View single post by DavidT
 Posted: Mon Oct 8th, 2012 02:26 pm
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DavidT

 

Joined: Wed May 2nd, 2012
Location: United Kingdom
Posts: 456
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Herb,
I've not measured Losi but I have measured several other receivers with embedded ESCs. It seems common for the PWM frequency to be around 1kHz. This has a bit of a whine. My receivers go up to 700Hz. I found a web site by a train enthusiast and electronics guru who listed many commercial mains controllers for trains and they used low frequencies around 100Hz. So I have 60 and 130Hz which are probably the best for trains, 300Hz just in case and 12hz which makes a 'pop pop' sound in my little boat.

The 60 and 130Hz settings make a 'gravel crunching' sound and I think the 300hz is fine too.

Capacitors can help reduce whiny ESCs. I got the impression from my tests that you need somewhere between 1uF and 100uF. This is easiest done with two tantalum or electrolytic caps. Since these are polarised you need two. The negatives of both need to be connected together and each positive goes to the motor terminals. Caps change the startup characteristics and the low frequncies I now have make a nicer sound so I've not pursued caps further.
dt.

Last edited on Mon Oct 8th, 2012 02:27 pm by DavidT

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