Rockwell Automation 20M LPM15 Liquid-Cooled Adjustable Frequency AC Drive FRN 2.xxx User Manual
Page 113
Application Notes
D-3
[Motor OL Hertz] defines the frequency where motor overload capacity
derate should begin. The motor overload capacity is reduced when
operating below [Motor OL Hertz]. For all settings of [Motor OL Hertz]
other than zero, the overload capacity is reduced to 70% at an output
frequency of zero.
[Motor NP FLA] is multiplied by [Motor OL Factor] to select the rated current
for the motor thermal overload. This can be used to raise or lower the level of
current that will cause the motor thermal overload to trip. The effective overload
factor is a combination of [Motor OL Hertz] and [Motor OL Factor].
Motor Overload Curve
100
125
150
175
200
225
250
Full Load Amps (%)
Tr
ip Time
(Sec)
Cold
Hot
10
100
1000
10000
100000
Changing Overload Hz
0
10
20
30
40
50
60
70
80
90 100
% of Base Speed
Contin
uous Rating
OL Hz = 10
OL Hz = 25
OL Hz = 50
0
20
40
60
80
100
120
Changing Overload Factor
0
10
20
30
40
50
60
70
80
90 100
% of Base Speed
Contin
uous Rating
OL % = 1.20
OL % = 1.00
OL % = 0.80
0
20
40
60
80
100
120
140