A control system for an electric machine powered from a DC source, wherein controlled motoring and controlled braking are achieved with a single current regulator control, even when the DC source cannot accept charging current and/or the induced motor voltage exceeds the DC bus voltage. The motor control circuit comprises a DC source connected to a DC bus, a current control circuit for modulating switching devices connected across the DC bus, an energy exchange capacitor connected across the DC bus, a load resistor, a switching circuit effective when activated to interrupt a connection between the DC source and the DC bus and to connect the load resistor across the DC bus in parallel with the capacitor, and a logic circuit for activating the switching circuit during motor braking under conditions for which the modulation of the switching devices is ineffective to control the braking current.