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Factory Automation


Factory Automation

FAQAbout Products

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  • No : 22086
  • Release Date : 2018/08/22 16:30
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Angular velocity change control

How can I change the angular velocity during a single rotation of a motor? For example, I want to set the angular velocity to a certain rpm value from 0 deg to 20 deg and to another from 20 deg to 180 deg.
For what ranges of rotations per minute and angular velocity can I implement such control?
Planned motor: General-purpose three-phase motor 18.5 kW
How does the number of poles influence this control?
1. When using a general-purpose inverter (A500) with a general-purpose motor
2. When using a vector inverter and a vector control dedicated motor
Category : 


The inverter itself does not have a function to detect the rotation angle and change the velocity accordingly. Therefore, to implement required control, it is necessary to externally detect the motor shaft angle and switch the speed setting signal to the inverter accordingly.

The control range depends on the time required after detection of the motor shaft angle until the inverter responds to it.
Therefore, to determine concrete control angle, the time required for motor shaft angle detection must be known.
If the inverter takes approximately 100 ms to respond after detecting the motor shaft angle, the error for 60 rpm (2 Hz for the 4-pole motor and 1 Hz for the 2-pole motor) is approximately 40 degrees and the error for 30 rpm (2 Hz for the 4-pole motor and 1 Hz for the 2-pole motor) is approximately 20 degrees. Since this operation depends on how much low speed operation can be controlled (how large the speed control range is), refer to the following:

Speed control range
FR-A500: Low speed 0.5 Hz or higher (15 rpm with 4-pole motor and 30 rpm at 2-pole motor), FR-V200E: Low speed 1 rpm or higher
Product Name
Inverter, magnet motor drive
Product Category
FR-A500, FR-V200

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