一、是一种集软启动、软停车、轻载节能和多功能保护于一体的装备。实现在整个启动过程中无冲击而平滑的启动电机，而且可根据电动机负载的特性来调节启动过程中的各种参数，如限流值、启动时间等。
二、（Variable-frequency Drive，VFD）是应用与微电子技尸通过改变电机工作电源频率方式来控制的电力控制设备。
三、和软启动的区别
1、频率方面： 的输出频率固定为电源频率，频率不可调；是输出频率可调。
2、电压方面： 通过控制（或其他电力电子元件）导通角来控制输出电压，其输出电压由0V慢慢升到；变频器的电压是可调的。
3、电机速度方面：
软启动器不可调节电机速度；变频器可以调节电机在rh速度运行。
CPSS18/30-500L
PSS30/52-500L
PSS37/64-500L
PSS44/76-500L
PSS50/85-500L
PSS60/105-500L
PSS72/124-500L
PSS85/147-500L
PSS105/181-500L
PSS142/245-500L
PSS175/300-500L
PSS250/430-500L
PSS300/515-500L
PSTEK
PSTM-2
PSTHM-26/16
PSTHM-44/16
PSTHM-56/16
PSTHM-95/16
PSTP-280/16
PSTP-280/18
PSTP-370/16
PSTP-370/18
PSTP-540/16
PSTP-540/18
PSTP-600/16
PSTP-760/18
PSTP-990/16
PSTHM-132/16
PSTHM-162/16
PSTHM-200/16
PSTHM-312/16
PSTHM-501/16
PST 30-600-70
PST 30-690-70
PST 37-600-70
PST 37-690-70
PST 44-600-70
PST 44-690-70
PST 50-600-70
PST 50-690-70
PST 60-600-70
PST 60-690-70
PST 72-600-70
PST 72-690-70
PST 85-600-70
PST 85-690-70
PST 105-600-70
PST 105-690-70
PST 142-600-70
PST 142-690-70
PST 175-600-70
PST 210-600-70
PST 210-690-70
PST 250-600-70
PST 250-690-70
PST 300-600-70
PST 300-690-70
PST 30-600-70T
PST 30-690-70T
PST 37-600-70T
PST 37-690-70T
PST 44-600-70T
PST 44-690-70T
PST 50-600-70T
PST 50-690-70T
PST 60-600-70T
PST 60-690-70T
PST 72-600-70T
PST 72-690-70T
PST 85-600-70T
PST 85-690-70T
PST 105-600-70T
PST 105-690-70T
PST 142-600-70T
PST 142-690-70T
PST 175-600-70T
PST 175-690-70T
PST 210-600-70T
PST 210-690-70T
PST 250-600-70T
PST 250-690-70T
PST 300-600-70T
PST 300-690-70T
PSEEK
PSEHMI-1
PSEHMI-2
PSEHMI-3
PSE Demo box
PSE18-600-70
PSE25-600-70
PSE30-600-70
PSE37-600-70
PSE45-600-70
PSE60-600-70
PSE72-600-70
PSE85-600-70
PSE105-600-70
PSE105-600-70
PSE170-600-70
PSE210-600-70
PSE250-600-70
PSE300-600-70
PSE370-600-70
PSR3-600-11
PSR3-600-70
PSR6-600-11
PSR6-600-70
PSR9-600-11
PSR9-600-70
PSR12-600-11
PSR12-600-70
PSR16-600-11
PSR16-600-70
PSR25-600-11
PSR30-600-11
PSR30-600-70
PSR37-600-11
PSR37-600-70
PSR45-600-11
PSR45-600-70
PSR60-600-11
PSR60-600-70
PSR72-600-11
PSR72-600-70
PSR85-600-11
PSR85-600-70
PSRC3-600-70
PSRC6-600-70
PSRC9-600-70
PSR105-600-11
PSR105-600-70
PSRC12-600-70
PSRC16-600-70
PSRC25-600-70
PSRC30-600-70
PSRC37-600-70
PSRC45-600-70
PSRC60-600-70
PSRC72-600-70
PSRC85-600-70
PSR-Fan(3-45)
PSRC105-600-70
PSR-Fan(60-105)
PSTB 370-600-70
PSTB 370-690-70
PSTB 470-600-70
PSTB 470-690-70
PSTB 570-600-70
PSTB 570-690-70
PSTB 720-600-70
PSTB 720-690-70
PSTB 840-600-70
PSTB 840-690-70
PSTB 1050-600-70
PSTB 1050-690-70
PSTB 370-600-70T
PSTB 370-690-70T
PSTB 470-600-70T
PSTB 470-690-70T
PSTB 570-600-70T
PSTB 570-690-70T
PSTB 720-600-70T
PSTB 720-690-70T
PSTB 840-600-70T
PSTB 840-690-70T
PSTB 1050-600-70T
PSTB 1050-690-70T
PSTX30-600-70
PSTX30-690-70
PSTX37-600-70
PSTX37-690-70
PSTX45-600-70
PSTX45-690-70
PSTX60-600-70
PSTX60-690-70
PSTX72-600-70
PSTX72-690-70
PSTX85-600-70
PSTX85-690-70
PSTX105-600-70
PSTX105-690-70
PSTX142-600-70
PSTX142-690-70
PSTX170-600-70
PSTX170-690-70
PSTX210-600-70
PSTX210-690-70
PSTX250-600-70
PSTX250-690-70
PSTX300-600-70
PSTX300-690-70
PSTX370-600-70
PSTX370-690-70
PSTX470-600-70
PSTX470-690-70
PSTX570-600-70
PSTX570-690-70
PSTX720-600-70
PSTX720-690-70
PSTX840-600-70
PSTX840-690-70
PSTX1050-600-70
PSTX1050-690-70
PSTX1250-600-70
PSTX1250-690-70
