I have dsPICDEM MCHV-2 Development Board and three phase induction motor. I don't know how to connect the motor to the development board. I have connected three lead wires of the motor to the three outputs designated as M1, M2 and M3. But where should I connect the protective ground of the motor? I haven't found answer to my question in user's manual. Thanks in advance.


The protective ground of the motor should be a connection from the metal frame or housing of the motor to earth. If the motor's ground terminal is not obviously a connection to the frame or housing, check with an ohmmeter to make sure it has no connection to the motor windings. If it is only connected to the motor frame or housing, it should be connected to an earth ground, preferably the protective ground terminal of a power outlet. It could also be connected to a cold water pipe.

  • \$\begingroup\$ Thank you for your reaction Mr. Cowie. For specification: My motor has only some screw on his housing and I haven't received any wire for connection of the housing to some ground. The Development Board is supplied by common PC cable so I have no easy access to protective ground terminal of a power outlet. Would it be possible that the protection against electric shock is realized by residual-current device in my electrical installation? \$\endgroup\$ – Steve May 3 '16 at 14:38
  • \$\begingroup\$ Yes. The RCD will protect from electric shock. Since the motor is powered by 48 V if I recall correctly, you probably don't really need to connect it to ground. \$\endgroup\$ – Charles Cowie May 3 '16 at 15:11

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