Parker AC890PX Series, Инженерный справочник

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D-64
A p p e n d i x D : P r o g r a m m i n g
AC890PX AC Drive
INVERSE TIME PMAC
SETUP::MOTOR CONTROL::INVERSE TIME PMAC
Designed for PMAC control mode.
The purpose of the inverse time is to automatically reduce the drive current limit in response to prolonged overload conditions (drive protection).
For Frames B, C & D:
Under normal conditions, the drive current limit is set to the minimum value between:
- 200% of the permanent Drive current (STACK CURRENT parameter of the FEEDBACKS Function Block)
- MAX CURRENT parameter of the MOTOR PMAC 1 Function Block
If the Drive speed becomes lower than 2.5 (electrical) Hz, the DELAY time is automatically reduced to 25% of its value.
As the drive current exceeds the AIMING POINT level, the excess current is integrated. Motor current is allowed to flow at the minimum
value between 200% of permanent drive current and MAX CURRENT (refer to the MOTOR PMAC 1 function block) for a period defined
by the DELAY parameter. At this point the inverse time current limit is ramped down from the MAX CURRENT. The rate at which the
inverse time current limit is ramped to the AIMING POINT is defined by DOWN TIME.
Once the overload condition is removed, the inverse time current limit level is ramped back toward the minimum value between 200% of
permanent drive current and MAX CURRENT at a rate determined by the UP TIME.
For Other Frame Sizes:
Under Normal conditions , the drive limit is set to the minimum value between:
- 150% of the permanent drive current,
- MAX CURRENT parameter of the MOTOR PMAC 1 Function block for a delay value of 60s.
In Quadratic Torque mode, the allowed overload is reduced to 110% for 60s before inverse time current limit action occurs.