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Posted by Noon-Air on June 7, 2007, 9:07 pm
show/hide quoted text
>>Noon-Air wrote:
>>>> There is no 'linear' control. 60 or 100 percent? Geeze....
>>> Its a resi job......the manufacturer makes them, I just install them.
>>I'm not 'dinging' you, Steve.... But please remember the manufacturers
>>are not doing right by the consumers here. I don't blame Copeland, either.
>>The OEM's have a great concern the field techs out here have no ability
>>to deal with complex electronics like VFD's and digital control.
>>I just want to know if that's justified, or not..
>>Jake
> You gotta be kidding me. The Average Residential 'Tech' isn't
> qualified to properly level the pad to set a condensor on. The A.R.T.
> is concerned about generating enough sales to keep the boss of his
> ass, and how many more calls will he have to take today, and what's
> the safest way for him to avoid having a call-back ( condeming the
> whole system is pretty safe, he figures ).
> The A.R.T. couldn't tell you what a VFD is, has never seen
> one, barely knows how to work a computer if at all, wouldn't now a PID
> if it jumped up and bit him in the ass, has no clue what a 'control
> signal span' is, no clue what a ramp is, no clue what a PLC is, etc
> etc.
> Face it - residential work is the dog's ass of the industry -
> it's run-your-ass-off in the summer, look-for-make-work-shit-to-do in
> the spring and fall, run-your-ass again in the winter, until you're
> too old to do it any more.
> The A.R.T. is accustomed to little split systems < 5 ton, has
> often never worked on anything larger, that have maybe one small
> board, 2 relays, and 2 contactors, in total. Often the A.R.T. is
> confused as all hell if he's confronted with so much as a different
> brand than the one he usually deals with.
Wait till the A.R.T. runs across the controls in a Rheem/RUUD JEZ model :-)
They got a mother board and the heat pumps have a daughter board in them
too.
They even engage the on-board compressor relay at the NULL(+/- 0) of the
sine wave.... I was impressed.
show/hide quoted text
> It's not like the work you do, Jake, with all the training,
> testing, supervision, variety, challenges, etc etc. It's all about
> 'How many calls did you run today ?', 'How many call-backs this month
> ?', and 'how many new systems did you sell today ?'. That's the
> business.
> --
> Click here every day to feed an animal that needs you today !!!
> http://www.theanimalrescuesite.com/
> Paul ( pjm @ pobox . com ) - remove spaces to email me
> 'Some days, it's just not worth chewing through the restraints.'
> 'With sufficient thrust, pigs fly just fine.'
> HVAC/R program for Palm PDA's
> Free demo now available online http://pmilligan.net/palm/
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Posted by .p.jm on June 7, 2007, 9:22 pm
wrote:
show/hide quoted text
>> The A.R.T. is accustomed to little split systems < 5 ton, has
>> often never worked on anything larger, that have maybe one small
>> board, 2 relays, and 2 contactors, in total. Often the A.R.T. is
>> confused as all hell if he's confronted with so much as a different
>> brand than the one he usually deals with.
>Wait till the A.R.T. runs across the controls in a Rheem/RUUD JEZ model :-)
>They got a mother board and the heat pumps have a daughter board in them
>too.
The ART will not even know that, not after having worked on a
dozen of them.
show/hide quoted text
>They even engage the on-board compressor relay at the NULL(+/- 0) of the
>sine wave.... I was impressed.
And the benefit of that, electrically speaking ?
--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
|
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Posted by Noon-Air on June 7, 2007, 9:48 pm
show/hide quoted text
> wrote:
>>> The A.R.T. is accustomed to little split systems < 5 ton, has
>>> often never worked on anything larger, that have maybe one small
>>> board, 2 relays, and 2 contactors, in total. Often the A.R.T. is
>>> confused as all hell if he's confronted with so much as a different
>>> brand than the one he usually deals with.
>>Wait till the A.R.T. runs across the controls in a Rheem/RUUD JEZ model
>>:-)
>>They got a mother board and the heat pumps have a daughter board in them
>>too.
> The ART will not even know that, not after having worked on a
> dozen of them.
>>They even engage the on-board compressor relay at the NULL(+/- 0) of the
>>sine wave.... I was impressed.
> And the benefit of that, electrically speaking ?
No arcing at the contacts.... supposed to make them last 10 times longer
than a regular contactor
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Posted by .p.jm on June 7, 2007, 10:11 pm
wrote:
show/hide quoted text
>> wrote:
>>>> The A.R.T. is accustomed to little split systems < 5 ton, has
>>>> often never worked on anything larger, that have maybe one small
>>>> board, 2 relays, and 2 contactors, in total. Often the A.R.T. is
>>>> confused as all hell if he's confronted with so much as a different
>>>> brand than the one he usually deals with.
