Siemens LMV3 series - VSD Blower Speed Response During Deceleration

LMV Series Technical Instructions
Document No. LV3-1000
SCC Inc. Page 19 Section 5
For the standardized speed and the setting of parameter 662 shown above, the blower can deviate from
the standardized speed baseline by +/- 2.5% of the standardized speed (+/- 89 RPM) at anywhere from
10% to 100% VSD without causing the LMV3 to pause modulation. If the standardized speed was 6500
RPM (common for PWM blowers) and parameter 662 was set to 3.5%, then the blower speed could
deviate up to +/- 227 RPM without causing the LMV3 to pause modulation.
Figure 5-7 below shows a VSD blower ramping down (decelerating) during operation. The exact same
principles that applied to the VSD blower ramping up apply to the ramp down; however, inertia effects
and a lack of braking typically cause a more non-linear response when ramping down.
Figure 5-7: VSD Blower Speed Response during Deceleration
NOTE: Absolute minimum speed for VSD Blowers controlled by the LMV3 is 10% of the standardized
speed.