Omron VARISPEED G7 -, Instruction Manual

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10
-4
Application Function Precautions
Observe the following precautions when using the application functions.
•
Perform rotational autotuning during trial operation whenever it is possible to separate the motor and
machine. To achieve the characteristics of vector control described in
Table 10.1 , the control must be
adjusted within a range that the machine will not vibrate after rotational autotuning has been performed.
•
With vector control, the motor and Inverter must be connected 1:1. Vector control is not possible when
multiple motors are connected to a single Inverter. Select an Inverter capacity so the rated motor current is
50% to 100% of the rated Inverter current.
•
For estimated speed searching, the motor and Inverter must be connected 1:1. The speed search must be
performed at a frequency of 130 Hz or less and with a motor with the same number of frames as or one
frame less than the Inverter capacity.
•
During high-slip braking, motor loss increases, so use a high-slip braking frequency of 5% ED or less, and
a braking time of 90 seconds or less. Once high-slip braking has started, the motor cannot be restarted until
it has stopped.
•
Feed forward control is a function that improves the proportional gain of the motor speed in relation to the
change in the speed reference. Adjust the response to interference loads using the speed controller (ASR)
constants.
•
The torque limit function will not operate during acceleration or deceleration (during soft start transition)
when using a control mode such as open-loop vector control 1. Even if the motor speed drops due to torque
limiting while set to a fixed speed, the speed will not fall below the minimum frequency and the motor will
not slip into reverse rotation. These conditions also apply to open-loop vector control 2 and other applica-
tion functions.
Precautions When Using Open-loop Vector Control 2
Using open-loop vector control 2 (A1-02=4) gives a higher level of control than conventional open-loop vec-
tor control (A1-02=2). When using open-loop vector control 2, pay attention to the points listed below. For a
comparison with other control modes, refer to
Table 10.1 Overview and Features of Control Modes .
General Precautions
•
The maximum possible setting for the maximum output frequency (E1-04) is 60 Hz.
•
Be sure to perform autotuning. Refer to the precautions given under Autotuning in Chapter 4 Trial Opera-
tion .
Precaution on Regeneration
With speed control, in the low speed range (approx. 6 Hz max.), the speed increases for large regenerative
loads, and it may not be possible to maintain speed accuracy. Examples are given below for forward rota-
tion at frequencies of 0.3, 1, 3, 6, and 60 Hz.