Dewalt DCD760KL squealing?

[Cliff Holmes]

I have a question for any Dewalt li-ion owners: I'm testing a Dewalt
DCD760KL. When the drill is running at really low speeds, it gives off a really loud, high-pitched squealing noise. Does your drill do this, too?

[Jamie Buxton]

I don't have one of those drills, but I did have another DeWalt drill that started making that sound after several years of use. It turned out that one of the bearings was seizing up, so the motor was spinning the bearing in the plastic housing.

[Cliff Holmes]

This one is brand new. And it's only on very low speeds, maybe 200 rpm or less.

[Cliff Holmes]

Thanks for the tip, I'll check it out.

[Dave Lash]

I have an older (4-5 years) 14.4 volt Dewalt 1/2 inch drill that emitted the high pitch squeel when the triger is just slightly depressed; it dosn't sound like a mechanical sound, I think it is fron the electronic speed controll. Once the drill is running faster the normal mechanical drill noise covers the squeel. An older (10 years) 12 volt 3/8 inch dewalt Drill I own dosn't make that squeeling noise.

[Dan Friedrichs]

I have an older (4-5 years) 14.4 volt Dewalt 1/2 inch drill that emitted the high pitch squeel when the triger is just slightly depressed; it dosn't sound like a mechanical sound, I think it is fron the electronic speed controll. Once the drill is running faster the normal mechanical drill noise covers the squeel. An older (10 years) 12 volt 3/8 inch dewalt Drill I own dosn't make that squeeling noise.

+1. It's the switching electronics. There are likely a few transistors inside that get switched on and off at around 20kHz - the harder you press the trigger, the longer they stay on each cycle. You're hearing the transistors switch. If you opened the drill and disconnected the motor, you'd hear the same squeal throughout the range of the trigger - the motor noise just drowns it out at higher speeds.

There's probably no good explanation of why they didn't set the frequency higher (so that you couldn't hear it). Maybe it let them buy parts that were a little cheaper...