Soft Start and VFD with bypass

If desperate bypass is needed most systems have a line contactor before the VFD,just disconnect the motor leads from the outgoing VFD side and connect direct to the line contactor side feeding the VFD. Motor current protection is a problem then depending on the system configuration. Most VFD's can control the line contactor operation as well.
 
soft start with bypass

Try Benshaw.com, we use several of their controls for our larger air compressor motors (300HP). Also their controllers continuous;y monitor a lot of parameters allowing the controller to shutdown the motor before damage can be done.
 
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what about schneider's softstarters?
They do not come with internal bypass but instead recommend usage of external by pass
 
I have never used Schneiders but I know you can buy the the starter with/without a bypass contactor from Benshaw. The bypass contactor merely takes the load off of the solid state soft start components because once the motor is at full speed the SCRs are essentially "ON" all the time and their function is essentially complete.
 
It's been a few years but I've used the Telemecanique ATS46 series in the past. In my experience, it's been a very reliable soft starter. We did use an 'at-speed' contactor on them, and if the customer specified we would add a 'bypass' contactor as well.
 

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