sci.electronics.repair@googlegroups.com

Today's topics:

* Contactor coil: 50 Hz vs. 60 Hz - 5 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/0d1a06068779ce43?hl=en
* Microwave oven diode bad? - 2 messages, 2 authors
http://groups.google.com/group/sci.electronics.repair/t/68504020f6b6237b?hl=en
* Motor start/stop switch with integrated mini contactor? - 2 messages, 2
authors
http://groups.google.com/group/sci.electronics.repair/t/13b233689d902984?hl=en
* Tek 465 - 1 messages, 1 author
http://groups.google.com/group/sci.electronics.repair/t/b9f473fde6856891?hl=en

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TOPIC: Contactor coil: 50 Hz vs. 60 Hz
http://groups.google.com/group/sci.electronics.repair/t/0d1a06068779ce43?hl=en
==============================================================================

== 1 of 5 ==
Date: Mon, Aug 29 2011 7:55 pm
From: David Lesher

DaveC <invalid@invalid.net> writes:

>I may be able to obtain a very small 2-pole 240 vac contactor I need rated
>for 50 Hz only.

>If I install it in N. America, what's the implication? Is the hold-in
>magnetism less than if it were 60 Hz? Just noisy?

It will be happy. If it were a 60Hz on 50, it would not be as happy.

--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

== 2 of 5 ==
Date: Mon, Aug 29 2011 7:58 pm
From: David Lesher

John Fields <jfields@austininstruments.com> writes:

>I have an old P&B MR5A here with a 240V 50/60Hz coil.

>The coil has a resistance of 4800 ohms, and an open inductance of 14.5
>henrys, so it has an impedance of 6616 ohms at 50 Hz, and 7270 ohms at
>60 Hz.

What's the inductance while closed?
--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

== 3 of 5 ==
Date: Mon, Aug 29 2011 10:36 pm
From: DaveC

> If instead you meant you would use it on 110v 60Hz, then dont. But you
> could use diodes to get a higher dc voltage and use that.
> NT

No, there are models for both 115 and 230 in both 50 and 60 Hz flavors. Here
in N. America these are difficult to get so I may have to settle for the 50
Hz models, ordered from Europe. Hence my query.

Thanks,
Dave

== 4 of 5 ==
Date: Mon, Aug 29 2011 10:40 pm
From: DaveC

.
> Since the OP didn't describe the environment.. it may or may not be.
> For aircraft work (yes, some is 60Hz) it would be a really good idea
> to check. If it's sitting on a subpanel with the control cabinet
> bolted to the floor rather than to an OBI punch press, not a big deal.
> Best regards,
> Spehro Pefhany

It's usually in old (60's & 70's) V-belt driven letterpress type printing
presses (think "clamshell" press). No vibration at the controls.

Thanks,
Dave

== 5 of 5 ==
Date: Mon, Aug 29 2011 10:41 pm
From: DaveC

> It will be happy. If it were a 60Hz on 50, it would not be as happy.
[David Lesher]

Interesting. Good to know. It's stuff like this I learn here that I wouldn't
otherwise know.

Cheers,
Dave

==============================================================================
TOPIC: Microwave oven diode bad?
http://groups.google.com/group/sci.electronics.repair/t/68504020f6b6237b?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Aug 29 2011 8:14 pm
From: JeffM

>Spamm Trappe wrote:
>>Since there obviously lacking, their ought to be continuing education
>>classes where illiterates can improve they're language skills.
>>
Michael A. Terrell wrote:
>Since you want to point out typos, it's 'their language skills',
>jackass.
>
Interesting that you dindn't mention the other 2
purposeful misuses among there/their/they're
Satire is wasted on some people.

== 2 of 2 ==
Date: Mon, Aug 29 2011 11:43 pm
From: "Michael A. Terrell"

JeffM wrote:
>
> >Spamm Trappe wrote:
> >>Since there obviously lacking, their ought to be continuing education
> >>classes where illiterates can improve they're language skills.
> >>
> Michael A. Terrell wrote:
> >Since you want to point out typos, it's 'their language skills',
> >jackass.
> >
> Interesting that you dindn't mention the other 2
> purposeful misuses among there/their/they're
> Satire is wasted on some people.

One was enough. I made my mistakes from not enough sleep, for
months. Some days I'm in so much pain that I just don't give a damn.
Neither does my VA doctor, who thinks that the medication for diabetic
neuropathy is a real pain killer. He informed me that I was already on
'A very high dosage of pain killers'.

--
You can't have a sense of humor, if you have no sense.

