Lascelles Motor demo model

paul r

Every time we come to use this demo it is a massive fiddle to get it to work . Any tips to get it work first time ?

Possibly dirty wipers or commutator, check there's good connection on the wiper, not much else to go wrong. Might sound silly, but if you're not using batteries, check the students are using DC.
Can you move the magnets? If so, make sure they're opposing poles - you could also try different ones in case those have lost their strength.

Are the wipers fairly tight on the commutator? Have you tried it just holding banana plugs against the commutator?

Even with everything perfect you sometimes need to give motors like that a little shove to get them going.
If there are three sectors on the commutator the "brushes" will need to be truly vertical to prevent shorts. The rotor suggests its a three pole, coreless, motor. As above the friction of the brushes can be enough to stop it starting on its own. Perhaps make the brushes thinner to give more "spring"?? That is, small deflections will cause less change in force as the uneven commutator spins.
If you don't find the answers here, I have found the tech support at Lascells to be excellent, it's worth getting in touch.
They're happy to help and know their stuff.