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>You'll find that on welders, too, where the main power
>is 220 but the blower or wire feed motor is 120. Also
>on dryers or kitchen ranges where there's a clock or
>lights that are 120 volt. The neutral HAS to be in
>there.
Well..... better welders and most all machine tools have control
transformers so that all the contactor coils, buttons, fans, etc are powered
by 120. All you have to do then to change the voltage of the machine is
change out the contactor heaters and reconfigure the motor(s) windings and
the line side of that control transformer. The only machine I have that uses
the neutral has a 5 wire plug (3 phase, neutral, and ground) because in
addition to the drive motor, they tap off 3 seperate 120v phases for other
internal uses, thus a neutral is required, else you could pop for a
transformer, which actually is the better way to do it.
je
This archive was generated by hypermail 2b29 : Sun Jul 02 2000 - 23:51:27 PDT