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Parts for Whirlpool RBS305PDB12 Oven - AppliancePartsPros.com
See the attachment for the tech sheet
Could be that the thermal overload (item 37 in section 01) has blown.
Check it with a meter.
If blown replace it then carefully monitor the oven’s operation as a bad control board may have caused the original problem.
Also possible that you are not getting the full 240 volts.
Try flipping the breaker off/on slowly a couple times.
If still no go check the power with a meter.
If it is OK then odds are that the control board is bad.