Motor Heating Thermal Image - Santerno DCREG2 Series User Manual

15P0059B3
USER MANUAL
6.6

MOTOR HEATING THERMAL IMAGE

DCREG converter's software is able to detect the motor rise in temperature. A motor heating, i.e. the rise
in temperature with respect to ambient temperature
current I , follows a curve
0
2
   
T ( t ) k I
0
where is the motor thermal time constant and k is a proportional constant with [°C / A
measure.
We may therefore infer that, once temperature has stabilized, the rise in temperature will be proportional
to the current second power, as it is equal to k · I
The figure below shows the heating of a motor supposing it is fed with two different current values (I
I ) which are quantified depending on the reference current represented by parameter C001.
02

T(t)
k I
02 2
·
k C001
2
·
k I
01 2
·
The reference current value programmed in parameter C001 is by default 110% of motor rated current.
Therefore, the rise in temperature is never to exceed the max. allowable temperature, i.e. k•C001
(temperature allowable value when the motor runs regularly with a current equal to C001).
With a current equal to I
For the motor overtemperature protection, the correct setting of the thermal time constant value
programmed in parameter C002 (default value is 300s) is then needed.
102/200
 
t

 


 
1 e
 
 
t*
, alarm A021 will trip in instant t*.
02

T(t) = T(t) – T
amb
2
.
0
I
02
I
01
of a motor supplied with constant
2
] as units of
 C001
 C001
n
DCREG2
DCREG4
and
01
2