Okay heres the real deal:
1) If your planer is a 240 volt (which I assume, correct me if its not) and it calls for a 30 amp circuit,,,,,,,(if the "continuous" load is no greater then 24 amps, a 30 amp branch circuit with 30 amp rated wire protected by a 30 amp overload protection device will indeed suffice, subject to code exceptions where a bigger breaker is permitted to allow a motor to start if all other requirements are met)
Then that 240 volt 30 amp branch circuit requires a 240 volt 30 AMP TWO POLE CIRCUIT BREAKER which serves as the branch circuits overload protection device........
NOTTTTTTTTTTT a 15 Amp
NOTTTTTTTTTT one Single Pole Circuit Breaker (those are for 120 volt branch circuits)
The reason you need a TWO POLE BREAKER is because they connect a pole to each of the two different Hot UnGrounDED voltage phase legs in the panelboard, and its 240 volts L1 to L2 in the Panel NOT 120 volts which is present between either leg L1 or L2 and Neutral (A GrounDED Conductor).
YES BILLY BOBS (dont want you to have a calf now lol) if you have two single pole breakers side by side with their handles tied together, that would supply 240 volts line to line. My preference is a single one piece two pole breaker but yall do as you please.
The current in a 240 volt single phase load IS NOT ADDITIVE, its the same amount of current in both legs. If the load were 20 amps and you used an ammeter on both legs L1 and L2, BOTH will read 20 amps, NOT 10 on one and 10 on the other.
Id expect the straight 240 volt branch circuit (assumes no 120 volt loads) to have three wires, two Hot UnGrounDED Phase Conductors L1 & L2, plus a third Safety Equipment GroundING Conductor (often bare or Green) that bonds to a saws outer metal case frame for safety.
AS ALWAYS if in doubt consult a local trained competent profesional electrician or engineer and dont hang your hat or risk your life on untrained Billy Bob and Bubba opinions....
Nuff said, any questions???