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It could be necessary changing both contactors.
A2) There is not a good contact either on TI NA or on TA NC, due to dust, dirt or
any particles which prevent a valid contact.
Clean contacts by means of compressed air; if necessary remove dirt apply-
ing a soft abrasive movement.
It could be neccessary changing both contactors.
A3) The most probably reason is that the normally closed contact of the braking
contactor doesn’t make a good contact towards the battery negative for dust,
dirt or because the contact doesn’t lean completely for a mechanical defect
of the contactor.
It could be necessary to replace the contactor.
It may be due to 1 of following causes of motor connecting interruption:
a) brushes lift up from collector (fig.1).
b) brushes’ cable burn up (fig.2).
c) Missing the braking contactor negative cable (fig. 3)
d) Interruption either on motor winding or on motor itself cabling.
H2B diagnosis traction