H9 ASD Installation and Operation Manual 13
H9 ASD Characteristics

Over-current Protectio n

Each H9 ASD model was designed for a specified operating power range. The H9 ASD will incur a trip if
the design specification s are ex ce ed ed .
However, the H9 ASD may be operated at 100% of the specified output-current range continuously or at
120% for a limited amount of time as indicated in the section titled Current/Voltage Specifications on pg.
263. Also, the Stall Prevention Level may be adjusted to help with nuisance over-current trips (see F601).
When using the H9 ASD for an application that controls a motor which is rated signifi ca ntly less than the
maximum current rating of the ASD, the over-current limit (Thermal Overload Protection) setting will
have to be changed to match the FLA of the motor. For further information on this paramete r, see Motor
Overload Protection Level 1 on pg. 182.

ASD Capacity

The H9 ASD must not be used with a motor that has a significantly larger capacity, even if the motor is
operated under a small load. An ASD being used in this way will be susceptible to a high-output peak
current which may result in nuisance tripping.
Do not apply a level of input voltage to an ASD that is beyond that which the ASD is rated. The input
voltage may be stepped down when required with the use of a step-down transformer or some other type
of voltage-reduction system.

Using Vector C ontrol

Using Vector Control enables the system to produce very high torque over the entire operating range
even at extremely low speeds . Ve cto r Con trol may be used with or without feedback. However, using
feedback increases the speed accuracy for applications requiring precis e s pee d control.
See F015 on pg. 81 for further information on using Vecto r Co n tro l.