Electromagnets - McMaster

[Jon Stratis]

Be very careful on how to use your electromagnet.

<R46> Items specifically PROHIBITED from use on the ROBOT include:
A. Electric motors and/or servos different from, or in addition to, those listed in the 2011 KOP Checklist, with the exception of those specifically permitted by Rule <R45>.
Electric solenoid actuators (note: electric solenoid actuators are NOT the same as pneumatic solenoid valves – the latter are permitted, the former are not).

In the past*, we've seen the GDC rule that an electromagnet could be considered a solenoid and thus be prohibited depending on its use. Specifically, if you used the electromagnet to create any motion (for example, turn it on and it pulls a lever from one location to another), it would be illegal. An electromagnet that was utilized specifically for the purposes of attachment would be permitted (using the same example, a motor moves the lever into the desired position, then the electromagnet activates to hold it in position).


I would highly recommend asking the GDC about electromagnet applications with regards to the above rule.


*Please note that past year GDC rulings don't necessarily apply to this year... but they can give a very good indication as to how the GDC will rule with regards to certain applications and similar rules.

[Chris is me]

Knowing (vaguely) the possible application of the electromagnet - I think a spring loaded locking pin would work better. Think like the little nubby clips on chair legs, or those things that Razor scooter handlebars are held in with.

[MrForbes]

In the past, using electromagnets to release things has been OK, but using them to move things has not been OK.

As mentioned, study the rules, and ask Q&A if there is any doubt. Be sure to describe exactly what you intend to do with the electromagnet.

[Hugh Meyer]

We tried to use one last year to hold and release our kicker. The problem was the release time. When the power is removed from these they hold on for about a second or so before the field decays enough to let go. If you have a diode across it to kill the back emf it takes even more time. They are heavy as well.

-Hugh

[Stepol]

We use electromagnets on Longarm Quilting Machines for channel lock. The magnets are spring-loaded so that the springs are compressed when the magnet is engaged and then the springs cause the magnet to release as soon as the power is removed. We are considering using this type of magnet.