Relay - SS vs Mechanical

[Jason James]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:2t3b0mF1q772mU1@uni-berlin.de...

"Jason James"
"Phil Allison"

** All relays *wear out* - contacts have a limited switching life.

An argument like this has to be put into context.



** It is not an "argument" you tedious fuckwit - it is a simple fact
and
is quoted in the maker's specs.

............ Phil

The relays which operated on speech in what we called 'audio operated
relay' modules (used for a number of monitoring and Retx functions in the
past) literally operated and relaxed millions of times. They were just a
normal flat cct board unit. Their reliability was phenomonal....

Anyway Phil,...go back to the spec sheets.

Jason

 

[Phil Allison]

"Jason James" = utter imbecile

"Phil Allison"

** All relays *wear out* - contacts have a limited switching life.

An argument like this has to be put into context.


** It is not an "argument" you tedious fuckwit - it is a simple fact
and is quoted in the maker's specs.

............ Phil


The relays which operated on speech in what we called 'audio operated
relay' modules (used for a number of monitoring and Retx functions in the
past) literally operated and relaxed millions of times. They were just a
normal flat cct board unit. Their reliability was phenomonal....

** SO FUCKING WHAT ??????

An isolated and exceptional example like that proves absolutely **NOTHING**
about others !!!!!!

Clearly you know nothing about relay failures since YOU have never seen a
relay fail !!!!!!!

How mind numbingly ***stupid*** you are !!!!

Anyway Phil,...go back to the spec sheets.

** Piss off you PITA wanker.




............ Phil

 

[Geoff C]

"Jason James" <vellicet@bigpond.com> wrote in
news:2t3modF1r3epaU1@uni-berlin.de:

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:2t3b0mF1q772mU1@uni-berlin.de...

"Jason James"
"Phil Allison"

** All relays *wear out* - contacts have a limited switching
life.

An argument like this has to be put into context.



** It is not an "argument" you tedious fuckwit - it is a simple
fact
and
is quoted in the maker's specs.

............ Phil

The relays which operated on speech in what we called 'audio operated
relay' modules (used for a number of monitoring and Retx functions in
the past) literally operated and relaxed millions of times. They were
just a normal flat cct board unit. Their reliability was
phenomonal....

Anyway Phil,...go back to the spec sheets.

Jason

Hate to join the thread late but noticed the argument over reliability of
mechanical relays vs. SSR's. In my experience the reliabilty of mech
relays is not re-assuring, as a designer. Equipment I design must go into
corrosive, dusty and humid environments. (typical labs anywhere in the
world). I have seen many more mech relays fail than SSR's. The data
sheets for mech relays will tell you how unreliable they are if you dig
in to them. Not allowed to have too much or too little current, too small
OR too big a voltage etc.

Most failures IME have been contacts sticking, gumming or relaxing. Even
a relay soldered into a PCB at a crooked angle may not actuate properly
in early duty due to stresses in the base.

It is horses for courses anyway. SSR's excell in switching in
applications where wearout failures are undesirable. For extreme voltages
or low leakage a mech relay may be a better choice. Once an SSR is in
service, its reliability is high. This must be expected. It is sealed, no
moving parts and no contacts to gum up. I have seen stuff with mech
relays returned from field with insect nests gumming them up too!

 

[Phil Allison]

"Geoff C"

Hate to join the thread late but noticed the argument over reliability of
mechanical relays vs. SSR's. In my experience the reliabilty of mech
relays is not re-assuring, as a designer. Equipment I design must go into
corrosive, dusty and humid environments. (typical labs anywhere in the
world). I have seen many more mech relays fail than SSR's. The data
sheets for mech relays will tell you how unreliable they are if you dig
in to them. Not allowed to have too much or too little current, too small
OR too big a voltage etc.

Most failures IME have been contacts sticking, gumming or relaxing. Even
a relay soldered into a PCB at a crooked angle may not actuate properly
in early duty due to stresses in the base.

It is horses for courses anyway. SSR's excell in switching in
applications where wearout failures are undesirable. For extreme voltages
or low leakage a mech relay may be a better choice. Once an SSR is in
service, its reliability is high. This must be expected. It is sealed, no
moving parts and no contacts to gum up. I have seen stuff with mech
relays returned from field with insect nests gumming them up too!

** It is *mildly* infuriating that an ignorant fool like Jason tries to
dispute what common sense alone tells you - and then attempt to shove his
mad ideas down the throat of someone experienced in the use of relays.

If anyone cares to look up my 'RMS Current Monitor" design (from the May
1997 issue of EA magazine) you will see how I prevented the problem of
relay contacts used for AC power switching arcing severely and rapidly
wearing out.

The neat "fix" I dreamt up in that design took the project from unworkable
to publishable.



BTW My first post in this thread gave the only real reason why an SSR
might be unsuitable for switching the AC supply to some unspecified
appliance.

" ** A 20Amp SSR uses a large triac to do the actual AC switching -
these have minimum current ratings as well as maximum ones. Make sure the
appliance does not have a low current standby mode that derives its power
via a small iron core transformer ( eg a microwave oven) . The triac in
the SSR may not operate this tranny - or worse burn it out by only
operating during one half cycle so feeding it with a large DC component and
a small AC one. "




................ Phil

 

[Mike Harding]

On Tue, 12 Oct 2004 22:57:46 +1000, "Phil Allison"
<philallison@tpg.com.au> wrote:

Any day you can avoid using one and use a SSR or other electronic switch is
a good day.

In the vast majority of cases I would agree with you
however relays do still have a place in certain high
frequency applications (although less so than they
use to) and they are more tolerant to overload than
thyristors/triacs.