==============================================================================
TOPIC: Motor start/stop switch with integrated mini contactor?
http://groups.google.com/group/sci.electronics.repair/t/13b233689d902984?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Aug 29 2011 9:50 pm
From: "Wild_Bill"

Crossposted groups omitted

If the Start-Stop switch you're referring to uses the Start button to
mechanically close the contacts (and current latches the contacts closed),
then the Stop button opens the coil's holding-current circuit to allow the
contacts to open.. I've seen these types of switches on workshop machines
from China.
Harbor Freight, or any number of other machine importers/sellers could
probably supply a switch of this type.
The parts lists are available from at least a couple of said companies.

So, if it is this type of switch, any interruption of the coil current will
cause the contacts to open, and cause the machine motor to come to a stop
(until the Start button is used to close the contacts again).. meaning that
a commonly available normally closed (momentary open) switch with the proper
voltage/current ratings wired in series with the coil circuit will also act
as a Stop switch (E-Stop or other terminology).. unless the contacts become
stuck shut..
then the OHshit switch needs to be utilized.

This isn't the standard method commonly used in the US, for
starting/stopping a machine motor, but it is a cheaper way to produce a
motor starter.

--
Cheers,
WB
.............

"DaveC" <invalid@invalid.net> wrote in message
news:0001HW.CA7FDEFF01B3217BB01029BF@news.eternal-september.org...
> Hi,
> I just became aware of this item:
>
> <http://img-europe.electrocomponents.com/images/R3985229-01.jpg>
>
> Data sheet here:
>
> <http://www.pdfdoc.ru/data/pdf42805>
>
> It includes a 2-pole 16A contactor in that little size. Can also be
> ordered
> with the option of external connection for safety stop push-button switch.
>
> I can't find a USA distributor for these. Anybody know where to get these?
>
> The company is in Germany:
>
> <http://www.eichhoff.com/unternehmen_ueber-eichhoff_en.php>
>
> Or is there a domestic (USA) product that is similar?
>
> Thanks,
> Dave
>

== 2 of 2 ==
Date: Mon, Aug 29 2011 10:59 pm
From: DaveC

> Harbor Freight, or any number of other machine importers/sellers could
> probably supply a switch of this type.
> The parts lists are available from at least a couple of said companies.

I've searched for "No-Volt Release" (NVR) switches and have found very, very
few here in N. America. The US definition is a full contactor inside a
housing with a start/stop combo switch on the front. Not my idea of "min".

Europe uses these much more.

HF doesn't list anything like this.

If you know of any manufacturers I'd be glad to know of them.

> So, if it is this type of switch, any interruption of the coil current will
> cause the contacts to open, and cause the machine motor to come to a stop
> (until the Start button is used to close the contacts again).. meaning that
> a commonly available normally closed (momentary open) switch with the proper
> voltage/current ratings wired in series with the coil circuit will also act
> as a Stop switch (E-Stop or other terminology).. unless the contacts become
> stuck shut.. then the OHshit switch needs to be utilized.
>
> This isn't the standard method commonly used in the US, for
> starting/stopping a machine motor, but it is a cheaper way to produce a
> motor starter.

That's the plan...

> Cheers,
> WB

Thanks,
Dave

==============================================================================
TOPIC: Tek 465
http://groups.google.com/group/sci.electronics.repair/t/b9f473fde6856891?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Aug 29 2011 10:08 pm
From: "Wild_Bill"

Dunno if the need will arise, but Sphere in Canada has a lot of online info
wrt Tek equipment (and numerous other brands) parts, parts cross-reference
lists, etc.

http://www.sphere.bc.ca/test/tek1.html

--
Cheers,
WB
.............

"Mark Zacharias" <mark_zacharias@labolgcbs.net> wrote in message
news:4e58de02$0$2960$a8266bb1@newsreader.readnews.com...
> Just bought a Tek 2246 on the 'Bay. This means the 465 will probably need
> to be sold, assuming the new one is OK and all.
>
> I would entertain serious offers from the good folks who know me here on
> the Group (USA only, please) prior to putting it up on eBay.
>
> Probably about 175.00 plus freight.
>
> Yes, this is the same 'scope Mr. Yanik helped me with recently. Replaced a
> bad bridge rectifier.
>
> Everything works great, bright sharp trace, no burns. Physical condition
> very good, nothing bent or broken, minor scuffs around the case but not
> involving the face. I have several versions of the manuals etc on PDF.
>
> Any questions please ask.
>
> Thanks.
>
>
> Mark Z.
>
> --
> "I can't die until the government finds a safe place to bury my liver."

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