Specifications - City of Montpelier, Vermont

Title:Montpelier District HeatingCity of Montpelier, VT16480 – MOTOR CONTROLLERSIssue Date:September 28, 2012Page #:8 of 12Continuous current rating 2 amps RMS. Outputs must be trueform C type contacts; open collector outputs are not acceptable.g. Seven (7) programmable preset speeds.h. Two independently adjustable accel and decel ramps. These ramptimes shall be adjustable from 1 to 1800 seconds.i. The VFD shall Ramp or Coast to a stop, as selected by the user.10. The following operating information displays shall be standard on theVFD digital display. The display shall be in complete English words(alphanumeric codes are not acceptable):a. Output Frequencyb. Motor Speed (RPM, % or Engineering units)c. Motor Currentd. Calculated Motor Torquee. Calculated Motor Powerf. DC Bus Voltageg. Output Voltageh. Heatsink Temperaturei. Analog Input Valuesj. Keypad Reference Values11. The VFD shall have the following protection circuits. In the case of aprotective trip, the drive shall stop, and announce the fault condition incomplete words (alphanumeric codes are not acceptable).a. Overcurrent trip 315% instantaneous (225% RMS) of the VFD’svariable torque current rating.b. Overvoltage trip 130% of the VFD’s rated voltage.c. Under voltage trip 65% of the VFD’s rated voltage.d. Over temperature +70C (ACS 501); +85C (ACS 502).e. Ground Fault either running or at start.f. Adaptable Electronic Motor Overload (I2t). The Electronic MotorOverload protection shall protect the motor based on speed, loadcurve, and external fan parameter. Circuits which are not speeddependent are unacceptable. The electronic motor overloadprotection shall be UL Listed for this function.12. Speed Command Input shall be via:a. Keypadb. Two analog inputs, each capable of accepting a 020mA, 420mA,010V, 210V signal. Input shall be isolated from ground, andprogrammable via the keypad for different uses.MOTOR CONTROLLERS 16480 8