electromechanic812291
DC Injection brake from RDM
An AC induction motor can be brought to a rapid standstill by injecting any two phases with a current-controlled DC supply until the motor stops. This one is off a pedestal drill. It was made in the UK by RDM. It uses GEC contactors and an IR thyristor for the DC. Judging by the state of the components, I think it's spent the last 30 years powered up continuously. A few capacitors, resistors and joints to attend to and it's working again.
DC Injection brake from RDM
An AC induction motor can be brought to a rapid standstill by injecting any two phases with a current-controlled DC supply until the motor stops. This one is off a pedestal drill. It was made in the UK by RDM. It uses GEC contactors and an IR thyristor for the DC. Judging by the state of the components, I think it's spent the last 30 years powered up continuously. A few capacitors, resistors and joints to attend to and it's working again.