That one is 3phase and the voltages desired, but there is a caution. It is a wye autotransformer. And has no voltage adjustment taps. Your wanting to feed it in reverse from your RPC. The RPC output has one leg that has a higher voltage to ground, Essentially its just a delta output, with one coil center tapped for the neutral and ground. This arrangement gives you one phase leg that is higher voltage to ground than the other two.
From a utility supplied system like this that high leg voltage would be by design 208V to ground and sometimes slightly higher depending on loading.
Your RPC generated leg’s voltage to ground may be even higher since it is typically boosted by capacitors, you could hook up your RPC and test its generated voltage to ground to see how much higher voltage it runs at compared to the other two legs which will be at around 120V as supplied by your utility.
The reason for telling you this is, with an wye auto transformer your high voltage in on one leg, will give you high voltage out on one leg. The voltage from leg to leg should be close to normal or around 600V, but one of those legs will exceed 520V to ground.
With a standard 600V wye system all 3 legs would be 347V to ground. it should work OK for you but do be aware that the output voltages will measure different, each leg to ground, because your feeding it from a center tapped delta that has a wild leg voltage and the auto transformer you found as no additional taps to adjust the voltage.