Mike Harding

 

[Jason James]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:2t3tc0F1q8emdU1@uni-berlin.de...

"Geoff C"


Hate to join the thread late but noticed the argument over reliability
of
mechanical relays vs. SSR's. In my experience the reliabilty of mech
relays is not re-assuring, as a designer. Equipment I design must go
into
corrosive, dusty and humid environments. (typical labs anywhere in the
world). I have seen many more mech relays fail than SSR's. The data
sheets for mech relays will tell you how unreliable they are if you dig
in to them. Not allowed to have too much or too little current, too
small
OR too big a voltage etc.

Most failures IME have been contacts sticking, gumming or relaxing. Even
a relay soldered into a PCB at a crooked angle may not actuate properly
in early duty due to stresses in the base.

It is horses for courses anyway. SSR's excell in switching in
applications where wearout failures are undesirable. For extreme
voltages
or low leakage a mech relay may be a better choice. Once an SSR is in
service, its reliability is high. This must be expected. It is sealed,
no
moving parts and no contacts to gum up. I have seen stuff with mech
relays returned from field with insect nests gumming them up too!



** It is *mildly* infuriating that an ignorant fool like Jason tries to
dispute what common sense alone tells you - and then attempt to shove
his
mad ideas down the throat of someone experienced in the use of relays.

If anyone cares to look up my 'RMS Current Monitor" design (from the
May
1997 issue of EA magazine) you will see how I prevented the problem of
relay contacts used for AC power switching arcing severely and rapidly
wearing out.

The neat "fix" I dreamt up in that design took the project from unworkable
to publishable.



BTW My first post in this thread gave the only real reason why an SSR
might be unsuitable for switching the AC supply to some unspecified
appliance.

" ** A 20Amp SSR uses a large triac to do the actual AC switching -
these have minimum current ratings as well as maximum ones. Make sure the
appliance does not have a low current standby mode that derives its power
via a small iron core transformer ( eg a microwave oven) . The triac in
the SSR may not operate this tranny - or worse burn it out by only
operating during one half cycle so feeding it with a large DC component
and
a small AC one. "

............... Phil

An excellent reason to use a relay FFS.

Incidently,...did you force the 'arcing' relay to only release at crossover
by using (of all things) an in-phase triac to control the coil?

Jason

 

On 6 Oct 2004 21:39:14 -0700, rg26ce1991@hotmail.com (Russell
Griffiths) wrote:

Greetings.
If I am understand you right, you are planning to build the energy
meter without buying the kit.

Have you been able to buy a ADE7756AN chip?

I contacted Analog Devices and was told their minimum order was 25 chips.

Russell Griffiths.

No, I've bought the DS kit, and the brown out protection is an
optional extra. (!)

The case is not the original one specified, which I would have
preferred, as the original is a lot more robust than the 'instrument
case' DS uses.

I think Altronics sells the kit as well, and probably with the case SC
used.

Good luck...

- Rob.

 

[Phil Allison]

"Jason James" ..

"Phil Allison"

" ** A 20Amp SSR uses a large triac to do the actual AC switching -
these have minimum current ratings as well as maximum ones. Make sure
the
appliance does not have a low current standby mode that derives its power
via a small iron core transformer ( eg a microwave oven) . The triac
in
the SSR may not operate this tranny - or worse burn it out by only
operating during one half cycle so feeding it with a large DC component
and
a small AC one. "


An excellent reason to use a relay FFS.

** That is what a complete fool like Jason would say.

The solution is to add a standing, resistive load to the SSR - a small
lamp or a 10 kohm resistor - problem gone.

Incidently,...did you force the 'arcing' relay to only release at
crossover
by using (of all things) an in-phase triac to control the coil?

** Even dumber that your previous fuckwit posts.



............... Phil

 

[Jason James]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:2t6u99F1s2omiU1@uni-berlin.de...

"Jason James" ..

"Phil Allison"

" ** A 20Amp SSR uses a large triac to do the actual AC
itching -
these have minimum current ratings as well as maximum ones. Make sure
the
appliance does not have a low current standby mode that derives its
power
via a small iron core transformer ( eg a microwave oven) . The triac
in
the SSR may not operate this tranny - or worse burn it out by only
operating during one half cycle so feeding it with a large DC component
and
a small AC one. "


An excellent reason to use a relay FFS.



** That is what a complete fool like Jason would say.

The solution is to add a standing, resistive load to the SSR - a
small
lamp or a 10 kohm resistor - problem gone.



Incidently,...did you force the 'arcing' relay to only release at
crossover
by using (of all things) an in-phase triac to control the coil?



** Even dumber that your previous fuckwit posts.

You can use the idea.

Jason

 

[Phil Allison]

"Jason James"

"Phil Allison"

Incidently,...did you force the 'arcing' relay to only release at
crossover
by using (of all things) an in-phase triac to control the coil?


** Even dumber that your previous fuckwit posts.

You can use the idea.

Jason

** What - as a desperate substitute for toilet paper ????




................... Phil

 

[Jason James]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:2t7au7F1sfpkpU1@uni-berlin.de...

"Jason James"
"Phil Allison"

Incidently,...did you force the 'arcing' relay to only release at
crossover
by using (of all things) an in-phase triac to control the coil?


** Even dumber that your previous fuckwit posts.

You can use the idea.

Jason



** What - as a desperate substitute for toilet paper ????

.................. Phil

Hey,.. too much information. Try using those relay spec sheets which
high-light "this relay will wear out" as an arse-wipe.

Jason

Jason