Electrical control systems of electromagnetic vibrators

Claim 2

A controllable supply circuit for electromagnetic vibrators including: a vibratory electromagnetic motor having a coil, a source of direct current, an electronic switching device having a control electrode connected in series with said source and said coil such that a signal applied to said electrode affects the conductivity of said sWitching device, circuit means for providing a rectangular pulse signal to said control electrode to alternately render said switch conductive and non-conductive and establish and interrupt a circuit through said coil, a circuit including a capacitor, and a uni-directional conducting device connected in parallel with said coil, said uni-directional conducting device having its polarity opposite that of said switch, and a resistance connected in parallel with said capacitance.

Claim 3

The apparatus of claim 1 where the magnitude of the capacitor C, and the resistor, R, are related to the maximum rated current of the coil of the vibratory electromagnetic motor as follows: C 50 Imax and

Claim 4

The combination recited in claim 1 wherein a unidirectional conducting device is connected in series with the input to the control electrode of the electronic switch, said unidirectional conducting device having sufficiently high voltage breakdown characteristics and a direction of conductivity such that a breakdown of said switching device which raises the electrical potential at the control electrode will not result in current flow through said unidirectional conducting device.

Claim 5

A controllable supply circuit for electromagnetic vibrators comprising: a vibratory electromagnetic motor having a coil, a source of direct current, an electronic switching device having a control electrode and connected in series with said source and said coil such that a signal applied to said electrode affects the conductivity of said switching device, circuit means for providing a rectangular pulse signal at said control electrode to alternately render said switch conductive and non-conductive and establish and interrupt a circuit through said coil, whereby when said switch is conductive the current through said coil rises with time at an essentially linear rate, a circuit including a capacitor and a unidirectional conducting device having its direction of conductivity opposite that of said switch, said circuit connected in parallel with said coil, a resistor connected in parallel with said capacitor, said resistor and said capacitor having values selected to produce decay of current through said coil at substantially the same rate as the rise thereof.

Claim 6

A controllable supply circuit for electromagnetic vibrators comprising: a vibratory electromagnetic motor having a coil, a source of direct current, an electronic switching device having a control electrode and connected in series with said source and said coil such that a signal applied to said electrode affects the conductivity of said switching device, circuit means for providing a rectangular pulse signal at said control electrode to alternately render said switch conductive and non-conductive and establish and interrupt a circuit through said coil, whereby when said switch is conductive the current through said coil rises with time at an essentially linear rate, a circuit including a capacitor and a unidirectional conducting device having its direction of conductivity opposite that of said switch, said circuit connected in parallel with said coil, a resistor connected in parallel with said capacitor, said resistor and said capacitor having values selected to produce decay of current through said coil at substantially the same rate as the rise thereof.

Claim 7

The apparatus of claim 4 further including means for varying the frequency of said pulse signal.

Claim 8

The apparatus of claim 5 further including means for varying the pulse width of the rectangular pulse signal.