape recorder -
worth damn all even now but still a thing of wonder and beauty !

Imagine if I'd kept all the OC44 and other OCxx transistors I had when I
was 12 - going for ÂŁ10 a pop on Ebay now !

Show us some pictures (of your relays) - and if nice, I'll show you a
picture of the inside of my ancient Sullivan inductance bridge (and see
if anyone can identify the weird variable transformer things).

MK

 

[Winfield Hill]

Cursitor Doom wrote...

Gentlemen,

I have acquired .. a great many mechanical relays ...

Haha, mechanical relays vs MOSFETs, IGBTs. Some PROs:

* much lower capacitance (sub pF)
* handle higher current (contactors)
* lower voltage drop (sub uV, zero)
* handle higher voltages (30kV, yep)
* lower power (latching types)

Here's an example of a 100A 1.2kV switching application
that benefited from a relay taking over most of the time.
From the new x-Chapters book: Fast magnetic-field shutoff.

https://www.dropbox.com/s/5hj9idbou3jct8v/3x.21_fast-mag-field-shutoff.pdf?dl=1


--
Thanks,
- Win

 

[Tom Gardner]

On 29/10/19 08:39, Cursitor Doom wrote:

Gentlemen,

I have acquired, over the years, a great many mechanical relays (I think
it's the same word in both US and British English). They are bulky, heavy
and I don't find myself using them much any more, preferring to do
switching via MOSFETs instead. The question is: is there any point in
keeping the old relays in this day and age? If everything they can do can
be done by MOSFETs then there seems very little point. Any suggestions?

I was thinking I might as well unwind their cores onto spools (I have an
engine lathe) keep the wire thusly obtained and throw the rest away?

If the coil voltage is OK, give them and a transformer to pre-teen
kids to play with.

The young kids will enjoy seeing the contacts move, and might learn
to respect electricity if they get zapped by back EMF when breaking
the current to the coil.

I taught my daughter to be careful around electricity by getting
her to touch an electric fence with the back of her hand. I touched
it first, and educated her as to why the back of the hand was safer
than inside her grip.

 

[Phil Allison]

Cursitor Doom wrote:

--------------------

Gentlemen,

** Where are they ?

I have acquired, over the years, a great many mechanical relays (I think
it's the same word in both US and British English). They are bulky, heavy
and I don't find myself using them much any more, preferring to do
switching via MOSFETs instead. The question is: is there any point in
keeping the old relays in this day and age? If everything they can do can
be done by MOSFETs then there seems very little point. Any suggestions?

** Switching the AC supply, low cost changeover & multi-pole switching, simple small signal switching without loss.

They do pretty much everything better stupid mosfets except switch at high speeds.



...... Phil

 

[Andreas Karrer]

* Michael Kellett <mk@mkesc.co.uk>:

On 29/10/2019 08:39, Cursitor Doom wrote:
Gentlemen,

I have acquired, over the years, a great many mechanical relays (I think
it's the same word in both US and British English). They are bulky, heavy
and I don't find myself using them much any more, preferring to do
switching via MOSFETs instead. The question is: is there any point in
keeping the old relays in this day and age? If everything they can do can
be done by MOSFETs then there seems very little point. Any suggestions?

I was thinking I might as well unwind their cores onto spools (I have an
engine lathe) keep the wire thusly obtained and throw the rest away?



Keep them, the thing I most regret is getting rid of my first car, worth
more than the house now, or the Truvox reel to reel tape recorder -
worth damn all even now but still a thing of wonder and beauty !

Imagine if I'd kept all the OC44 and other OCxx transistors I had when I
was 12 - going for Ł10 a pop on Ebay now !

The retail price of said OC44 in 1965 was? Probably Ł1? Then Ł10
would be less than the UK inflation rate (1920% according to
http://www.in2013dollars.com/uk/inflation/1965).

S&P 500 gained 16148% nominal in that period (in USD).

- Andi

 

[Phil Allison]

Michael Kellett wrote:

----------------------

Imagine if I'd kept all the OC44 and other OCxx transistors I had when I
was 12 - going for ÂŁ10 a pop on Ebay now !

** I remember seeing OC44s back in the 60s, cos it was safe for kids to play with battery powered stuff.

If you scraped the black paint off one, they made dandy photo-transistors.



