Braking resistors essentially must absorb ALL of the kinetic energy in the spinning mass as electrical energy pulled off of the motor, then dissipate it as heat. So bottom line: if you are burning out resistors you are trying to make them dissipate more energy than they can handle in a given time period. So you either must reduce the kinetic energy, extend the time period or increase the energy dissipation capacity.
But there are two parts to a dynamic braking system; the resistors AND the DC chopper circuit that controls the energy flow into them. So you cannot simply add on resistors, because you change the resistance in the circuit and thus the amount of current flow through the DC chopper transistor, so you move from burning up the resistors to burning up the transistor in your drive, which is much more expensive.
There is a somewhat complex formula for determining the maximum braking capability of the drive that only the drive mfr can help you with, because they know what kind of “duty cycle” their chopper transistor was designed to handle. Then you will also need a good value of the amount of inertia in your washing machine when fully loaded. From that, using their formula, you determine; A) IF the system can do what you are asking, and B) what wattage and ohmic value of resistor(s) it will require.
" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden