ABB ACS 160 - O Motor Overload Protection

ACS 160 User’s Manual 17
O Motor Overload Protection
ACS 160 provides two ways for motor overload protection in accordance with the National Electric
Code (US): software I
2
t model, which is the default setting, and PTC input. For more information
see Group 30: Fault Functions parameters.
If the motor current (I
out
) from the frequency converter exceeds the motor nominal current (I
N
) for a
prolonged period, the ACS 160 automatically protects the motor against overheating by tripping.
The trip time depends on the extent of the overload (I
out
/ I
N
), the output frequency and motor
nominal frequency (f
nom
), as shown in figure below. Times given apply to a cold start.
Use of motor PTC input
The motor PTC input can only be used in motor mounting. Set parameter 3024 MOT THERM MODE to
3 (
THERMISTOR). When the motor PTC is used the software overload protection for the motor does
not function.
Warning! Use of motor PTC is not allowed in wall mounting because connector X4 is in
main circuit potential.
Requirements for the motor PTC input cable in motor mounting are: wire size 0,5 - 1,5 mm
2
(22...16 AWG), temperature rating 105 °C (221 °F), and voltage rating 500 V
rms
minimum.
I
out
/ I
N
Output frequency
1.5
1.0
0.5
0
0 35 Hz
∞
600 s
300 s180 s
Tr i p t i m e
Motor cable connector
(U2, V2, W2)
Motor PTC
connector
(X4-1, X4-2)
x
4
-
2
x
4
-
1