Emerson FXMP25 User Manual page 35

If Pr 29 and Pr 30 have their default values of 50 and 75, the characteristic becomes
one line and there will be a linear relationship between the field controller estimate of
flux and the field current. If Pr 29 and Pr 30 are increased above 50 and 75 the field
controller estimate of flux can included the effect of the non linearity. It is unlikely that
information will be available to set-up these parameters, and so the values are
determined during the rotating autotune test (in Mentor MP mode only). To set these
values in stand alone mode use the following procedure:
• Ensure that Pr 29, Pr 30, Pr 68 and Pr 74 are set to their default values of 50 %,
75 %, 100 % and 100 % respectively.
• Set the speed demand to 1/4 of Base speed and run the machine up to speed and
check the speed of the machine using a hand held device.
• If the machine speed is lower than 1/4 of Base speed (which is normally the case)
adjust the Field compensation factor (Pr 74) down until the correct machine speed
is reached. If the machine speed is higher than
the motor nameplate field current is low), adjust the Rated field current (Pr 70) up
until the correct machine speed is reached.
• Set Pr 68 Maximum flux to 75 % and measure the actual speed of the machine
(speed 75)
• Set Pr 68 Maximum flux to 50 % and measure the actual speed of the machine
(speed 50).
• Stop the machine and set Pr 68 Maximum flux back to 100 %.
• Set Pr 29 Motor saturation breakpoint 1 = 50 x set speed / actual speed (Speed 50)
• Set Pr 30 Motor saturation breakpoint 2 = 75 x set speed / actual speed (speed 75).
• Press mode to save parameters.
FXMP25 User Guide
Issue Number: 3
flux (%)
100%
Pr 5.30
Pr 5.29
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Linear characteristic
(i.e. no saturation)
50 75 100 Field
current (%)
1
of Base speed (only possible if
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4
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