# brushless faraday disc physics question

Joined Jan 9, 2015
13
It is said that due to the Lorentz force there is a charge imbalance created on the rotating Faraday disc even when there are no brushes or load connected, now it is also commonly said that if one would attach a load physically to the rotating disc from center to rim no current would flow because both in the load wires and the disc itself currents would be generated in the same directions.

My question is, is it possible to create a Faraday disc/homopolar generator where the load is rotating together with the disc (or cylinder as in cylindrical homopolar generator) using a physical connection if a condition is met where the homogeneous B field is kept only to the current generating part and does not cross or interfere with the wires leading to the load?

This questions has caused alot of confusion and I would love to hear some answers.

I have some explanations myself but i'll first want to hear your thoughts.

#### BR-549

Joined Sep 22, 2013
4,938
"Faraday disc even when there are no brushes or load connected, now it is also commonly said that if one would attach a load physically to the rotating disc from center to rim no current would flow because both in the load wires and the disc itself currents would be generated in the same directions."

??? What does that mean?

Joined Jan 9, 2015
13
normally the disc rotates and has slip contacts which form a stationary loop with the load, current is generated in the disc via the Lorentz force and so a current is driven through the brushes and through the load.

now imagine you have no brushes but instead physically solder the load wires onto the disc or some other geometry of a conductor that moves through a homogeneous B field, so the load co-rotates with the conductor, my question was/is whether one could still get current through the load in such a scenario?

the assumption is that the setup has to be such that the B field lines are not cutting the load wires and so generating a counter current in the same direction like would happen if one simply added a fixed load onto a spinning disc because then no current could flow, but if the B field is set up correctly could then current flow just as it does when the load is kept stationary and current is taken off the disc via brush contacts?

I hope everyone here understands what I'm talking about.

#### BR-549

Joined Sep 22, 2013
4,938
Sorry, I can not picture what you are talking about. What is your objective?

#### BR-549

Joined Sep 22, 2013
4,938
Can you show an illustration? Faraday and others worked with different configurations of the device.