Chapter 6 – Parameters
ACH 500 Programming Manual 6-33
4 MOTOR THERM TIME
The time period within which the motor temperature reaches 63 percent of the
final temperature rise. As a rule of thumb, Motor Thermal Time equals 35
times t6 (t6 in seconds is the time that the motor can safely operate at six
times its rated current, given by the motor manufacturer). Table 6-16 shows
some motor thermal times measured by ABB. The default value is set to 700s,
which is the value for a Class 20 trip curve. This has been tested and is UL
Listed as motor overload protection. The time for a Class 10 trip curve is 350s
and for a Class 30 trip curve is 1050s.
Table 6-16 Motor Thermal Times
P
N
[HP]
Number of Poles
2 4 6
t
[s]
t
[s]
t
[s]
3 660 1020 1440
5 780 1140 1740
7.5 900 1260 1760
10 970 1380 1860
15 1140 1560 2040
20 1200 1740 2340
25 1260 1860 2340
30 1380 2040 2760
40 1680 2220 2940
50 1860 2460 3180
60 2040 2640 3420
75 2220 2820 3660
100 2400 3120 3960
125 2640 3300 4320
150 2820 3600 4680
200 3120 3960 5100
250 3420 4320 5700
300 3780 4740 6420
350 3780 4740 6420
400 3780 4740 6420
To Next Page
Loading...
