Specifications - City of Montpelier, Vermont

Title:Montpelier District HeatingCity of Montpelier, VT16480 – MOTOR CONTROLLERSIssue Date:September 28, 2012Page #:9 of 12c. Analog inputs shall have a programmable filter to remove anyoscillation of the reference signal. The filter shall be adjustablefrom 0.01 to 10 seconds. The analog input should be able to beinverted, so that minimum reference corresponds to maximumspeed, and maximum reference corresponds to minimum speed.The minimum and maximum values (gain and offset) shall beadjustable within the range of 020mA and 010 Volts. The activeanalog input shall have loss of reference protection, if selected.13. Serial Communicationsa. The VFD shall have an RS485 port as standard.b. The VFD shall be able to communicate with PLC’s, DCS’s, andDDC’s. Coordinate requirements with mechanical or controlscontractor.c. Serial communication capabilities shall include, but not be limitedto, runstop control, speed set adjustment, proportional/integral PIcontroller adjustments, current limit, and accel/decel timeadjustments. The drive shall have the capability of allowing theDDC to monitor feedback such as output speed/frequency, current(in amps), % torque, % power, kilowatt hours, relay outputs, anddiagnostic fault information.14. Accessories to be furnished and mounted by the drive manufacturer andcontained in a single NEMA 12 enclosure.a. Terminal strip for connection of external control circuits. Allexternal interlocks and start/stop contacts shall function with handor auto.b. Three phase 3% AC line reactors for harmonic reduction andattenuation of line side voltage transients.c. Three phase RFI line filter to bring drive into compliance withEuropean EMC directives.d. Auxiliary contact representing RUN status.e. Auxiliary contact representing FAIL status.f. Auxiliary contact representing Auto/Manual Mode Status.g. Adequately sized control transformer to furnish power formechanical equipment control devices and internal drivecomponents.h. Manual speed adjusting potentiometer installed on the outsidecover of the VFD.i. VFD shall be provided with two position selector switch to allowoperator to select between local speed control (potentiometer), orremote speed control (PLC or local control panel).MOTOR CONTROLLERS 16480 9