Installation manual

Configuration Mode (ConF)
236 S1A28692 03/2010
Motor thermal protection
Function
Thermal protection by calculating the I²t.
Note: The motor thermal state is not saved when the drive is switched off.
• Self-cooled motors: The tripping curves depend on the motor frequency.
• Force-cooled motors: Only the 50 Hz tripping curve needs to be considered, regardless of the motor
frequency.
The following curves represent the trip time in seconds:.
10, 000
1, 000
100
0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6
50 Hz20 Hz10 Hz
1 Hz
3 Hz
5 Hz
Trip time in seconds
Motor current / ItH
CAUTION
RISK OF DAMAGE TO THE MOTOR
External protection against overloads is required under the following circumstances:
• When the product is being switched on again, as there is no memory to record the motor thermal state
• When supplying more than one motor
• When supplying motors with ratings less than 0.2 times the nominal drive current
• When using motor switching
Failure to follow these instructions can result in equipment damage.
Courtesy of Steven Engineering, Inc.-230 Ryan Way, South San Francisco, CA 94080-6370-Main Office: [phone]-Outside Local Area: [phone]-www.stevenengineering.com