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Thanks for making my point....
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The "hold voltage parameter" is not correctly set
Okay, I think I caught up with your idea now. Lower duty cycle forms a secondary frequency, like 25Hz for 25%, which may be audible. That is plausible, but if one wants to utilize the economizer, capacitor is still the way to fix it. I think the reason PWM outputs in these things aren't smoothened by caps is because caps need to be picked for each load, which isn't known ahead of time.

Hold on, I wrote nonsense about 25Hz... need to think for a moment :D

Okay, so I think this last idea is swill wrong, and my first thought was correct.

Let's say we want to have 12v holding voltage from a 48v (nominal) pack. That's the 25% the voltage, and we achieve it by using 25% duty cycle of the output. Now we have a 400Hz PWM driver, which means out of 400 possible pulses, it needs to put out every 4th pulse in order to maintain 25% duty cycle. If we write it like a binary number, it would look like this :

1 0 0 0 1 0 0 0 1 0 0 0 0 <--- 400 times every second. I don't think that sub millisecond gap would affect audibility of the signal.
 

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Discussion Starter · #23 ·
No.

He disclosed that the contactor is actually opening and closing when actuated....
Maybe expressed that a bit sloppy.
The contactor is closed after I fire up the vehicle. I can drive without any problems beside the noise.
The Gigavac vendor told me the following:

What frequency is the GV200QA contactor coil being driven with? Gigavac uses 25kHz so that it can鈥檛 be heard (by humans).
-Brian


I told him that I run it with 430Hz and I'm not able to go above 1kHz due it's limited by the programm
Then he wrote the following:

430 Hz is too low. The sound you hear is likely the contactor opening and closing rapidly.
You could use a GV200FA and the same output by setting the PWM duty cycle to 100% (48vdc).
-Brian
 

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Discussion Starter · #24 ·
I also went through the Hyper9 thread from OR-Carl where 4Foxtrot wrote the following:

6. Beg Hunter for the OEM /dealer version of the SME Tau software .. Warning: you CAN kill yourself/system ... but at the very least it allows you to lower the frequency of the contactor to make it almost silent !!! (and adds many more useful options). I cant post the software, but HERE are the help files which show capabilities.

So I guess he lives with that noise.
Tomorrow (today better said) I will go through all these things and be right back when I got any news.
 

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It's really just micro-vibrating. Kind of like connecting a small DC motor to a source of audio signal - it will play it like a speaker.
Then you may be hearing vibration of the coil. But yeah, Gigavac is expecting you to be able to set the PWM frequency outside of human hearing range (hence 25khz). It looks like you can't do that in the SME software.
 

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They better not be. That's my point, and what Gigavac said. That they are opening and closing. Reread what they wrote:

"430 Hz is too low. The sound you hear is likely the contactor opening and closing rapidly"

It would be an interesting, albeit shortlived, way to control motor speed
 

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"Coil vibration like a loudspeaker" is simplifying it for the average joe.

But that is not what they said, is it?

And nobody is going off and changing the f*cking duty cycle to 80% on the holdin to see if the sound goes away, are they? Take 2 minutes of effort to check that. 2 many minutes.
 

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Discussion Starter · #31 ·
So today I reprogrammed all parameters to check if they are set 100% right.
Then put in the capacitor but this doesn't work. The inverter falls into Error mode and says "contactor open/short".
Tested it with a 60V 100碌F capacitor, it was the only one with that specs to fit in my selection.
So the only way will be to turn down the frequency to 120Hz and try to mount it in a isolating way.
 

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Discussion Starter · #35 ·
It can't be disabled (at least not for me although it's the OEM version) since the inverter needs to output the signal for the contactor. If there is any fault, it jumps into failmode in order no HV is passing through. So I think it's kind of a safety feature (bug ;)).
 

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Discussion Starter · #36 ·
It can't be disabled (at least not for me although it's the OEM version) since the inverter needs to output the signal for the contactor. If there is any fault, it jumps into failmode in order no HV is passing through. So I think it's kind of a safety feature (bug ;)).
 

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It can't be disabled (at least not for me although it's the OEM version) since the inverter needs to output the signal for the contactor. If there is any fault, it jumps into failmode in order no HV is passing through. So I think it's kind of a safety feature (bug ;)).
I just meant can the PWM be disabled, not contactor control. Like set to 0hz or something. Otherwise I'd want to think about some PWM detecting relay to convert to a solid voltage to avoid PWM.
 
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