TM 5-6675-328-14
NOTE
Whether placed on a bench or hand held, air intake and both exhaust ports must be entirely free of
obstruction. The hand psychrometer samples air to which it is exposed. Care must be taken to use it far
enough away from sources of heat, cold, or moisture. Be sure hand does not contact thermometers during
use.
d.
Place hand psychrometer on flat surface or hold in hand with graduations of thermometer facing up and air
intake pointing to left.
CAUTION
Be sure to turn motor off after each observation since unnecessary usage will greatly shorten life of
batteries.
e.
Turn ON/OFF switch ON and allow wet bulb temperature to stabilize.
f.
If thermometer illumination is desired, turn knob fully right.
NOTE
If wet bulb temperature fails to stabilize within 2..5 minutes after being energized, fan motor is probably
running too slow due to weak batteries.
g.
Turn ON/OFF switch OFF.
h.
Record wet and dry bulb temperatures.
i.
Read psychrometric slide rule as follows:
(1)
Aline wet bulb temperature and dry bulb temperature on slide rule.
EXAMPLE:
WET BULB TEMPERATURE 72
DRY BULB TEMPERATURE 78
% RELATIVE HUMIDITY 74%
(2)
Percentage value of relative humidity is indicated by arrow pointer on sliding center portion of the scale.
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