Siemens LMV3 series, Технические инструкции

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Technical Instructions LMV Series
Document No. LV3-1000
Section 5
Page 22 SCC Inc.
7.
Set the VSD blower speed monitoring bands to values that are safe for the application. See
complete explanation of these bands detailed earlier in this section
a. VFDs with three phase blowers are typically more accurate from a speed control standpoint,
especially if a vector type of VFD is used. For a vector type VFD driving a three phase
blower, the neutral band (parameter 662) and the near band (parameter 663) can typically
be left at their lowest values of 662 = 0.5% and 663 = 2%. If the application in question does
not require fuel-to-air ratio control that is this precise, the neutral band and the near band
can be increased. Maximum values of 662 = 3.5% and 663 = 5.5% are seldom needed if a
VFD and three phase blower are functioning properly.
b. PWM blowers are somewhat less accurate from a speed control standpoint, but still have
adequate accuracy for most applications. When using a PWM blower, the neutral band
(parameter 662) and the near band (parameter 663) are typically set at values of 662 = 2.5%
and 663 = 4.5%, assuming that it is safe to have this amount of fuel-to-air ratio control
variance in the application. Maximum values of 662 = 3.5% and 663 = 5.5% are occasionally
needed for PWM blowers if they are not correctly programmed for the application.
8. Set the pre-purge position of the air actuator, which is typically the same as the high fire position of
the air actuator. This is set with either parameter 502, index 01 for fuel 0, or parameter 505, index
01 for fuel 1.
9. Ensure that the safety loop is closed, and that the main power is turned on to the VSD. Also ensure
that the burner switch is off. Start the standardization procedure by setting parameter 641 to 1.
See complete explanation of the standardization procedure earlier in this section.
10. After the standardization is completed successfully, parameter 641 will return to 0 and “OFF UPR”
will be displayed on the AZL. If a value appears other than 0, see Error Code 82 in Section 6 of this
manual for the cause of the error.
11. If desired, the standardized speed that was recorded during the standardization procedure can be
viewed under parameter 642, index 01 and index 02.
12. After the standardization has been completed successfully, the VSD is now ready to run and the fuel-
to-air ratio curves can be set.