Originally Posted by
RR_NDB
Hi,
How many watts maximum? 115V?
Just increase the power would shorten the "unreliable indications"?
What kind of factor could limit the maximum power to be applied?
The mentioned power "modulator" reads TAT?
For certain conditions why not to apply "extreme power"? What kind of limitation to do that?
270 W
The A300 FCOM mentions 28VDC and 320W, but the actual power deliverable will not be constant. The probe heaters are made out of resistance wire, the actual resistance changes with temperature, so monitoring the current gives an indication of the heater coil temperature. In other applications such as process industries handling flammable materials self limiting heat tracing tapes are used exploiting this effect.
For what power - consider a bench soldering iron - 12W can be used without any control to limit tip to about 200degC. 60W irons need temperature control - can only use higher power when soldering big things. Instant heat guns 100W will heat tip to red-heat in a few seconds. I'm sure you don't want the pitot tube more than 60degC on the ground, but its very important that you can check the heating - design case for heating and drain holes will be take-off clinb in bad weather.