Patent GB-274964-A (GB)
Title: Improvements in or relating to electric regulators
IPC: G05B5/01
Filed: 1926-04-29
Abstract: 274,964. Igranic Electric Co., Ltd., and Spaink, J. H. Abbink-. April 29, 1926. Regulation, automatic. - A voltage regulator. which according to the Provisional Specification varies the tappings of a trarsformer, is arranged to vary the voltage in steps, there being means to ensure that a complete step is made at every adjustment, and means to ensure that a definite time interval elapses between any stop and the succeeding step so as to prevent over-regulation and consequent hunting. In the system shown in Fig. 1 the actual regulator is a drum (not shown) driven by a reversible motor m and having associated therewith another drum d and a tracer device t, variation of voltage causing either the relay vl or vr to close. Assuming the drum d is in its mid-position, corresponding to no voltage boost and the auxiliary supply N<1>, N<2> becomes energized, thereupon no-volt relay n<1> is energized over N<1>, 7. d, 6, n<1>, 5, N<2> causing contacts n<2> to open and n<3> to close to complete a maintaining circut N<1>, 7, n<3>, n<1>, 5, N<2>, and also n<4> to close, the contacts n<4> being in circuit with relays controlling the steps of the boost. Further, relay h<1> is energized over circuit N<1>, sr<6>, sl<6>, h<1>, N<2> and contacts h<2>, h<3> close. The system is now in an operative state. Assume that the voltage to be controlled falls below its required value, the relay vl closes completing the circuit N', tl<1> contacts of vl, h<2>, c<2>, c<1>, h , N<2>, thereupon contacts tl<2> close after a, time interval and complete the circuit N<1>, 7, d, 1, sr<1>, sl<5>, tl<2>, c<2>, c, h<3>, N<2>. This causes energization, of sr, with consequent closure of contacts sr<2> and operation of the motor m to cause an increase of voltage boost. Contacts sr<3> also close to energize a brake coil b over N<1>, sr<3>, b, 5, N<2>, and removal of the brake from the motor. Contacts sr<6> open to de-energize h<1> whereupon contacts h<2> open at once and contacts h<3> after a delay. Opening of contacts h<2> breaks the circuit of relay tl<1> and therefore, contacts tl<2> open, but the circuit of sr<1> is maintained over N<1>, 7, d, 1, sr<1>, sl<5>, sr<4> (now closed). h<3>, n<2>. The contacts h<3> do not open until after the motor has moved sufficiently for the tracer t to close its contacts to shunt the contacts h<3>. The motor therefore continues to run until a complete regulating step has been made ,whereupon the tracer t opens and brakes the circuit of sr<1>, thereby opening the motor circuit at sr<2> and the brake circuit at sr<3> so that the brake is applied to stop further rotation of the drum. Contacts sr<6> reclose and re-energize relay h<1>, the contacts h<2>, h<3> of which close after a definite interval, thereby preventing further actuation of the motor m until this interval has elapsed. After h<2>, h<3> close the above operation can be repeated if the voltage is still low, if however the voltage is high, relays vr, tr<1>, sl<1> operate instead of relays vl, tl<1>, sr<1> and the motor m runs in the opposite direction. If at any time the supply N<1>, N<2> fails, the no-volt relay is de-energized, and upon resumption of the supply the relay cannot close until the drum d is returned to its normal position automatically by the energization of sl<1> over N<1>, 7, d, 3, sl<1>, sr<5>, 4, n<2>, 5, N<2>. Manual operation is obtained by placing contact c<1> an c<3> instead of on c<2> and using push button pl or pr. In the, system shown in Fig. 2, the motor m is supplied from the single phase supply N<1>, N<2>, and is provided with a starting winding m<2>, and two additional relays g<1>, ss<1> are used, and the no-volt relay functions in a similar manner. Assume that the voltage to be controlled rises above its required value, the relay vr closes completing the circuit N', tr<1>, c<2>, c<1>, h<2>, ss<3>, N<2>, thereupon contacts tr<2> close after a time interval and complete the circuit N', 1, d, 2, sl<1>, tr<2>, c<2>, c<1>, h<2>, ss<3>, N<2>. This causes energization of sl<1> with consequent closure of contacts sl<2> in the starting winding m<2>. Contacts sl<3>, sl<4> also close to complete the circuit N', sl<3>, sr<6>, g<1>, sl<4>, N<2> energizing relay g<1> and completing the main winding m<1> at contacts g<2>, g<3> so that the motor operates to reduce the boost. Contacts g<4> also close to complete N<1>, 1, b and h<1> in parallel, g<4>, 5, N<2> so that the brake is removed and the contacts h<2> are opened. The opening of contacts g<5> de-energizes the relay ss<1> and contacts ss<3> open immediately and together with the opening of contacts h<2> break the original circuit for relay sl<1>, which however remains energized over N<1>, 1, d, 2, sl<1>, sl<5> (now closed), ss<2>, N<2>. The contacts ss<2> open after a delay and thereupon sl<1> is de-energized to cut out the winding m<2> but in the interval a maintaining circuit for the relay g<1> has been established by the tracer t over the circuit N', t, g<1>, g<2> (now closed), N<2>, so that the motor continues to run until a complete regulating step has been made, whereupon the tracer t opens its contacts and breaks the circuit, of relay g<1>, causing the motor to stop, the break to be applied and the relay h<1> to be de-energized. Consequent reclosure of contacts g<5> causes re-energization of relay ss', but contacts ss<3> do not close for a definite interval thereby preventing further actuation of the motor until this interval has elapsed. After ss<3> close the above operation can be repeated if the voltage is still high, if however the voltage is low, relays vl, tl<1>, sr<1>, operate instead of the relays vr, tr<1>, sl<1>, and the motor runs in the opposite direction.