[remy_martian]

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 😂

 

[remy_martian]

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?

 

[remy_martian]

Yup...that's giant mosquito annoying 😂

 

[remy_martian]

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.

 

[remy_martian]

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....
😘

The "hold voltage parameter" is not correctly set

 

[remy_martian]

No.

He disclosed that the contactor is actually opening and closing when actuated....

 

[remy_martian]

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

 

[remy_martian]

"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.

 

[remy_martian]

What values did you set each of the parameters to?

 

[remy_martian]

Turn the hold voltage up from 11% to 48%

11% is too low and the contactor is dropping out. It's PERCENT not VOLTS.

edit: even if it's volts, turn it up past 11....to 48V you can fine tune this later.