VFD and RCD

[Beelsebob]

Much of the internet seems to indicate that VFDs will cause RCD systems to trip out. In the UK though the whole building tends to be protected with an RCD breaker. Does anything need to be done to make a simple 1.5 or 2.2kW spindle work on a UK residential circuit, or am I worrying about nothing?

[JohnHaine]

No problem with mine

[m_c]

VFDs can trip certain RCDs, but for a typical 2.2kw VFD it isn't likely to be an issue.

You could get lost down a rabbit hole of what could happen and what to do to mitigate it, but most of the time it won't happen.

[Neale]

Main problem with these is the EMI (electro-magnetic interference) filter on the input of the VFD - assuming that there isn't an actual fault, of course! Typical small VFDs tend not to have these fitted as standard, so no problem. The filter unbalances the load on live and neutral and the RCD trips as a result as it works by detecting this kind of imbalance. Fix is to remove the EMI filter and hope the neighbours don't complain!

[Robin Hewitt]

I bought a mill wired so one VFD could drive two motors with a switch select. By the time it arrived it was pulling the RCD and soon after the mill died completely. I replaced one VFD with two and dumped an amazing quantity of transformers, contactors, connectors, complicated switches and stuff. How they could wire that lot in just to save on the cost of one extra VFD is beyond me. Anyway, the VFD pulling the RCD was symptomatic of a being on its' last knockings :)