ABB ACQ550-x1-06A6-2 - Page 125

ACQ550-U1 User’s Manual 125
Parameters
3006 MOT THERM TIME
Sets the motor thermal time constant for the motor temperature
model.
• This is the time required for the motor to reach 63% of the final
temperature with steady load.
• For thermal protection according to UL requirements for NEMA
class motors, use the rule of thumb:
MOTOR THERM TIME equals
35 times t6, where t6 (in seconds) is specified by the motor
manufacturer as the time that the motor can safely operate at six
times its rated current.
• The thermal time for a Class 10 trip curve is 350 s, for a Class
20 trip curve 700 s, and for a Class 30 trip curve 1050 s.
3007 MOT LOAD CURVE
Sets the maximum allowable operating load of the motor.
• With the default value 100%, motor overload protection is functioning
when the constant current exceeds 127% of the parameter 9906
MOTOR NOM CURR value.
• The default overloadability is at the same level as what motor
manufacturers typically allow below 30 °C (86 °F) ambient
temperature and below 1000 m (3300 ft) altitude. When the ambient
temperature exceeds 30 °C (86 °F) or the installation altitude is over
1000 m (3300 ft), decrease the parameter 3007 value according to
the motor manufacturer’s recommendation.
Example: If the constant protection level needs to be 115% of
the motor nominal current, set parameter 3007 value to 91%
(= 115/127·100%).
3008 ZERO SPEED LOAD
Sets the maximum allowable current at zero speed.
• Value is relative to 9906
MOTOR NOM CURR.
3009 BREAK POINT FREQ
Sets the break point frequency for the motor load curve.
Example: Thermal protection trip times when parameters 3006
MOT THERM TIME, 3007 MOT LOAD CURVE and 3008
ZERO SPEED LOAD have default values.
Code Description
Temp. rise
100%
63%
}
P 3006
Motor load
t
t
Frequency
150
50
P 3007
P 3008
P 3009
100 =
127%
Output current relative to
9906
MOTOR NOM CURR
60 s
3.5
I
O
= Output current
I
N
= Nominal motor current
f
O
= Output frequency
f
BRK
= Break point frequency
A = Trip time
3.0
2.5
2.0
1.5
1.0
0.5
0
0 0.2 0.4 0.8 1.0 1.2
90 s
180 s
300 s
600 s
0.6
180 s
A

I
O
/I
N
f
O
/f
BRK