Following on from the question here.

I note that some electric motors have dual black and dual blue leads.

Does this mean that there are two positive and two negative sides to connect up? Or do I just connect one of the black leads to power and the opposite black lead to negative? If so, what then happens to the blue leads?

enter image description here

  • \$\begingroup\$ Those motors seem to be powered by AC (alternating current) so there is no "positive" or "negative". There will be "live" and "neutral" instead. \$\endgroup\$
    – Transistor
    Commented Sep 20, 2022 at 6:19
  • \$\begingroup\$ yes that is correct. Just that here in Australia, our mains lines in household wiring are red and black...blue and brown are found on electrical appliances, however they must eventually correlate with red and black on the mains. So I call them positive and negative but I do understand i should have used the terms active and neutral (and green is earth). Point is, how should the above motors be wired into Active, Neutral and Earth mains? (which wires connect to what on the motor in the image attached?) Which are active on these motors and which are the neutrals? \$\endgroup\$
    – Adam
    Commented Sep 20, 2022 at 7:29
  • \$\begingroup\$ The motor knows no difference between active and neutral. Looks like the power is applied to the black wires. You can wire the blacks anyway you like. If unsure, try both possibilities. This was outlined in your previous question. The blue wires go to the brushes which power the armature. In series are the stator windings. This is commonly referred to as a ‘universal’ motor - it works with AC or DC. \$\endgroup\$
    – Kartman
    Commented Sep 20, 2022 at 13:07

1 Answer 1


It's a universal motor.

The black wires run from the motor terminals to the field windings and the blue from the field windings to the carbon brushes.

Here's the schematic.

enter image description here

The capacitor is for EMI suppression.


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