im trying to fit a new vac motor only the new one which although being the same one is a different brand, it only has 2 wires, were the original had 3 which joined using a little 3 pin plug, presumabley earth, nuterial and positive,

)
if the new one only needs 2 wires what 2 are they,? earth and positive?

they are both black so cant tell apart?

the 3 in machine with the little plug are yellow/green (i know thats earth) brown and blue

help appreciated, craig.