Patent GB-291847-A (GB)
Title: Improvements relating to electric remote control and supervisory systems
IPC: H02J13/00
Filed: 1927-03-04
Abstract: 291,847. Beatty, W. E., (Electrical Research Products, Inc.). March 4, 1927. Selective distant control systems; bell and audible signalling systems.-Relates to a remote control system wherein circuit breakers or other apparatus at one or more substations may be controlled and supervised from a central station, water levels may be ascertained and the loads on generator sets may be controlled. Provision is also made for telephone communication between the stations. The Fig. shows a control station CS and one substation RS having two circuit breakers A ,B, a water level gauge C and apparatus D for raising or lowering the load on a generator. The condition of the apparatus at the substations is supervised by transmitting either continuous or intermittent audible signals. The various units have associated step-by-step selectors 15 - - 18 which are operated by alternate positive and negative impulses transmitted over the line wires L', L<2>. To facilitate satisfactory telephonic communication the control and substations are coupled to the lines by transformers 1, 2. Ascertaining positions of circuit breakers. Assuming it is desired to ascertain the condition of circuit breaker B, a foot switch 3 and the impulse transmitter of the control station are operated. The switch 3 energizes a relay 4 which closes the signalling circuit and the impulse transmitter pulses a relay 9 to send alternate positive and negative impulses over the line wires L', L<2> to operate all the selectors at the substations. The transmitted impulse code causes the corresponding selector 16 only to be held, all the remaining selectors being released. The selector 16 is held in engagement with contact 19 by a holding arm 20 which co-operates with a pin 21. A circuit is then closed from battery 22, arm 20, pin 21, selector wheel, arm 16, contact 19, through lead 23 and auxiliary contacts on the circuit breakers to the winding of relay 27, through its back contacts. The relay operates and transfers the circuit to a buzzer 28 which transmits current variations over the line wires to operate a hooter 31 at the control station. Upon operation of the relay 27 its own circuit is interrupted and the buzzer is stopped. Retraction of the armature however causes re-operation of the relay and buzzer. An intermittent audible signal is therefore given at the control station to signify the " open " condition of the circuit breaker B. If the circuit breaker is " closed " the buzzer 28 is permanently energized over the upper contacts of the lower auxiliary group associated with the circuit breaker and a continuous signal is given at the control station. If it is not desired to operate the breaker the foot switch 3 is released to release the relays 4, 9 the relay 9 being released before the relay 4 to send a further impulse over the line wires to release the selector 16. Operation of circuit breaker. To "close " the circuit breaker two farther impulses are dialled to set the arm 16 on contact 34, and thereby energize the operating solenoid 24. The circuit breaker is held closed by the armature of relay 63. If the breaker is closed, the impulse may be transmitted after selection to energize the relay 63 and thereby attract the holding armature to cause the circuit breaker to open. Supervisory signalling. When the circuit breaker changes its position the holding circuit of a relay 37 is momentarily opened. Upon retraction of its armature a permanently or intermittently closed circuit is established over one or other sets of contacts of the lower auxiliary group according to the position of the circuit, breaker. To stop the operation of the audible signal the despatcher dials further impulses to operate the selector into engagement with contact 35. A circuit is then closed for relay 37 over the upper auxiliary group of contacts and the buzzer circuit is opened. If a signal is caused by the automatic operation of a circuit breaker, the despatcher dials the code of each circuit breaker. The cessation of the signal then notifies him of the operated unit. Indicating water levels. The selector 17 is operated until a contact in the group 46<1> - - 49<1> corresponding to the contact in the group 46 - - 49 which is engaged by a float operated contact 44 is selected, and an intermittent audible signal is given. Controlling load on generators. The selector 18 controls the selection of one or other of the relays 52, 53 adapted to close the circuits of motors 54, 55 which control the field rheostat for respectively raising or lowering the load. An intermittent or continuous signal is given according to the nature of the control which may be stopped by releasing the foot switch 3. Telephone communication. Telephone sets 61. 62 are provided and an attendant at the substation may be called by a bell 59 which is operated by the selector 18.