...... Phil

 

[Michael Kellett]

On 29/10/2019 11:21, Phil Allison wrote:

Michael Kellett wrote:

----------------------


Imagine if I'd kept all the OC44 and other OCxx transistors I had when I
was 12 - going for ÂŁ10 a pop on Ebay now !



** I remember seeing OC44s back in the 60s, cos it was safe for kids to play with battery powered stuff.

If you scraped the black paint off one, they made dandy photo-transistors.



..... Phil

At first, some of the later ones had opaque gunge inside - I can
remember my Dad explaining this to me.
The gunge may not have been malicious - maybe bright light could get
through defects in the black paint.

MK

 

[John Robertson]

On 2019/10/29 2:18 a.m., Winfield Hill wrote:

Cursitor Doom wrote...

Gentlemen,

I have acquired .. a great many mechanical relays ...

Haha, mechanical relays vs MOSFETs, IGBTs. Some PROs:

* much lower capacitance (sub pF)
* handle higher current (contactors)
* lower voltage drop (sub uV, zero)
* handle higher voltages (30kV, yep)
* lower power (latching types)

Here's an example of a 100A 1.2kV switching application
that benefited from a relay taking over most of the time.
From the new x-Chapters book: Fast magnetic-field shutoff.

https://www.dropbox.com/s/5hj9idbou3jct8v/3x.21_fast-mag-field-shutoff.pdf?dl=1

I didn't realize you guys were into relays. And here I have shelves of
them - NOS - that I was going to put up for sale when I got around to
it. Mercury wetted, regular, timer, etc...

https://flippers.com/images/Main_Electronics/Main_Electronics_Relays.jpg

Picked these up from a radio/TV parts retail/wholesaler (Main
Electronics in Vancouver, BC) where the owners died (father and son,
real nice guys) and the family sold off the inventory. Parts going back
to the 60s...

John :-#)#

--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."

 

[Cursitor Doom]

On Tue, 29 Oct 2019 09:19:12 +0000, Michael Kellett wrote:

Show us some pictures (of your relays) - and if nice, I'll show you a
picture of the inside of my ancient Sullivan inductance bridge (and see
if anyone can identify the weird variable transformer things).

I'd like to, but the really interesting ones are all currently out of
reach on a hill of vintage components surrounded by a moat of small
fragile components behind a wall of large and heavy test equipment.
Sigh. It's such a mess here.




--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
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[Cursitor Doom]

On Tue, 29 Oct 2019 02:18:41 -0700, Winfield Hill wrote:

* much lower capacitance (sub pF)
* handle higher current (contactors)
* lower voltage drop (sub uV, zero)
* handle higher voltages (30kV, yep)
* lower power (latching types)

Here's an example of a 100A 1.2kV switching application that benefited
from a relay taking over most of the time. From the new x-Chapters
book: Fast magnetic-field shutoff.

https://www.dropbox.com/s/5hj9idbou3jct8v/3x.21_fast-mag-field-
shutoff.pdf?dl=1

Noted, Win! And before I forget, let me thank you sincerely for your
input iro the spectrum amplifier X-amplifier. Your analysis of the
schematic made it *way* easier for me to work out what had gone wrong
with it and it's now up and running again with a *full* horizontal trace,
thanks entirely to your good self. Exemplary!




--
This message may be freely reproduced without limit or charge only via
the Usenet protocol. Reproduction in whole or part through other
protocols, whether for profit or not, is conditional upon a charge of
GBP10.00 per reproduction. Publication in this manner via non-Usenet
protocols constitutes acceptance of this condition.

 

[John Larkin]

On 29 Oct 2019 02:18:41 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

Cursitor Doom wrote...

Gentlemen,

I have acquired .. a great many mechanical relays ...

