Variable speed cordless drills not variable?

[John Doe]

Hey (is for you),

Apparently all DeWalt variable speed cordless drill owners manuals say
this:

"NOTE: Continuous use in variable speed range is not recommended. It
may damage the switch and should be avoided."

What's that mean?

Thank you.

Here are some specific questions:

How serious are they?
Or is that like saying "always unplug your TV when not in use"?

What is that warning based on?

Is the switch bypassed when fully pressed?

Do they mean only when under heavy load?

Thank you.

Extraneous information, for what it's worth, this is my intended use.
I found a 36 V cordless hammer drill made by DeWalt, the bare tool is
very inexpensive. I already have three 12V 3.5AH Panasonic batteries
(need to make a battery holder for them). Planning to use that monster
drill for an in-line skate board/scooter motor. I'm sure it has enough
power. Even if their warning about variable speed is for real, it
should still work just fine IMO. A cordless drill fits the application
well for several reasons (inexpensive, rigorously designed to be light
weight, two or three speed settings which isn't a gear shifter but is
usable for varying terrain, and a highly variable clutch to help
prevent throwing the rider off-balance).

 

[John Popelish]

Hey (is for you),

Apparently all DeWalt variable speed cordless drill owners manuals say
this:

"NOTE: Continuous use in variable speed range is not recommended. It
may damage the switch and should be avoided."

What's that mean?

It probably means that the PWM pulsing circuit is not
properly heat sinked, and will overheat if used more than
intermittently.

Thank you.

Here are some specific questions:

How serious are they?
Or is that like saying "always unplug your TV when not in use"?

What is that warning based on?

Product failures and returns or in house testing.

Is the switch bypassed when fully pressed?

The speed control pulse switching electronics are short
circuited by a contact when the tool is run at full speed.

Do they mean only when under heavy load?

The heavier the load, the sooner the speed control will
overheat.