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Thread: New VFD announced by Powtran
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21st Jun 2019, 12:10 PM #16Most Valued Member
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21st Jun 2019, 01:13 PM #17Member: Blue and white apron brigade
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The 500 series brochure I have says
Screen Shot 2019-06-21 at 9.58.15 am.png
There's clearly a typo in the second line where the first 480V should be 380V
The 500 manual says
Screen Shot 2019-06-21 at 10.06.12 am.png
Still trying to get my head around this - at its simplest I guess it could mean anywhere from 187 to 264V???, or maybe 226 +/- 38V???
Can't imagine them using different components for different 220 and a 240V versions but who knows.
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21st Jun 2019, 03:21 PM #18
Ya, kind of funny.
Here is the reply I received from Nicole today.
"Yes , at present we only manufacture the 380v for PI150 .
All products are begin from 380v , then we design 220v , 480v , like this .
We still need one or two month to prepare for the 220v , I will let you know when it is ready for market . "
So it's down to the 9130 or 500 for me...they both look nice.
Cheers
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21st Jun 2019, 05:26 PM #19Golden Member
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21st Jun 2019, 06:54 PM #20
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22nd Jun 2019, 10:31 AM #21Most Valued Member
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Taken literally those numbers are right John. But it still doesn't make sense to me. If you're going to specify a range you don't then add a tolerance. And I'd be surprised if the VFD would run on 187V.
Chris
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22nd Jun 2019, 11:00 AM #22Member: Blue and white apron brigade
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I agree.
When I served on an international scene panel we moved some key chemical data from X+/-x, to (X+y/-z) with X being the most likely number, while some data was moved to a range ( A to B).
The "range" concept threw convention scientists into a tiz and some said "but what actual number should we use when we do a calculation" and when we said you have to use both to get the range of your output calculation that upset them even more. "Can we pick the mid point" they said, "yes you can, but that won't tell you your output tolerance" we replied. The reason a more specific number could not be provided was because of what is called "the [limited] state of knowledge". Picking the mid point of the range to use in calculations assumes that this number is more likely that others but this is not always the case. Many natural data distributions are not distributed about a specific value either because that is how things are, or sometimes because we have incomplete inputs.
. And I'd be surprised if the VFD would run on 187V.
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22nd Jun 2019, 03:10 PM #23
Hi Bob, Guys,
I don't think the motor being able to handle the voltage to be an issue. Since the output is a variable frequency modulated pulse train. A bit like a radio transmitter with a nominal 50 Hz modulation. The modulation frequency, 25 to 200 Hz, being changed to control the speed, and the carrier level being adjusted according to the load variations. I suspect the "Vector" bit is essentially the simultaneous varying of both in order to cope with changing load conditions.Best Regards:
Baron J.
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22nd Jun 2019, 05:54 PM #24Most Valued Member
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22nd Jun 2019, 08:15 PM #25
Hi Chris,
Power is a function of voltage times current. From what little reading I've done, it seems that the VFD either auto measures the motor characteristics or you have to enter them manually. So realistically any voltage around nominal will do.
Internally the VFD is a rectifier plus capacitor bank providing a DC voltage that is chopped at some frequency. I did read that a carrier frequency of 10 or 20 Khz was mentioned. I would imagine at those frequencies it would allow the motor impedance to be determined and that value used to set the output parameters.
I used to have a number of technical documents by "Texas Instruments" on motor control systems and circuit design for them. I have no Idea if they are still available, they went into great detail about single and multiple phase motor control.Best Regards:
Baron J.
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22nd Jun 2019, 09:04 PM #26Most Valued Member
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It's beyond my level of knowledge John. My VFD has a variable carrier frequency. Factory default is 6kHz. I think they make it variable so you can find a frequency that doesn't drive you crazy. I know around 4kHz makes me want to jump out a window.
Chris
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22nd Jun 2019, 11:06 PM #27Member: Blue and white apron brigade
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4kHz is a primary frequency for grouped consonants sounds ( "digraphs" - a group of two consonant letters standing for a single sound). Many of these involve a hissing type sound, like the "tch" in "sketch" and "ch" in "cheese" and sh in "ship". Even though the human ear is not as sensitive to these as they are to sound around 1kHz, some humans are extra sensitive to these types of noises. This is why air rushing into dust collector ports gives me the pips.
As an aside folks (like me) with hearing loss around 4kHz find it difficult to distinguish sources and words containing digraphs in a noisy group. Listening then becomes difficult/stressful and mentally tiring.
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23rd Jun 2019, 03:46 AM #28
Hi Chris, Bob,
I know what you mean, 4 Khz is a little bit low, so is 6 Khz for that matter ! I repaired a golf cart drive for a friend and he complained bitterly about the whine that the motors produced under load. I couldn't make the drive frequency high enough for it to become inaudible.
Like you Bob, I have issues with hearing what is said to me in a noisy environment, my hearing aids don't help either, they just make everything louder.Best Regards:
Baron J.
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27th Jun 2019, 01:49 AM #29
Keeping everyone up to date...Nicole informed me they have discontinued the PI160 series and are only shipping what they have left in stock, and they are out of the 1R5G1Z. Waiting to hear if they have a 2R2.
FYI
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8th Jul 2019, 12:09 PM #30Golden Member
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I am also interested in a VFD for my CNC mill - 2.2 kW 240 V to 240V 3-ph.
No fancy complications needed.
My original Huangyang (SG) has a fan that starts/stops automatically, my newer SAJ (lathe) operates the fan continuously.
What does the fan do on the Powtrans ?
John
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