2-206 Torque Performance Modes
would see if it were started across the line. As seen in the diagram below,
the volts/hertz ratio can be changed to provide increased torque
performance when required. The shaping takes place by programming 5
distinct points on the curve:
– Start Boost - Used to create additional torque for breakaway from
zero speed and acceleration of heavy loads at lower speeds
– Run Boost - Used to create additional running torque at low speeds.
The value is typically less than the required acceleration torque. The
drive will lower the boost voltage to this level when running at low
speeds (not accelerating). This reduces excess motor heating that
could be caused if the higher start / accel boost level were used.
– Break Voltage/Frequency - Used to increase the slope of the lower
portion of the Volts / hertz curve, providing additional torque.
– Motor Nameplate Voltage/Frequency - sets the upper portion of the
curve to match the motor design. Marks the beginning of the constant
horsepower region
– Maximum Voltage/Frequency - Slopes that portion of the curve
used above base speed.
Maximum Voltage
Maximum
Frequency
Base Voltage
(Nameplate) Voltage
Base Frequency
(Nameplate)
Break
Frequency
Run Boost
Start/Accel Boost
Break Voltage