Vfd Bypass; Introduction - Siemens LMV5 Series Technical Instructions

LMV Series

VFD Bypass

Introduction

When using an LMV52 with a variable frequency drive (VFD), it may be beneficial to bypass the
VFD and run the motor at full speed. There are typically two reasons for doing this:
• On a single fuel system, it is desired to have the ability to run without the VFD, typically
in the event of a VFD malfunction.
• On a dual fuel system, it is desired to use the VFD with one fuel (typically gas) but not
the other fuel (typically oil).
The following pages provide the information to apply a VFD bypass on either a single or dual
fuel system. For the single fuel system, the fuel is assumed to be gas. For the dual fuel system,
it will be assumed that the main fuel is gas and the secondary fuel is oil.
SCC Inc. Page 37
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Technical Instructions
Document No. LV5-8000
Appendix A