Haha, mechanical relays vs MOSFETs, IGBTs. Some PROs:

* much lower capacitance (sub pF)
* handle higher current (contactors)
* lower voltage drop (sub uV, zero)
* handle higher voltages (30kV, yep)
* lower power (latching types)

Here's an example of a 100A 1.2kV switching application
that benefited from a relay taking over most of the time.
From the new x-Chapters book: Fast magnetic-field shutoff.

https://www.dropbox.com/s/5hj9idbou3jct8v/3x.21_fast-mag-field-shutoff.pdf?dl=1

This little Fujitsu DPDT is fabulous.

https://www.dropbox.com/s/x0qd4als1s7tco3/Fujitsu_FTR.zip?dl=0

That's about 3 GHz equivalent usable switching.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[Don Kuenz, KB7RPU]

Andreas Karrer <ak-9a@gmx.ch> wrote:

* Michael Kellett <mk@mkesc.co.uk>:
On 29/10/2019 08:39, Cursitor Doom wrote:
Gentlemen,

I have acquired, over the years, a great many mechanical relays (I think
it's the same word in both US and British English). They are bulky, heavy
and I don't find myself using them much any more, preferring to do
switching via MOSFETs instead. The question is: is there any point in
keeping the old relays in this day and age? If everything they can do can
be done by MOSFETs then there seems very little point. Any suggestions?

I was thinking I might as well unwind their cores onto spools (I have an
engine lathe) keep the wire thusly obtained and throw the rest away?



Keep them, the thing I most regret is getting rid of my first car, worth
more than the house now, or the Truvox reel to reel tape recorder -
worth damn all even now but still a thing of wonder and beauty !

Imagine if I'd kept all the OC44 and other OCxx transistors I had when I
was 12 - going for ÂŁ10 a pop on Ebay now !

The retail price of said OC44 in 1965 was? Probably ÂŁ1? Then ÂŁ10
would be less than the UK inflation rate (1920% according to
http://www.in2013dollars.com/uk/inflation/1965).

S&P 500 gained 16148% nominal in that period (in USD).

A Ferrari that originally sold for $4,000 in 1963 sold for $38 million
in 2014, for a gain of 950000%. [1] (Inflation, dollar devaluation,
creating ever more dollars, is a financial mechanism that gives
politicians a blank check to squander as they see fit.)

Most of the mechanical relays in my small collection came from broken
battery backups. The current revision of Tripp Lite's SMART1500LCD
contains four KLT1C20DC24 relays and two 894H2AH1 relays. Tripp Lite
certainly knows about the merits of power MOSFETs, as thirteen P60NF06
are also used.
Heath/Zenith's HZ-5411-WH motion activated security light system
also uses a relay, something along the lines of a RUT-SS-124DM. But it's
special order now; it's apparently been dropped from retail shelves to
make room for LED security lights, which seem better suited to solid
state solutions.
The K180V3 Rolling Code kit [2] contains four mechanical relays. DIY
Kits being being DIY Kits, you will probably always find one or more DIY
Kits stuffed with one or more mechanical relays.

Note.

[1] https://www.latimes.com/business/autos/la-fi-hy-70-million-dollar-ferrari-sale-20140814-story.html
[2] http://kitsrus.com/pdf/k180v3.pdf


Thank you, 73,

--
Don Kuenz, KB7RPU
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[Joseph Gwinn]

On Oct 29, 2019, Winfield Hill wrote
(in article <qp905h031kp@drn.newsguy.com&gt:

Cursitor Doom wrote...

Gentlemen,

I have acquired .. a great many mechanical relays ...

Haha, mechanical relays vs MOSFETs, IGBTs. Some PROs:

* much lower capacitance (sub pF)
* handle higher current (contactors)
* lower voltage drop (sub uV, zero)
* handle higher voltages (30kV, yep)
* lower power (latching types)

Here's an example of a 100A 1.2kV switching application
that benefited from a relay taking over most of the time.
From the new x-Chapters book: Fast magnetic-field shutoff.

https://www.dropbox.com/s/5hj9idbou3jct8v/3x.21_fast-mag-field-shutoff.pdf?dl=
1

Win,

Just curious - does AoE cover mercury-pool ignitrons?

..<https://en.wikipedia.org/wiki/Ignitron>

Think of it as a *very* large and rugged thyratron, suitable for an aluminum
pot line, for instance.

I suppose solid-state thyratrons could be used to drive the igniter (gate)
terminal. Maybe.

Joe Gwinn

 

[Tauno Voipio]

On 29.10.19 17:53, Michael Kellett wrote:

On 29/10/2019 11:21, Phil Allison wrote:
Michael Kellett wrote:

----------------------


Imagine if I'd kept all the OC44 and other OCxx transistors I had when I
was 12 - going for ÂŁ10 a pop on Ebay now !



