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  1. SolDirJoe

    photon energy conversion

    Depends what you want to do I guess, but if you need only to detect the presence and level of IR striking a given surface, then a crude [powered] convertor would be to couple a basic photo-transister to a basic transistor amplifier feeding an ordinary flashlamp bulb. The higher the level of IR...
  2. SolDirJoe

    DC motor vs. AC motor Efficiency.

    radarray is right. Power Factor is the key unless you are always operating at 80% or above base speed. IGBT transistors and the rectifier volt drops AC Invertor drives], are lower than the voltage drop across hi-power thyristors [dc drive convertors] so heat is not quite as high. However, the...
  3. SolDirJoe

    VFD versus Magna Drive

    No question an AC Invertor is best. Mag couplings do the job and are 'simpler' to figure out. However, they are inefficient, especially if idling and at low output speeds. Given the power in this case you can calculate the time it would take to recoup capital expenditure if you have realistic...
  4. SolDirJoe

    MOTOR OR GENERATOR??

    It would be a 'messy' way to do it, BU:- If the AC motor is electricaly connected to an AC invertor fed from the truck 24 battery system, and mechanically coupled to the truck engine or transmission in some way. Then the fridge compressors could be driven by DC Motors. As the AC motor is...
  5. SolDirJoe

    Rate of Heat Lost

    Thanks guys, All very helpful stuff. To answer few queries :- Cu is 99% pure. The wire is electricaly heated as it passes through a nitrogen atmosphere [to prevent oxidation], before passing into the coolant chamber. Transfer from one chamber to the other is via a grouve in a rotating brass...
  6. SolDirJoe

    500hp motor - monitoring of temperature for windings and bearings

    For this type of application, differential temperature measurement can be useful. [NB. Absolute overtemp alarms, if set to a point which gives adequate warning or alarm trip, are subject to false alarms due to excessive change in ambient temp sudden increase in demand, or load duty cycle]...
  7. SolDirJoe

    500hp motor - monitoring of temperature for windings and bearings

    Are these motors used on dynamometers ? If so, inbalance of the coupling and lack of lubrication at critical speed could lead to destructive failure in seconds. Are the motors AC or DC machines and what is the voltage ? Are they variable speed ? If so how is speed varied [eg DC Thyristor...
  8. SolDirJoe

    Rate of Heat Lost

    The coolant is water constantly recirculating from a reservoir into a tank at a high flow rate through which the 0.50mm diameter wire is travelling at 30 m/sec. The "tank" dimensions are 600mm long : 350mm wide : 150mm deep. The temperature of the wire on entry is 400 deg C. Coolant...
  9. SolDirJoe

    Rate of Heat Lost

    Can any one offer best formula [with definitions and units] to calculate the heats lost by hot copper wire as it transits through a coolant at high speed. ? ie. Wire T 400 deg C : Coolant 15 deg C : speed 30 metres per second.

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