Resonance

[Phil]

Here is another one for Bob

While the big Hegner is out of action, I wheeled out the small Hegner to do some cutting.

While the motor is running with the blade under tension, the noise sounds like "resonance" (the closest description that I could find.)

Any idea what could cause it?
The machine runs smoothly.

 

[Malc2098]

Is that description the same sounds as a twin engined aircraft humming, or beating was we guitarists call it?

It occurs when two close sound sources are just a couple of herz different from each other.

 

[Phil]

Malc, it sounds like a volume switch being turned louder then softer (closest description)

 

[Malc2098]

Malc, it sounds like a volume switch being turned louder then softer (closest description)

Tremelo.

 

[9fingers]

Malc has got it in one!

you might be able to experiment by adding a little extra weight on one of the moving parts and seeing if that raises the beat frequency to a more acceptable point.

Bob

 

[Phil]

Thanks Malc & Bob.

Maybe I will stick to the current beat

 

[Phil]

Machine running with top arm connected and blade inserted


[youtube]Rd4CMi-0VlQ[/youtube]


Top arm disconnected

[youtube]xi9lAvhQXP8[/youtube]

So, the problem seems to be related to the top arm and driving mechanism.
Will have a look.

 

[droogs]

check the pivot point at the back of the top arm, could be a crack

 

[Phil]

check the pivot point at the back of the top arm, could be a crack

Will do, thanks.

I will strip everything off and inspect, both arms and drive.