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I acquired an old factory bench grinder. It's a 380/220 3 phase 50 Hz unit. Can someone explain how to wire this to run on single phase 220 V (household power)?

I tried simply connecting the blue and brown leads to a 220 V outlet and spinning the unit by hand but that didn't work. I can hear the motor getting power, but it won't spin up.

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marked as duplicate by winny, Charles Cowie, Voltage Spike, nidhin, Lior Bilia Nov 6 '17 at 14:45

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  • 1
    \$\begingroup\$ Buy a single three phase converter unit... \$\endgroup\$ – Solar Mike Oct 27 '17 at 10:19
  • 2
    \$\begingroup\$ That does not look like a three phase cable at all \$\endgroup\$ – PlasmaHH Oct 27 '17 at 10:20
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    \$\begingroup\$ (1) That cable in photo 3 doesn't look like the same cable in photo 2. What is it? (2) Why has one conductor got no insulation? (3) Photo 1 shows that the motor is rated for 'star' 380 V or 'delta' 220 V but this normally requires six terminals in the junction box. Yours only has three. Is there another junction box or connections somewhere? \$\endgroup\$ – Transistor Oct 27 '17 at 10:48
  • \$\begingroup\$ Buy a VFD which takes single phase input and outputs 380 V three phase. \$\endgroup\$ – winny Oct 27 '17 at 10:58
How do I wire a 380v/3 phase bench grinder to run on 220v single phase

You don't.

A device designed to run from three separate phases, each 120° apart, is unlikely to work with a single phase. Even if it is possible at all, trying to "convert" it would require intimate knowledge of the device and expert-level electrical engineering skills. The nature of your question implies you have neither.

  • \$\begingroup\$ Transistor: the cable end in photo 3 is just the other end of the cable terminating at the unit. The previous owner cut it. The comductor with no insulation is brown, the insulation seems to have been removed. There are only three terminals in the box with six wires connecting. 3 black cloth braided wires appear to be coming from the motor and 3 from the power cable (blue, brown and grey. No other junction box present. \$\endgroup\$ – Dave Oct 27 '17 at 12:33

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