Thread: vfd protection

dont confuse an RCD with a circuit breaker (CB)

A circuit breaker is designed to trip on a overload condition

A RCD is designed to trip when it senses an imbalance between active and neutral and thus assumes that voltage is passing to earth...that could be you allowing the voltage to pass to earth and so it trips

circuit breaker is all you need to protect the VFD/VSD

and rcd is probably an overkill but you should have one on the switch board anyway for all power outlets protecting your life...which is what an rcd is designed to do

The circuit breaker back at the switchboard is there to protect the wiring. Case in point. I am about to install a 6mm 2 core + earth cable which will be protected by a 25A circuit breaker. An RCD is also installed prior to the CB. If I managed to find a suitable mill and connect it via a 2.2kw VSD as per Shamus' setup then I would not expect a 25A breaker to do much to protect a 9A VSD. I would fit a fuse to the VSD itself if worried.

Dean

hi mate i have a circuit breaker mounted on my lathe on the supply side of the vfd