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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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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 馃槀
 

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I think I see what's happening.

You seem to be changing the frequency instead of the duty cycle.

You need to fire the contactor at 100% duty cycle, then back the duty cycle off a few dozen percent after a hundred or two milliseconds. The contactor SHOULD NOT be opening and closing. If it is, your duty cycle is too low in the power save portion of the cycle.
 

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I don't think that's correct. I was going through a bunch of that stuff with a Curtis 1236 controller recently. Contactor is driven via one of the PWM outputs, where duty cycle is used to adjust the output voltage to the coil. So like my battery nominal is about 50V, contactor has a 24V coil, so duty cycle is set for 50% for basically putting half the battery voltage to the coil. Then there is the second parameter for adjusting hold voltage in a similar fashion. THEN, on top of that, all PWM outputs on Curtis have an output frequency adjustment within a certain range. Changing that parameter has no effect on the duty cycle itself, just really how that duty cycle is achieved
Thanks for making my point....
馃槝

The "hold voltage parameter" is not correctly set
 

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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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