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Gigavac GV200QA humming, buzzing noise

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Hey,

another questions regarding the contactor of my EV-build.
I used the Netgain Hyper9 system with the SME ACX1 inverter.
So there is the main contactor GV200QA. As soon the inverter is powered and has gone through self checks it activates the contactor.
But it makes a really "loud" humming noise as soon as activated.
I can control the pich of the noise when changing the frequency in the program, also the volume if I turn down the holding voltage. But if I turn it down to much the contactor loses connection when there are vibrations in the vehicle.
The other one (GV200MAB) I used controlled by the Orion 2 BMS doesn't make such noise.

Is it right, that the noise is normal due to the low frequency PWM given by the inverter?
Didn't hear such noise in other EV builds so wondering if this could be an issue.

Hope for your thoughts on this.
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Discussion Starter · #7 ·
Just like a music box mechanism, if you have the contactor sitting on a large piece of metal, it could act as a mechanical amplifier. You may want to revise how you have your contactor mounted as another approach.

Another method is to crank the PWM up to 14kHz...that way it only drives kids nuts with the sound 😂
Also considered that.
But that's not the case, since I mounted this one on a wood plate and I also tested it on a aluminum plate before - same noise.
So it definetely comes from the contactor itself. It's mounted properly, the bolts are tight so no vibrations or other things from that.

Tried to rise the PWM but it stops at 1000Hz. So no chance to blow the kids ears:geek:
 

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Discussion Starter · #9 ·
So today I called the German support and he refered me to the application notes. He didn't remember any case of humming contactors either and said it shouldn't be normal.
So I'm waiting for the US support to answer.

Mounting it tight couples it to the mounting plate. Does it make the same level of sound while dangling in the air?

Are you mounting it dead center on the plate?
Tried it today. So I dismounted it and tested - the noise gets quieter. So the wooden plate definately amplifies the noise but it's still there.
I made a short video to demonstrate: contactor video
 

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Discussion Starter · #12 ·
So I got an answer from the US support today.
He said that the GV200QA is normally driven with 25kHz so people can't hear it.
With 430Hz is way too low and the sound is the contactor opening and closing at this speed.
But the maximum frequency I can put in my settings is 1kHz.
I don't know why and I also can't understand why nobody else has this problem because it's an extremly spreaded kit for electric car conversions.
Seriously, try adding a capacitor. Connect it in parallel with the coil - it will absorb the pulses. Just make sure it's rated for the same (or above) voltage as the coil, and mind the polarity.
Actually don't want to test this till I really know there's no other option to tweak this software.
But as I see there won't be another chance...
 

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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’t 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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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 100µF 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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