Emotron VS10 - Page 146

146 01-6203-01R3, CG Drives & Automation
Details
The operating range of an asynchronous motor consists of the voltage range
①
and the
field weakening range. The field weakening range again is divided into two ranges:
• In the first range
②
, the power can be kept constant without the motor stalling.
• The second field weakening range
③
is characterised by the fact that the maximum
permissible stator current is decreased to prevent the motor from stalling .
Speed/torque curve of the asynchronous motor with two field weakening ranges
The override point (n
2
, M
2
) can be influenced with 0x2B0C (P319.00).
0x2B0C (P319.00) > 0 Hz:
• The maximum current characteristic is shifted to higher field frequencies by the
frequency entered.
• The maximum permissible current and the maximum torque increase in the field
weakening range.
• The risk of motor stalling increases.
0x2B0C (P319.00) < 0 Hz:
• The maximum current characteristic is shifted to lower field frequencies by the
frequency entered.
• The maximum permissible current and the maximum torque are reduced in the field
weakening range.
• The risk of motor stalling is reduced.
Parameter
Name / value range / [default setting]
Info
0x2B0C
(P319.00)
Override field
weakening (Field
weak thold)
-599.0 ... [0.0] ... 599.0 Hz
Offset of the override point for field weakening.
0x2B01:002
(P303.02)
V/f shape data: Base
frequency (V/f shape data:
Base frequency)
Device for 50-Hz mains: 0 ... [50]* ... 1500
Hz Device for 60-Hz mains: 0 ... [60]* ...
1500 Hz
* Default setting depending on the size.
Base voltage and base frequency define the V/f ratio and thus the gradient
of the V/f characteristic.
•
The V/f base voltage is usually set to the rated motor voltage
0x2C01:007 (P320.07).
•
The V/f base frequency is usually set to the rated motor frequency
0x2C01:005 (P320.05).