Beijing Leader & Harvest Electric Technologies Co., Ltd.

A variable frequency drive, which is also called VFD, is used for controlling the frequency of the electrical power supplied to AC electric m.otor, thus controlling the rotational speed of the m.otor. Variable frequency drives are also known as adjustable frequency drives (AFD), variable-speed drives (VSD), AC drives, microdrives or inverter drives. These drives are sometimes also called variable voltage variable frequency (VVVF) drives, for the voltage is varied along with frequency. A variable frequency drive system generally consists of an AC m.otor, a controller and an operator interface.<br><br> A Variable Frequency Drive<br>HARSVERT-A series VFD is a masterpiece of outstanding performance and high reliability, which is widely used for the energy-saving application of the normal m.otors of fans, pumps, compressors, mills, conveyors and lifts. HARSVERT-A series VFD uses new type of IGBT with advanced microcomputer control ...<br><br> VA Variable Frequency Drive<br>Input current harmonic: <3% (comply with standard IEEE519);<br>Input power factor: >0.95(>20% load);<br>Output current harmonic: <2.5%; output DC component: <1% ...<br><br> S Variable Frequency Drive<br>HARSVERT-S series VFD supplies perfect speed-adjustment for the synchronous m.otor and accurate excitation current control for the exciter. It improves the reliability and reduces the cost of the retrofit by using VFD on synchronous m.otor ...<br><br> VS Variable Frequency Drive<br>Vector control for the speed-adjustment of synchronous m.otor;<br>Start ability for starting the synchronous m.otor with load;<br>The response time of dynamic torque: less than 150ms ...<br><br> FVS Variable Frequency Drive<br>PWM rectifier technology. Energy can flow bi-directionally between power grid and the m.otor;<br>Vector control for synchronous m.otor;<br>Strong start up with load in low speed, start torque can reach to 150% rated torque ...<br><br> FVA Variable Frequency Drive<br>Speed sensor-less vector control: speed-adjusting range: 100:1; static speed precision: 0.5%; start torque: 150% rated torque; the response time of dynamic torque: less than 200ms;<br>Speed close loop vector control: speed-adjusting range: 500:1; static speed precision: 0.1% ...