Can moters be run slower with less voltage (brush types)

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I heard power tools run on long cords go bad sooner.  I assume because
of the voltage drop the motor runs slower.   I am thinking that the
voltage drop is not a direct factor but slower speeds means less
airflow since they all have a fan on the shaft (except pass through
vacuums unless heavy duty.  I remember in the seventies sears had a
vacuum that had two speeds.  But I think it was controlled by the entry
point of the wire in motor, not a device that is like a dimmer made for
brush motors.  I saw one on a centrifuge and after market for routers.


I am asking if lack of air flow from lower speeds due to voltage drops
damage power tools (skilsaw and such)


Re: Can moters be run slower with less voltage (brush types)


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I wouldn't put much stock in it, but shorter, heavier cords are a good idea.
I'd be more concerned about low voltage at the outlets. Maybe your tools are
just cheap?








Re: Can moters be run slower with less voltage (brush types)

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I only hear about power tools like skill saws can be damaged.  Never
had a tool go bad.  I thought these motors can run at any speed if cool.


Re: Can moters be run slower with less voltage (brush types)

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I forgot to say that cheap tools do break quick, stuff from China, I am
not blaming them though, they deliver what the market will take.

What I thinks I am really asking is a long cord voltage drop similar to
after-market devices that slow down motors like a router?


Re: Can moters be run slower with less voltage (brush types)

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Similar, you're limiting the current though rather than effectively
using PWM so you'll get less torque with voltage drop than with a speed
controller, the motor shouldn't heat up more than usual though.

Induction motors on the other hand will overheat if the voltage drops.
They're constant power devices and lower voltage will cause higher
current to be drawn to compensate, higher current = more heat.

Re: Can moters be run slower with less voltage (brush types)

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Thankyou: it is popular among carpenters but they can continue thinking
that and get the large cords. I do not want to explain it unless asked.


Re: Can moters be run slower with less voltage (brush types)

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Dont believe everything. The only motors so affected are induction
motors, which are at times found in stationary tools but not hand
helds.

Reducing V reduces both power diss and airflow, and temp stays roughly
constant over a wide speed range.


NT


Re: Can moters be run slower with less voltage (brush types)

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Thankyou: it is popular among carpenters but they can continue thinking
that and get the large cords.


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