A similar form of braking using this principle is regenerative braking, in
this case the motors also act as generators, except the current is fed back
into the supply rather than wasted - the NSW 46 class electric locos used
this principle, it saved on power because locos going down hill would
generate power to assist those which may be climbing at the same time -
very useful between Penrith and Katoomba.
Dynamic braking wasn't very common on Australian tramways, air brakes being
favoured. Brisbane used it on some of their early drop-centre cars. To
operate the dynamic brake, the controller handle was turned in an
anti-clockwise direction through a series of brake notches on the
controller - the reverse process to the notching up process for
acceleration.
It was however very common on overseas trams - particularly those
originating in Britain. Australia tended to follow the American practice.
David Bennetts