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NTC Inrush Current Limiter to limit DC motor acceleration?

Started by John Doe February 23, 2012
What would happen if you soldered an NTC Inrush Current Limiter to
the positive terminal of your cordless drill DC motor, in series
with the lead coming from the pulse width modulator (PWM) trigger
speed control? Would that make the drill response laggy? 

Does the resistance change time vary much? What is that attribute
called? 

Thanks. 
"John Doe" <jdoe@usenetlove.invalid> wrote in message 
news:4f46fdc6$0$2190$c3e8da3$c8b7d2e6@news.astraweb.com...
> What would happen if you soldered an NTC Inrush Current Limiter to > the positive terminal of your cordless drill DC motor, in series > with the lead coming from the pulse width modulator (PWM) trigger > speed control? Would that make the drill response laggy? > > Does the resistance change time vary much? What is that attribute > called? >
Resistance change depends on the type of construction and the temperature of the disc. I think about 5:1 is common for inrush limiters. Time lag is a function of the power dissipation in the inrush limiter. That in turn is a function of the current and the resistance of the limiter. The latter decreases as the disc heats up. There are a few good apnotes out there from Epcos and ametherm.