Balance resistors for series capacitors

Based on the description I believe this circuit is supposed to protect these capacitors with a lower voltage rating ie 35V from the 100V voltage source and if that’s the case this circuit is pretty deceptive. Starting a simulation in EC with passive components connected to a voltage source will start with stable values as if it had been left running for an arbitrarily long time and as such the voltage is evenly divided among these three capacitors. Including a switch in series with the voltage source and starting with it open before starting the simulation will give a more realistic power on sequence which will involve RC charging characteristics in this circuit. In particular when first switched the top capacitor, having the lowest capacitance, will have the largest voltage drop of ~57.1V for a while as the voltages begin to conform to 1/3 Vin by charging/discharging through the 1M resistors. Using a switch and speeding up the simulation shows that process can take several seconds which could leave the top capacitor possibly going over its voltage rating for a few seconds. Disconnecting the resistors completely and just examining the capacitor voltage divider shows the voltages the capacitors will quickly charge up to at first.

If an "increased" voltage rating is all you want, then put capacitors of the same capacity in series. That's how it's done in power supplies. Why someone would put capacitors of different capacities, I don't understand.

Even with capacitors of equal capacities, that resistor divider is still needed, because over time the capacitors start wearing out and end up with different values of ESR and capacity.

@snowfats, thank you so much for taking the time to write that. I added a switch as you said and I can now see that the capacitors are going over the voltage of 1/3 Vin. I made the circuit here to practice some circuits from a book, I'm not going to use the circuit in the end. However it's great that I now understand that when turning on the power supply it will take some time for the capacitors to reach the intended voltage.

@PrathikP I put capacitors of different values just to play around, I'm not going to use this circuit. Thanks a lot for the feedback though. Do you think that for example power supplies, resistor dividers are always needed for capacitors in series?

yes, you need in this case of series connection a balancer. In this case here its he most simple balancer you can think of. Its the same problem as you will have when you charge batteries in series. Same do charge quicker others slower, cuz they are different in capacity. As higher the charge current is as more conplex your balancer gets! Simple resistors are only possible if the objects you chargae are almost equal in capacity or better said matched to ite balacing resistor.

@hurz, thanks a lot for the explanation, I learned a lot from these comments.