M-Maxâ„¢ Series Adjustable Frequency Drive - Eaton Corporation
M-Maxâ„¢ Series Adjustable Frequency Drive - Eaton Corporation
M-Maxâ„¢ Series Adjustable Frequency Drive - Eaton Corporation
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V/Hz-Characteristic Curve (P11)<br />
The M-Max series frequency inverters operate with a<br />
sinusoidal pulse width modulation (PWM) in the inverter. The<br />
IGBTs are actuated by two V/f-based control procedures that<br />
you can select in parameter P11.8.<br />
P11.8 = 0:<br />
● <strong>Frequency</strong> control (Hz)<br />
● Parallel connection of several motors<br />
● Large power difference (PFU >> PMotor )<br />
● Switching in the output<br />
P11.8 = 1:<br />
● Speed control (RPM, min –1 ) with slip compensation<br />
● Single operation (only one motor), maximum one power<br />
rating smaller<br />
● High torque (requirement: exact motor data for the motor<br />
calculation model)<br />
V/Hz-Characteristic Curve<br />
PNU ID<br />
Access<br />
RUN Value/Range Description<br />
Parameters<br />
The V/f characteristic (voltage/frequency characteristic)<br />
represents a control procedure of the frequency inverter in<br />
which the motor voltage is controlled in a specific ratio to the<br />
frequency. If the voltage/frequency ratio is constant (linear<br />
characteristic), the magnetizing flux and the torque behavior<br />
of the connected motor is virtually constant.<br />
In the standard application, the benchmark values for the<br />
V/Hz-characteristic curve correspond with the rated<br />
operational data of the connected motor (see the motor<br />
ratings plate):<br />
● Cut-off frequency P11.2 = Rated motor frequency<br />
P7.6 = Maximum frequency P6.4<br />
● Output voltage P11.3 = Nominal motor voltage P7.5<br />
The rating data of the V/Hz-characteristic curve is assigned<br />
automatically and corresponds with the values of parameter<br />
P7.5 (nominal motor voltage) and P7.6 (rated motor frequency).<br />
If you require other values for the V/Hz-characteristic curve,<br />
you must first set parameters P7.5 and P7.6, before you<br />
change the parameters of the V/Hz-characteristic curve<br />
shown here.<br />
P11.1 108 X — V/Hz characteristic curve 0<br />
0 Linear<br />
The output voltage changes linearly with the output frequency;<br />
from zero to voltage P11.3 with the cut-off frequency P11.2<br />
By defining a minimum frequency (P6.3), a voltage<br />
corresponding with one of the linear characteristic curves is<br />
output<br />
The V/Hz ratio running linearly between zero and the cut-off<br />
frequency remains constant<br />
With parameter P11.6, the voltage value can be raised by<br />
percentages in a linear V/Hz-ratio over the entire manipulating<br />
range<br />
1 Squared<br />
The output voltage changes quadratically with the output<br />
frequency; from zero to voltage P11.3 with the cut-off<br />
frequency P11.2<br />
By defining a minimum frequency P6.3, a voltage corresponding<br />
with one of the quadratic characteristic curves is output. The<br />
V/Hz ratio running quadratically between zero and the cut-off<br />
frequency remains constant<br />
With parameter P11.6, the voltage value can be raised as a<br />
percentage by a quadratic V/Hz ratio over the entire<br />
manipulating range<br />
2 Configurable<br />
In connection with parameters P11.4, P11.5 and P11.6, the V/Hz<br />
ratio and therefore the parameters for characteristic curve<br />
progress can be defined as required<br />
Factory Setting<br />
(P1.3)<br />
M-Max <strong>Series</strong> <strong>Adjustable</strong> <strong>Frequency</strong> <strong>Drive</strong> MN04020003E—April 2011 www.eaton.com 105