37 Maintenance, assembling, repair and maintenance assistance for all of the following, namely, for electric motors, electric apparatus and instruments, namely, frequency inverters, electronic controllers for soft-starters, motor control units, electric circuit breakers, medium voltage cubicles, servoconverters, converters, power transformers; Maintenance, assembling, repair and maintenance assistance for all of the following, namely, for programmable controllers, namely, electronic control boards, speed regulators, Proportional, Integral and Derivative control (PID) regulators; Maintenance, assembling, repair and maintenance assistance for all of the following, namely, for motor transport units, namely, maneuver and control units, fuses, contactors, relays, surcharge relays, motor-protection relays, electronic relays, gauges, electronic control panels, dielectric transformers, electronic signaling keys, electronic controllers for starters; Maintenance, assembling, repair and maintenance assistance for all of the following, namely, for linking terminals, namely, electronic couplers, and keypads, switches and knobs for the aforementioned goods; Maintenance, assembling, repair and maintenance assistance for all of the following, namely, for electrical soft-starters, variable frequency drives; Maintenance, assembling, repair and maintenance assistance for all of the following, namely, for starters for electric motors; Maintenance, assembling, repair and maintenance assistance for all of the following, namely, for soft-starters for motors; Maintenance, assembling, repair and maintenance assistance for all of the following, namely, for structural and replacements parts therefor for the aforementioned goods within this class