Speed/Torque ReferenceThe reference to these controls can either be a single reference or be the sum of various references including relativelyscaled references. For more information on reference handling, see 3.3 Reference Handling.3.2.1 Control PrincipleA frequency converter rectifies AC voltage from mains into DC voltage, after which this DC voltage is converted into ACpower with a variable amplitude and frequency.The motor is supplied with variable voltage/current and frequency, which enables infinitely variable speed control of three-phased, standard AC motors and permanent magnet synchronous motors.130BC514.123-phasepowerinputDC busMotorBrakeresistor88 (-)89 (+)95 PE93 (T/L3)92 (S/L2)91 (R/L1)(R-) 81(R+) 82(PE) 99(U/T1) 96(V/T2) 97(W/T3) 98Illustration 3.1 Control PrincipleThe control terminals provide for wiring feedback, reference, and other input signals to the following:• frequency converter• output of frequency converter status and fault conditions• relays to operate auxiliary equipment• serial communication interfaceControl terminals are programmable for various functions by selecting parameter options described in the main or quickmenus. Most control wiring is customer supplied unless factory ordered. A 24 V DC power supply is also provided for usewith the frequency converter control inputs and outputs. Table 3.3 describes the functions of the control terminals. Many ofthese terminals have multiple functions determined by parameter settings. Some options provide more terminals. See6.2 Mechanical Installation for terminal locations.Table 3.3 describes the functions of the control terminals. Many of these terminals have multiple functions determined byparameter settings. Some options provide more terminals. See 6.2 Mechanical Installation for terminal locations.Product Introduction VLT® AutomationDrive FC 300 Design Guide 90-1200 kW20 MG34S202 - Rev. 2013-08-1933
