Electromagnetic power drive for a friction welding machine

Claim 1

An electromagnetic power drive for a friction welding machine, comprising: a first magnetic core which is stationary; a second magnetic core adapted for axial motion and rotation in relation to said first magnetic core; a power coil installed on said first magnetic core; at least one pickup coil installed on said first magnetic core; an integrator producing voltage proportional to the actual value of the magnetic flux during said friction welding, having an output and an input connected to each said pickup coil; a comparison means having an input connected to said output of said integrator, a first driving input, a second driving input, and an output; a first comparator having an input, an output, and a driving input which is said first driving input of said comparison means, to which voltage proportional to a first assigned value of the magnetic flux is applied; a second comparator having an output, a driving input which is said second driving input of said comparison means, to which voltage proportional to a second assigned value of the magnetic flux is applied during said friction welding, and an input joined together with said input of said first comparator in order to form said input of said comparison means; a control signal generator having a hysteresis output characteristic, an input connected to said outputs of said first and second comparators, and an output which is said output of said comparison means; and a voltage regulator made as a switch operated by control signals of said control signal generator, having a control input electrically connected to said output of said comparison means, and an output connected to said power coil.