>>>Wait till the A.R.T. runs across the controls in a Rheem/RUUD JEZ model
>>>:-)
>>>They got a mother board and the heat pumps have a daughter board in them
>>>too.
>> The ART will not even know that, not after having worked on a
>> dozen of them.
>>>They even engage the on-board compressor relay at the NULL(+/- 0) of the
>>>sine wave.... I was impressed.
>> And the benefit of that, electrically speaking ?
>No arcing at the contacts.... supposed to make them last 10 times longer
>than a regular contactor
OK. Interesting. It assumes full closure in < 1/240 th of a
second ( one half of one half of the waveform, to achieve < 50 % of
the closing voltage ), IOW ~ 5 milliseconds physical travel time.
Hmmm..... And, what then about the AMPS at that instant ? Which are
thusly doubled ?
A regular contactor without that special treatment lasts ....
how long ? 10 years ? More ? So, their contactors last 100 years ?
Hmmm....... wish I had that kind of warranty on the needle of my
bullshit meter, which just got bent again :-)
Sorry, I call 'bullshit' ( On them, not you ) on that one. I
think it's a BS sales thing, and meaningless in the real world.
--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
|
|
Posted by Jake on June 8, 2007, 6:28 pm
.p.jm@see_my_sig_for_address.com wrote:
show/hide quoted text
> OK. Interesting. It assumes full closure in < 1/240 th of a
> second ( one half of one half of the waveform, to achieve < 50 % of
> the closing voltage ), IOW ~ 5 milliseconds physical travel time.
> Hmmm..... And, what then about the AMPS at that instant ? Which are
> thusly doubled ?
>
> A regular contactor without that special treatment lasts ....
> how long ? 10 years ? More ? So, their contactors last 100 years ?
> Hmmm....... wish I had that kind of warranty on the needle of my
> bullshit meter, which just got bent again :-)
>
> Sorry, I call 'bullshit' ( On them, not you ) on that one. I
> think it's a BS sales thing, and meaningless in the real world.
>
>
Paul and Steve...
This technique has been used and debated about for years in the controls
business... commonly called "half-sine".
The relay (or contactor) coil and the load are energized at half-sine to
minimize coil inrush and load inrush. Many times, this is also done at
'break' as well as 'make'.
There are a couple of problems with this technology, and that may be why
some OEM's have chosen not to use them...
Nasty harmonics can result if you have many units using this, or one
cycling frequently. Power factor is seriously screwed with... and large
loads may even need to be de-rated (low starting torque) for it to work
successfully.
Finally, some manufacturers have adopted this because they feel the cost
of the controls is cheaper than using heavier contactors. Many try to
use cheaper relay contacts as a justification.
It's a well-known fact that a contactor's mechanical life is about 5
times as much as the electrical (particularly contact) life. If the
OEM's don't try to use cheaper contactors and employ this technology, I
applaud them for doing so... in the right application.
Jake
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>>>> There is no 'linear' control. 60 or 100 percent? Geeze....
>>> Its a resi job......the manufacturer makes them, I just install them.
>>I'm not 'dinging' you, Steve.... But please remember the manufacturers
>>are not doing right by the consumers here. I don't blame Copeland, either.
>>The OEM's have a great concern the field techs out here have no ability
>>to deal with complex electronics like VFD's and digital control.
>>I just want to know if that's justified, or not..
>>Jake
> You gotta be kidding me. The Average Residential 'Tech' isn't
> qualified to properly level the pad to set a condensor on. The A.R.T.
> is concerned about generating enough sales to keep the boss of his
> ass, and how many more calls will he have to take today, and what's
> the safest way for him to avoid having a call-back ( condeming the
> whole system is pretty safe, he figures ).
> The A.R.T. couldn't tell you what a VFD is, has never seen
> one, barely knows how to work a computer if at all, wouldn't now a PID
> if it jumped up and bit him in the ass, has no clue what a 'control
> signal span' is, no clue what a ramp is, no clue what a PLC is, etc
> etc.
> Face it - residential work is the dog's ass of the industry -
> it's run-your-ass-off in the summer, look-for-make-work-shit-to-do in
> the spring and fall, run-your-ass again in the winter, until you're
> too old to do it any more.
> The A.R.T. is accustomed to little split systems < 5 ton, has
> often never worked on anything larger, that have maybe one small
> board, 2 relays, and 2 contactors, in total. Often the A.R.T. is
> confused as all hell if he's confronted with so much as a different
> brand than the one he usually deals with.