120
Thermal phase overload protection
(THOL)
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&XUUHQW
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The parameters for the thermal phase overload protection function are set via the local
HMI or PST (Parameter Setting Tool). Refer to the Technical reference manual for set-
ting parameters and path in local HMI.
To make the correct settings, the following data are required for the protected object:
•
Final temperature rise after continuos load with specified load current
•
Max. permissible continuous temperature and thermal time constant
τ
of the object
•
Max. ambient temperature
•
Max. temperature rise due to radiant power from the sun - if significant
The time constant can be found if a curve is available which shows the temperature rise
as a function of time for a given load current. At load current Iload and final temperature
rise T
fin
the following is valid:
If different values of
τ
are calculated from the curve, select the lowest value of
τ
to ob-
tain the best protection.
The time to function is calculated from the formula:
(Equation 57)
7LPH
1 x
τ
2 x
τ
3 x
τ
4 x
τ
5 x
τ
7HPSHUDWXUH ULVH LQ
RI7
ILQ
:
63
86
95
98
99
Where:
p
is Ip/I
base
Ip
is continuous load current before the current is increased to I
T
amb
is ambient temperature. (T
amb
is 20° C as a fixed value if temperature compensa-
tion is not used)
t
τ
In
I
I
base
------------
2
p
2
–
I
I
base
------------
2
T
trip
T
amb
–
T
base
-----------------------------
–
--------------------------------------------------------
⋅
=
Summary of Contents for REO 517
Page 10: ... RQWHQWV ...
Page 16: ...6 Introduction to the application manual KDSWHU QWURGXFWLRQ ...
Page 64: ...54 Blocking of signals during test KDSWHU RPPRQ IXQFWLRQV ...
Page 88: ...78 Scheme communication logic ZCOM KDSWHU LQH LPSHGDQFH ...
Page 146: ...136 Unbalance protection for capacitor banks TOCC KDSWHU XUUHQW ...
Page 166: ...156 Dead line detection DLD KDSWHU 3RZHU V VWHP VXSHUYLVLRQ ...
Page 378: ...368 Monitoring of DC analog measurements KDSWHU 0RQLWRULQJ ...
Page 384: ...374 Pulse counter logic PC KDSWHU 0HWHULQJ ...
Page 412: ...402 Serial communication modules SCM KDSWHU DWD FRPPXQLFDWLRQ ...
Page 440: ...430 LED indication module KDSWHU DUGZDUH PRGXOHV ...