Re: NTC 5D-9 Thermistor?



Bob Shuman wrote:

> More importantly, if I wanted to beef up this part to prevent this
> from happening again, what generic parameters should I be looking for
> in a thermistor at the local RS store? The 5 ohms and .18 ohm are a
> good place to start, but I did not see any type of current limit or
> power rating (assuming the .18 ohms) for the device.

If it is a 600W non-PFC power supply we might assume at 80% efficiency
the input power to be somewhere around 750W.

750/120 = 6.25A (sound familiar) - full power operation.

Per Ohm's Law: 5 ohm starting resistance = 31W if starting inrush is
100% of full power load (not likely).
..18 ohm ending resistance = 1.125W at full power.

Note that the inrush current limit for the 5D-9 is only 3A, so either
you don't have a 600W supply or (most probably) the max starting surge
is calculated at 50% of the full power load or perhaps as you stated the
device is underrated. You decide.


.



Relevant Pages

  • Re: A Comparison
    ... >>> Krell to deliver twice the power in half the load, ... the current doesn't double with half the load. ... >> changing the load from 8 to 4 ohms. ...
    (rec.audio.opinion)
  • Integrated amp for Dynaudio BM15 passives?
    ... amplifier, though they rate the dynamic power at 8/6/4/2 ohms, and DIN ... IEC power (8 ohms, 1 khz 0.01 THD ... IEC Short term powerhandling>1000W ...
    (rec.audio.pro)
  • Re: A Comparison
    ... >>> Krell to deliver twice the power in half the load, ... the current doesn't double with half the load. ... >> changing the load from 8 to 4 ohms. ...
    (rec.audio.opinion)
  • Re: If you must go with tubes.............
    ... Power Output Ratings:Less than 0.25% total harmonic distortion at any ... power level up to 200 watts continuous average power per channel into 8 ... ohms) at any frequency between 20 Hz and 20 KHz with both channels ... Power at Clipping, single channel, 2500 Hz, less than 1% distortion: ...
    (rec.audio.tubes)
  • Re: A Comparison
    ... >> Input Impedance = 100 K Ohms ... > ability of the Krell to deliver twice the power (meaning ... an ideal amp and puts out twice the power into 4 ohms. ...
    (rec.audio.opinion)