A remote-mounted variable frequency drive connects via power wiring to a local motor disconnect switch, which feeds the motor load. Interconnecting wiring and programming interlock the variable frequency drive and disconnect switch so that the drive cannot energize load conductors when the switch is open. The disconnect switch is equipped with normally open and normally closed auxiliary contacts that change state when the switch operates. A required safety label instructs operators to shut down the variable frequency drive before opening the disconnect. When the variable frequency drive is located more than one hundred feet from the motor, a five percent reactor is installed on the load side of the drive.
VFD REMOTE MOUNTED VFD (NOTE 4) NOTE 3 LOCAL MOTOR DISCONNECT SWITCH (NOTE 2) NOTE 1 POWER WIRING NOTES: 1. PROVIDE INTERCONNECTING WIRING AND VFD PROGRAMMING AS REQUIRED TO INTERLOCK VFD AND DISCONNECT SWITCH SUCH THAT VFD CANNOT ENERGIZE LOAD CONDUCTORS WHEN LOCAL MOTOR DISCONNECT SWITCH IS IN THE OPEN POSITION. 2. PROVIDE DISCONNECT SWITCH WITH NO/NC AUXILLIARY CONTACTS WHICH CHANGE STATE WHEN SWITCH IS OPEN/CLOSED. 3. PROVIDE LABEL WHICH READS THE FOLLOWING: "MOTOR MUST BE PROPERLY SHUT DOWN FOR THE VARIABLE FREQUENCY DRIVE BEFORE OPENING THIS DISCONNECT. DO NOT OPEN THIS DISCONNECT WHILR THE MOTOR IS RUNNING." 4. WHERE VFD IS LOCATED MORE THAN 100' FROM MOTOR, PROVIDE 5% REACTOR ON THE LOAD SIDE OF THE VFD.
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