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Posted by Noon-Air on September 15, 2006, 11:20 pm
> gofish@gonefishin.net wrote:
>> 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.
>
> They're usually replaced with newer technology long before they break,
> Fish. I have some in the field for 20+ years running 100+ hp motors.
> They're over-engineered, for sure... but I've seen very rare failures.
>
>>> 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.
yup
> Really... and what do you do when you find it's the motor or the driver?
> I'm curious?
Replace the part thats bad
>>> 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....
>
> A VFD is an inverter... not a chopper. It's capable of running the motor
> faster than the line frequency... something a chopper cannot do. It's also
> capable for delivering more torque, and ramping the motor... under
> control.. up and down. Something a chopper cannot do.
>>
>>
>>> 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.
>
> I really don't buy that. Real VS motors have not been around that long in
> resi applications, have they? You'd have to give me some more info before
> I believe that.
Rheem has had ECM blower motors in high end, resi equipment since 1997
>>> 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.
They might make a killing on the motors, but the manufacturers are clamping
down on swapping out (warranty)"bad" ECM motors because BJJB hasn't been to
the classes that the manufacturer puts on that tells you how/what to do with
them.
>> more horseshit. What would an electrician from Indianna know about
>> nationwide HVAC field training? Perhaps you have links to back up
>> your biased opinions?
>
> I know that many HVAC techs I've run into... particularly in the resi
> trade... have little skills about discrete controls in general and even
> less about something as advanced as analog. Granted, that's in my little
> corner of the World here but I suspect factory training is the same
> throughout the country.
>
>>
>>> 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.
>> :))
>
> Fish.. you know me. I don't discuss things I don't understand. I ask for
> help when I need it. Don't throw that HVAC trade stuff at me... this is a
> controls problem of which I am very familiar. I don't care whether it's
> running a fan or a 500 hp. compressor motor... the concepts are the same
> thing.
>
> Building these controls onto a easy-replace motor that the customer will
> be forced to pay exorbitant rates to replace is a scheme. It makes
> ill-trained techs have a easy answer... and it makes the likes of
> GE-Regal/Beloit a lot of money.
>
> I'm not fooled.
>
> BTW, the McQuay units we installed last year have Toshiba drives in them.
> I'm happy with that...
>
> Jake
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