Patent GB-1059081-A (GB)
Title: Arrangement for the rapid switching of drive systems
IPC: H02P29/00
Filed: 1964-03-18
Abstract: 1,059,081. Electro-magnetic clutches. MASCHINENFABRIK HEID A.G. March 18, 1964 [March 18, 1963], No. 11551/64. Heading F2L. In a control of one or more electromagnetic clutches K and a brake B in a copying lathe, wherein rapid engagement is produced by momentarily over-exciting the clutch and brake on initial engagement, the over-excitation of both the clutch and brake is controlled by a single quick-acting delay-relay X operating single contacts x and subject to adjustably delayed response under the influence of its own self inductance alone or with capacitors. In Fig. 3 (not shown) an over-exciting high voltage (U 1 ) and a nominal clutch-brake slack takeup voltage (U 2 ) are provided. A sequence is started by closing a manual or feeler operated switch (1) to energize a start-relay (S) moving contacts s from full-line to dotted-line position, bridging contacts (9, 10) to over-excite the clutch (K) rapidly from the high voltage (U 1 ) through contacts (5, 6), resistor (R 1 ), diode (D 1 ) and contacts (9, 10). After a time-delay determined by the inductance of the clutch K and the delay relay X, with adjustment by a resistor R 3 , the voltage drop across the resistor R 1  becomes sufficient to operate the delay relay X, the contacts x of which move from fullto dottedline position, breaking contacts 5, 6 and making contacts 7, 8. Clutch winding energization is thereby changed from the engaging high voltage U, to low slack take-up voltage U 2  through a diode D 3  and the clutch now slips at nominal excitation until switched off. During the whole of this time the brake B is ineffectively pre-excited to take up slack at low voltage from the line U 2  through a resistor R 4  to permit rapid engagement of the brake when required. For a stop sequence, switch 1 is opened, deenergizing the start-relay S returning the contacts s to full line position 11, 12, so that the clutch completely de-energizes under its own self inductance. The delay-relay X remains energized until its inductive current is dissipated through a diode D 2  and resistor R 2 . During this period the brake B is given a sudden overexcitation pulse from the high voltage U 1  through contacts 11, 12 and 7, 8, until the delayrelay fully de-energizes to open contacts 7, 8 and re-close 5, 6 whereupon the brake B is is returned to pre-excitation slack take-up voltage from the line U 2 . In Fig. 4 (not shown), and Fig. 5, both use a single supply source at the high energizing voltage U, slack take-up voltage being provided by a dropping resistor (Rv). Two clutches (K 1 , K 2 ) are selectively controlled by separate start buttons (1, 1<SP>1</SP>) and start relays (S, S<SP>1</SP>). Time-delay in Fig. 5 is provided in part by a capacitor (C 1 ). On closing either start switch (1) or (1<SP>1</SP>), e.g. the switch (1) the corresponding start relay (S) is energized moving corresponding contact (s) to dotted line position to over-excite and engage clutch (K 1 ) through contacts (5, 6) and (9, 10) and after a time delay determined by resistor (R 5 ), diode (D 4 ) shortcircuiting resistor (R 6 ) and charging-time of the capacitor (C,) the voltage across the capacitor (C 1 ) is sufficient to operate the delay relay (X), the contacts (x) of which move from the full to dotted line position opening contacts (5, 6) to introduce the dropping resistor (Rv) in the circuit, to cause the clutch voltage to be reduced to slack take-up voltage. Brake (B) is during this time ineffectively pre-excited for slack take-up through the dropping resistor (R 4 ). On opening the start switch (1) the start relay contacts (s) move to the full line position completely de-energizing the clutch (K 1 ) and connecting the brake (B) to the over-exciting engaging voltage (U) through contacts (7, 8) and (11, 12). After a time delay during which the condenser (C 1 ). discharges through resistors (R,) and (R 5 ) and the relay (X), the currentpassing through relay (X) drops and it deenergizes moving contacts (x) to (5, 6) connecting brake (B) to slack take-up voltage via (R 4 ).