Transformer vs. motor soft start devices
To clarify what Brian Drummond is talking about with "C" or "D" type circuit breakers - "C" type is for general purpose loads. "D" type is for loads with a high inrush current.

Using a "D" type breaker might allow the circuit breaker to restrain from tripping on inrush curent.

Excerpt from the Clipsal 4-series miniature circuit breaker catalogue:





With regards to soft starters;

It depends on the type of soft starter.

Some use an inductor or resistor or auto-transformer in series with the load, to reduce the starting voltage and hence the starting current. The inductor/resistor/auto-transformer is bypassed after a few seconds. This type would likely work well for you.

Electronic soft starters use some kind of semiconductor device (usually thyristors) to do pulse-width modulation of the voltage. This is a bit harsh and your machine may not like it.