TOSHIBA
6F9EOlll
7.5 Detection of the Heating Time Constant and Cooling Time Constant
CAUTION:
Detecting the heating time constant and the cooling time
constant requires three
RTDs
in the winding and one RTD
for measuring the ambient temperature to determine the
motor temperature rise.
To enhance the detection accuracy,
care should be taken of the following points:
(1)
The RTD for measuring the ambient temperature
provides a reference temperature for determining the
motor temperature rise, so make sure that you measure
the ambient temperature precisely.
The measuring error of the ambient temperature will
have great effect on the detection accuracy of the
heating time constant and the cooling time constant.
(a)
Do not allow the RTD to be affected by heat
from the motor.
(b)
Keep the RTD free from direct sun rays or
radiant heat.
(c)
Keep the RTD free from influences of cool air
and drafts.
(d)
Keep the RTD free from moisture or high humidity.
(2)
To maintain a required level of accuracy, the heating
time constant and the cooling time constantare
detected under the conditions described later.
The motor must be able to be operated in ways that
meet thm_;tuirements.
The relationship between the motor temperature rise and the heating time
constant is given in equation
(1)
and the relationship between the motor
temperature and the cooling time constant is given in equation (2).
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