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C . Operation <br /> 1 . Accomplish speed control by adjusting both the output voltage and frequency to the <br /> motor. Convert input AC power to a constant voltage DC which is then converted to <br /> adjustable voltage and frequency three-phase AC utilizing pulse width modulation <br /> technology to operate the connected motor at the desired speed . The VFD shall not <br /> induce excess power losses in the motor. The VFD shall not produce voltage impulses <br /> deemed harmful to the motor insulation by the motor Manufacturer . <br /> 2 . Each VFD shall be specifically designed for use with variable torque pumping loads . <br /> Soft-start control circuitry shall limit in -rush current, not to exceed 100 percent of motor <br /> full load current, under all manual and automatic operating conditions . When power <br /> outages occurs , the drive system shall shut down in an orderly manner. Upon restoration <br /> of A.C . power, the motors shall restart sequentially and run at a rate depending upon the <br /> reference requirements , by the sequencing logic controller. <br /> D . Ratings <br /> 1 , Line Voltage : 460 volts, three-phase , (+/-) 10 percent continuous . <br /> 2 . Line Frequency: 48 -62 Hz. <br /> 3 , Ambient Temperature: 0 degrees C to 40 degrees C . <br /> 4 , Altitude : Up to 3300 feet above sea level . <br /> 5 . Maximum Transient Current Variable Torque: 1 .00 continuous, 1 . 10 one minute; <br /> Constant Torque : 1 .00 continuous, 1 . 50 one minute <br /> 6 . Power Factor: Minimum 0 . 95 throughout speed and load range . Power factor correction <br /> by capacitors shall not be acceptable . <br /> E. Performance <br /> 1 . Efficiency. Above 97 percent at 100 percent output frequency (full speed) and full load <br /> as well as above 95 percent at all reduced load and speed conditions between 40 and 100 <br /> percent output frequency. <br /> 2 . VFD Inrush Current: Limited to less than 100 percent of motor full load current. <br /> 3 . Duty Cycle: 6 starts per hour. <br /> 4. Output Frequency Range; 6 hertz to 60 hertz, cogless, with adjustable minimum and <br /> maximum to match the required operating conditions . <br /> 5 . Output fiequency stability (+/-) 1 .0 <br /> percent, continuous <br /> 6. Pulse Width Modulation (PWM) controller carrier frequency regulation shall be designed <br /> for " quiet" motor operation. Induced motor noise when operating at full speed and load <br /> on VFD shall not exceed 5 dBA above the measured motor noise level when operating <br /> 044572017 <br /> 16483 -4 <br />