** I remember seeing OC44s back in the 60s, cos it was safe for kids
to play with battery powered stuff.

If you scraped the black paint off one, they made dandy
photo-transistors.



.....  Phil


At first, some of the later ones had opaque gunge inside - I can
remember my Dad explaining this to me.
The gunge may not have been malicious - maybe bright light could get
through defects in the black paint.

MK

It still worked as photo-transistor despite of the gunk.

I made a telephone using OC71's for receiving and flashlight
bulbs for sending. The antennas were discarded car headlight
reflectors.

And, yes, an incadescent bulb could be modulated with speech. In
1960 there were no LEDs yet.

--

-TV

 

[Chris Jones]

On 29/10/2019 19:39, Cursitor Doom wrote:

Gentlemen,

I have acquired, over the years, a great many mechanical relays (I think
it's the same word in both US and British English). They are bulky, heavy
and I don't find myself using them much any more, preferring to do
switching via MOSFETs instead. The question is: is there any point in
keeping the old relays in this day and age? If everything they can do can
be done by MOSFETs then there seems very little point. Any suggestions?
A relay is more likely to survive static discharges, nearby lightning etc.

I was thinking I might as well unwind their cores onto spools (I have an
engine lathe) keep the wire thusly obtained and throw the rest away?

Sometimes I do use relays as a source of winding wire - it is hard to
buy small quantities of very fine gauges any other way. If you do this
then I suggest that you store it in the original relay. This way it is
more compact (much packaging is required to store winding wire without
scratching its insulation), avoids unnecessary damage to the wire due to
re-winding onto a spool, avoids investing your time in the work of
re-winding it that may never pay off if you happen not to require the
wire, and allows you to use the relay as a relay if that turns out to be
more useful to you sooner.

 

[Phil Allison]

Tauno Voipio wrote:

------------------

** I remember seeing OC44s back in the 60s, cos it was safe for kids
to play with battery powered stuff.

If you scraped the black paint off one, they made dandy
photo-transistors.



.....  Phil


At first, some of the later ones had opaque gunge inside - I can
remember my Dad explaining this to me.
The gunge may not have been malicious - maybe bright light could get
through defects in the black paint.



It still worked as photo-transistor despite of the gunk.

I made a telephone using OC71's for receiving and flashlight
bulbs for sending. The antennas were discarded car headlight
reflectors.

And, yes, an incadescent bulb could be modulated with speech. In
1960 there were no LEDs yet.

** I have read the neon lamps were use to expose film for audio tracks on early talkies. Avoiding the need for synchronised vinyl discs.

Think vacuum photo tubes were use for pickup.

That is, until PVs cam along.


..... Phil

 

[Phil Allison]

Michael Kellett wrote:

------------------------

** I remember seeing OC44s back in the 60s, cos it was safe for kids
to play with battery powered stuff.

If you scraped the black paint off one, they made dandy photo-transistors.



At first, some of the later ones had opaque gunge inside - I can
remember my Dad explaining this to me.
The gunge may not have been malicious - maybe bright light could get
through defects in the black paint.

** The "gunge" was silicone grease.

Harmless, thermally conductive and obviated the need for vacuums.

Lotsa Germanium devices had the stuff packed inside.



...... Phil

 

On Tuesday, 29 October 2019 08:39:19 UTC, Cursitor Doom wrote:

Gentlemen,

I have acquired, over the years, a great many mechanical relays (I think
it's the same word in both US and British English). They are bulky, heavy
and I don't find myself using them much any more, preferring to do
switching via MOSFETs instead. The question is: is there any point in
keeping the old relays in this day and age? If everything they can do can
be done by MOSFETs then there seems very little point. Any suggestions?

I was thinking I might as well unwind their cores onto spools (I have an
engine lathe) keep the wire thusly obtained and throw the rest away?

relay coils are already on spools


NT

 

[Winfield Hill]

Joseph Gwinn wrote...

Win,

Just curious - does AoE cover mercury-pool ignitrons?

https://en.wikipedia.org/wiki/Ignitron

No. But we do discuss thyratrons, in connection with
high-voltage pulse-forming networks, in Appendix H.3


--
Thanks,
- Win