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Carrier variable speed motor, duct transitions - any problems?

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Carrier variable speed motor, duct transitions - any problems? Todd H. 09-14-2006
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Posted by Todd H. on September 15, 2006, 5:03 pm

> > Cool. Nice to meet you. BS EE here, so we can talk geek to geek.
> > :-)
> >
> Todd..
>
> think about the EMI and surge suseptability issues of the variable
> speed control electronics... and how much they cost to repair after the
> lightning storm...vs how much energy savings/comfort they may or may
> not buy you...

Yeah... it's true. Although with a 10 year warranty (Bryant anyway),
it gets a little easier to stomach. :-) And with underground service
here, we've been pretty lucky thus far with being (relatively
speaking) strike and surge free. But it is certainly a risk vresus
the tried and true single speed systems.

The Fanhandler+Baldor route might be worth investigating further. But
given the temp differences in this Colonial here, variable speed has
some compelling appeal to me. Like anything it's a calculated risk
right?

I agree though that the cost savings argument is a red herring with
variable speed. It's really mostly about comfort while reducing
energy use. Whether that reduction in energy use translates to money
savings depends on whether the damned thing breaks and requires
repair. :-)

Best Regard,s
--
Todd H.
http://www.toddh.net/

Real Goods Solar, Inc.
Posted by Jake on September 15, 2006, 7:18 pm
>
> The Fanhandler+Baldor route might be worth investigating further. But
> given the temp differences in this Colonial here, variable speed has
> some compelling appeal to me. Like anything it's a calculated risk
> right?
>

A Fanhandler with a good motor will give you the same or better results
than a OEM VS setup... I'd bet on it. It does the same thing, but the
design is not on-board the motor and can be more efficient... and reliable.


> I agree though that the cost savings argument is a red herring with
> variable speed. It's really mostly about comfort while reducing
> energy use. Whether that reduction in energy use translates to money
> savings depends on whether the damned thing breaks and requires
> repair. :-)

A integrated, on-board VS will break, Todd. It's an frequency chopper
mounted on a motor housing, for Gods sake.

It also makes things more difficult for the standard field service guy
to diagnose. I don't know the specifics here but it looks to me like the
test is "go" or "no go". The tech doesn't know if it's the controller,
or the "chopper", or the motor. He'll just replace them all in one neat
package for $800.00... so it can fail again in a few years.

Note how tricky a PWM power supply is.... These guys are not gonna have
a 'scope out there. Thing is.. if you did... the thing could probably be
fixed for $10 bucks instead of $800.

From the cheap plug-in control wiring harness, to the inadequate
assurance of ventilation... it's a bad design, and time will prove it.

The OEM's should have gone with a separate 'module' complete with
on-board diags... but they didn't because the field training is weak on
this stuff (in resi) and they can make a killing on motors.

Sorry... I'm not sold. And I'm grouchy tonight.

Jake

Posted by =?iso-8859-15?Q?Tekkie=AE?= on September 15, 2006, 7:45 pm
Jake posted for all of us...

> Sorry... I'm not sold. And I'm grouchy tonight.
>
Constipation?
--
Tekkie "There's no such thing as a tool I don't need."

Posted by PrecisionMachinisT on September 15, 2006, 10:04 pm


> "There's no such thing as a tool I don't need."

Pretty sure gonna buy this one next week:

http://tinyurl.com/f6mhb

Winning bidder sniped me, but has apparently now backed outa the deal.

--

SVL





Posted by on September 15, 2006, 10:00 pm
Jake wrote:


>
>A integrated, on-board VS will break, Todd. It's an frequency chopper
>mounted on a motor housing, for Gods sake.


NEWS FLASH Jake. Every fucking thing built by human beings will
break. The highly touted ABB VFD's you put in? There gonna break
someday, bet your life on it.


>
>It also makes things more difficult for the standard field service guy
>to diagnose. I don't know the specifics here but it looks to me like the
>test is "go" or "no go". The tech doesn't know if it's the controller,
>or the "chopper", or the motor. He'll just replace them all in one neat
>package for $800.00... so it can fail again in a few years.

Once again, unadulterated horseshit. Competent techs have a VS
motor tester kit that tells them whether its the GE motor or the
propriatary electronics package thats defective.



>
>Note how tricky a PWM power supply is.... These guys are not gonna have
>a 'scope out there. Thing is.. if you did... the thing could probably be
>fixed for $10 bucks instead of $800.


Now I'll bet you're gonna tell us the VFD's you push dont utilize PWM
as well......a VFD is a frequency chopper for Gods sakes....


>
> From the cheap plug-in control wiring harness, to the inadequate
>assurance of ventilation... it's a bad design, and time will prove it.


more horseshit.. The VS motor in my furnace has been running
non-stop 24/7 for the last 10 years. I run constant fan, and I MAY
remember to change the 2" pleat filter 2x yearly.

>
>The OEM's should have gone with a separate 'module' complete with
>on-board diags... but they didn't because the field training is weak on
>this stuff (in resi) and they can make a killing on motors.

more horseshit. What would an electrician from Indianna know about
nationwide HVAC field training? Perhaps you have links to back up
your biased opinions?

>
>Sorry... I'm not sold. And I'm grouchy tonight.
>
>Jake

Who cares if you're sold or not? When you get 15-20 years under your
belt as an HVAC service tech, you MAY have a little more credibility
with people who are actually in the trade today.

ps- if you're still grouchy, wait til morning before you read this.
:))

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