Hey Julian,
what Charley calls “spindle” in that post that you reply to, is not a spindle, he means the Makita hand trim router. NEVER connect a VFD this way! His posting is not about spindles!
A spindle is a slim, usually cylindrical three-phase asynchronous induction motor that is driven by a three-phase current with variable frequency, so Charley used the term wrongly.
See here for Differences between router and spindle.
If you have a router with 220 V (like this one), you need a relay that can switch 220 V. A router can be switched on and off by the ‘tool-enable’ pin 15 and ground of the 25-pin I/O port (e.g. via a breakout box). These two pins have to be connected to the control circuit of the relay.