[Matt H.]

I am almost completely sure that electromagnets are not a legal device.

<R60> Items specifically PROHIBITED from use on the ROBOT include:
 Electric motors and/or servos different from, or in addition to, those in the Kit Of Parts, with
the exception of those specifically permitted by Rule <R59>.
 Electric solenoid actuators (note: electric solenoid actuators are NOT the same as pneumatic
solenoid valves – the latter are permitted, the former are not).

Electromagnets are defined as electric solenoids and hence can not be used.

I believe the rules are very clear on the use of electromagnets, but if you persist in your design you should definitely submit a QandA query.