Glad you have restored it to operation, though it sounds like a bit of a beast, perhaps, given they could not draw a bridge rectifier correctly, the maker's datasheet was muddied with figures for a larger model. Thinking in terms of not cooking things, what stops the DC flowing  when it is all stationary and  no longer needed ?

The stopping force is proportional to the B field, in turn proportional to the DC current so yes  some peak current limit in the form of a resistance on the DC side would do. I'd be less sure of using any resistance in series with the transformer primary, as while the brake is not applied the transformer load is almost nil, so the voltage reduction is not very much at the instant the brakes come on, and yet may be too much once the braking current has started to flow. Equally having a sharp initial brake, and then a more gentle slow-down may be quite acceptable.


Or, as a quick try out, if you have 110v in the shop, how well does it work with that on the primary instead of 240? That would show you the effect of halving the voltage, and the voltage division would not be so load dependant. I might try a lamp dimmer, but not all designs of dimmer are happy on an inductive load. The simplest is resistance on the load side, and wire wound resistors of the metal clad kind are very forgiving of gross overloads (being little more than a heating element cast in ceramic in a metal tube ) Resistors that are a light evaporation of metal or other conductor on a ceramic rod (metal film / carbon film) tend to be self-fusing in overload, so I'd avoid those.


Estimating the resistor values may be a bit odd, as you may think that one looks at the voltage and the windings resistance and there are the amps, but the  winding is a bit of a complex thing, and really the current will build slowly though the inductance.  You may think you need 10A, and at 110V, a total of 11 ohms will do, but that is not the full story,  so some experiment may be needed. You  may want to design a dropper with a no of higher value resistors in parallel, both to allow  some adjustment, and to provide  some be robustness against any single failure.

Glad you have restored it to operation, though it sounds like a bit of a beast, perhaps, given they could not draw a bridge rectifier correctly, the maker's datasheet was muddied with figures for a larger model. Thinking in terms of not cooking things, what stops the DC flowing  when it is all stationary and  no longer needed ?

The stopping force is proportional to the B field, in turn proportional to the DC current so yes  some peak current limit in the form of a resistance on the DC side would do. I'd be less sure of using any resistance in series with the transformer primary, as while the brake is not applied the transformer load is almost nil, so the voltage reduction is not very much at the instant the brakes come on, and yet may be too much once the braking current has started to flow. Equally having a sharp initial brake, and then a more gentle slow-down may be quite acceptable.


Or, as a quick try out, if you have 110v in the shop, how well does it work with that on the primary instead of 240? That would show you the effect of halving the voltage, and the voltage division would not be so load dependant. I might try a lamp dimmer, but not all designs of dimmer are happy on an inductive load. The simplest is resistance on the load side, and wire wound resistors of the metal clad kind are very forgiving of gross overloads (being little more than a heating element cast in ceramic in a metal tube ) Resistors that are a light evaporation of metal or other conductor on a ceramic rod (metal film / carbon film) tend to be self-fusing in overload, so I'd avoid those.


Estimating the resistor values may be a bit odd, as you may think that one looks at the voltage and the windings resistance and there are the amps, but the  winding is a bit of a complex thing, and really the current will build slowly though the inductance.  You may think you need 10A, and at 110V, a total of 11 ohms will do, but that is not the full story,  so some experiment may be needed. You  may want to design a dropper with a no of higher value resistors in parallel, both to allow  some adjustment, and to provide  some be robustness against any single failure.