Patent GB-1484309-A (GB)
Title: Electrically driven vehicle
IPC: B60L15/04
Filed: 1974-10-09
Abstract: 1484309 Control of D.C. motors MODERN PRODUCTION BJORN ORTENHEIM AB 9 Oct 1974 [12 Oct 1973] 43818/74 Heading H2J An electrically-driven vehicle is powered by a D.C. motor which is connectible through switching means with a plurality of batteries, there being first and second switch positions wherein the batteries are respectively in parallel and series whereby, when the means is switched from the second to the first position, the motor operates as a generator to charge the batteries, which receive the entire available charging energy due to negligible resistance in the circuit connections between the motor and batteries. As shown in Fig. 1, the motor 1 is connected to batteries B1, B2 through a fuse 8, ammeter 9, main on/off switch 6 and a thyristor element 10 shunted by the normally-closed contact 4<SP>1</SP> of a relay 4, the control circuit being completed by relays 3, 5, fuses 11, 12 and a control switch 2. Movement of a main contact 7 of switch 2 to a first position A connects batteries B1, B2 in parallel and to the motor 1 which accelerates up to half speed, the contacts of relays 3, 4 being closed and contacts 5<SP>1</SP>, 511 of relay 5 being engaged. Movement of contact 7 to position B causes relay contacts 3<SP>1</SP>, 4<SP>1</SP> to open, whereby only battery B 1 is connected to the motor through members 6, 8, 9, 10. Movement of contact 7 to position C energizes the winding of relay 5 to engage contacts 5<SP>1</SP>, 5<SP>111</SP>, whereby batteries B1, B2 are connected in series and to the motor through members 6, 8, 9, 10, allowing the motor to accelerate to full speed. If thereafter the contact 7 is returned to position A, the batteries B1, B2 are charged in parallel by the motor through members 6, 8, 9 until its generated voltage has fallen to that of the batteries. Further speed control is provided by the thyristor element 10, which is of conventional chopper and commutating circuit type, Fig. 4 (not shown). In a modification, Fig. 2 (not shown), relay 3 has additional changeover contacts and is duplicated by an additional relay (19), relay 5 is of on/off type, and the relay windings are supplied by a further battery (B3) not used for driving the motor. The additional contacts of relays 3, (19) form an AND gate controlling relay 5, whereby batteries B1, B2 cannot be connected in series before their parallel connection is broken. Otherwise the modified circuit operates in the same way as that of Fig. 1. The relays may be replaced by solid state components and batteries B1, B2 by six batteries connectible in series, parallel or seriesparallel configurations. The control switch 2 may comprise two spring-biased contacts slidable on respective cards each carrying two pairs of fixed contacts, with a third card and sliding contact being provided if the thyristor element 10 is to be included in the control circuit. Fig. 3 (not shown). Alternatively the control switch may comprise either a number of "program" discs fixed to a rotatable shaft and operating microswitches controlling the relays or a movable switch blade engaging a number of fixed contacts in turn, with contacts to reverse the motor in each case if desired.