Wheelslip

Near-synonym: wheelspin

The traction motors are connected in three parallel groups of two in series, and the mid-points of each pair of motors are connected together; the mid-point connection is used in conjunction with relays to form a device which is sensitive to wheelslip, thus leading to an improvement in adhesion.

Minor changes to control gear include the provision of automatic wheelslip protection, since these units will be operated on lines with ruling gradients of 1 in 60 or 1 in 80. Wheelslip automatically causes the main generator field excitation to be reduced; the load regulator is forced back to minimum excitation and, if operating in one of the two stages of traction motor field divert, causes reversion to full field.

Daily diagramming involves the single-heading of 1400-tonne trains over the northern banks, where wheelslip can be experienced when the rails are wet.