Siemens LMV3 series, Технические инструкции

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LMV Series Technical Instructions
Document No. LV3-1000
SCC Inc.
Page 21 Section 5
2.
Determine if separate ramping of VSD and air damper is necessary when driving from pre-purge to
ignition. If separate ramping is used, the air damper stays at pre-purge position while the VSD
ramps down to ignition position. This has a braking effect on the blower, and is very useful for PWM
blowers and VFD without braking resistors. The disadvantage is a slightly longer start up time.
RECOMMENDATION: If a PWM blower or a VFD without a braking resistor is being used, set
parameter 529 to 2, which utilizes the separate ramping and also allows for 50% more speed
tolerance before the main fuel valves are open.
3. Set parameter 542 to 1, which activates the VSD control functionality in the LMV3. This is necessary
for any type of VSD that will be used with the LMV3.
4. Determine the type of speed feedback (tachometer) that will be used with the LMV3. When the
VSD is part of a non-pneumatic parallel positioning burner control, speed feedback is required.
a.
For VFD with three phase blowers that utilize a speed wheel kit for speed feedback, set
parameter 643 to 0, which indicates an asymmetric pulse pattern that matches the speed
wheel kit. This speed wheel kit also produces 3 pulses per revolution, so ensure that
parameter 644 is set to 3.
b. For PWM blowers that utilize the internal Hall Effect sensors, set parameter 643 to 1, which
indicates an equally spaced symmetric pulse pattern. A symmetric pulse pattern is used by
most PWM blower manufacturers. The number of pulses per revolution varies by model
and manufacturer, but is typically 2 or 3 pulses per revolution. Determine the number of
pulses per revolution, and set parameter 644 for this number. Parameter 644 can be set for
1 to 6 pulses per revolution.
5.
Determine if it is permissible for the blower wheel to coast from post purge speed down to home
position speed, which is typically 0% VSD. If the blower wheel is permitted to coast, the LMV3 will
take slightly longer to get to home position which may be a concern if the burner needs to come
back on immediately.
RECOMMENDATION: If a PWM blower or a VFD without a braking resistor is being used, set
parameter 653 to 0, allowing the VSD to coast down after post purge. Setting parameter 653 to 1
will ramp the VSD to home position more quickly, but may also cause VSD issues if braking is not
used.
6. Set parameter 661 to activate or deactivate the LMV3 internal speed control.
a. For VFDs with three phase blowers, parameter 661 is typically set to 1, which keeps the
LMV3 internal speed control activated.
b. For PWM blowers, especially those utilizing a properly tuned onboard speed control,
parameter 661 is typically set to 0, which turns off the speed control inside the LMV3.