Scanners, Overlap relays, Isolation switches Cut-outs London tote

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This page contains a photograph, which is one of several belonging to the photo gallery pages, which are part of several pages relating to the invention of the world's first automatic totalizator in 1913 and Automatic Totalisators Limited, the company founded to develop, manufacture and export these systems.


This technology history image shows a close up view of part of the Distributor and Relay Board, or what in the digital computer era would be called the front end system, of the Julius Totalizator manufactured by Totalisators Limited, the U.K. associated company of Automatic Totalisators Limited. This installation was at White City Stadium in London. This is the largest of the Julius tote installations that I am aware of supporting 320 betting terminals or TIMs (Ticket Issuing Machines).

Time Division Multiplexers before electronics

This is a close up image of part of the Julius Tote Scanners, Relay panels and Switchboard and is part of one of the first Large Scale Real Time Multi User Systems. The writing on the back of the photo reads White City London - but typical of any tote Distributor and Relay Board in English Julius Totes.

To clarify any confusion, Scanners and Distributors are synonymous names attributed to the circular devices at the bottom of the racks in this image, with my perception being that Scanner was a more modern name probably appearing with the advent of the computer era as the electronic counterpart to these electromechanical devices, were also called Scanners. The Scanners/Distributors seen at the bottom of the image, have an inner unbroken ring and a broken concentric outer ring consisting of studs. There are three arms seen radiating from the centre of each hub, separated from each other by 120 degrees. Two of the arms are shorter than the third and they are in electrical contact with the inner continuous ring as the arm assembly rotates. The third arm is longer and it makes electrical connections with the individual studs in the broken ring as this arm passes over them. In operation the arms rotate, driven by an electric motor, and the arms electrically connect the unbroken ring to the studs in sequence. Nowadays, these devices are known as time division multiplexers yet these devices existed long before the advent of digital electronics that made time division multiplexing a common concept. These distributors create activation pulses for the Betting Circuit involving the TIMs, amongst other devices, which are attached one to each stud. If the selected TIM has a transaction pending, a transaction cycle begins recording the transaction on both the related Horse Adder and the Grand Total Adder and the selected TIM prints a ticket. Each distributor is connected to a single solenoid in all the adders, a particular Horse Adder being selected by the TIM's horse selector arm and the Win/Place selector knob at the end of the horse selector arm. These adders are visible in the first and second photographs of the White City section of the Photo Gallery, to which this image belongs. As there are eight studs on each distributor, with a TIM attached to each one, eight TIMS are scanned by each distributor. Hence each solenoid in the adder causes the transactions from a group of eight machines to be recorded by the solenoid's associated escapement wheel.

Following is an extract from a company document titled Automatic Totalisators Limited Description of Electrical Circuit Diagrams. Note that this old document calls the scanners distributors and the TIMs are called Issuers:

DISTRIBUTORS:
There are a pair of Distributors for each Group of Issuers, that is for each Escapement, one for Win and one for Place. Each distributor has 8 contact studs and a common contact ring and a contact arm is continually rotated thus connecting the ring to each stud in turn. The distributors are driven at a speed of about 90 revolutions per minute by means of a motor and suitable gearing.

The eight studs are connected to the 8 issuers in the group and the common ring is connected to the corresponding Grand Total Escapement, so that the distributor serves to connect the 8 issuers in the group to the one escapement magnet in turn, that is the circuit is only completed through one issuer at a time even if the whole 8 issuers have their handles depressed at the same instant. This enables one escapement to record the bets from 8 issuers.

When an issuer handle is depressed, the Betting Circuit is not completed until the Distributor Contact arm reaches the stud corresponding to that issuer. The Issuer Trip Coil plunger is arranged so that it will operate and so open the Betting Circuit again before the Distributor reaches the next Contact stud, thus enabling the escapement to make its return stroke and be ready to record the bet from the next issuer in the group if its handle has been depressed.

Above the distributors are overlap relays, which hold the transaction cycle voltage from the distributor until the end of the transaction cycle after the arm has passed the stud. The relays are seen in banks above each group of distributors. Looking at the centre group of six distributors, three in the top row and three underneath, there is a matrix consisting of six across by eight down of relays, located directly above the six distributors. Each column of eight relays provides one relay per stud on a single distributor and the six columns of relays are one for each scanner in the group of six. The six columns or relays have labels on top of each of them that read: A3 B3 C3 D3 E3 F3. The black relays have windows in the front of them in which the contacts of the relays can be seen.

Following is another extract from the same company document:

RELAYS ON DISTRIBUTOR BOARD:
There are a pair of relays, one for Win and one for Place for each Issuer.

These relays serve to provide a definite time for the Issuer Trip Coil to function even if the Issuer Handle is depressed just as the Distributor Contact arm is leaving the Contact Stud corresponding to that Issuer.

The relay coil is connected in series with the Trip Coil and escapement magnets and so is energised when the Betting circuit is completed. The relay contacts are arranged so as to short circuit the distributor when the relay closes. Thus the Betting Circuit is maintained when the Distributor Contact arm leaves the contact stud and is only broken by the Issuer Trip Switch. The relay is very quick in operation and will close and so maintain the circuit if the Issuer Handle is depressed just as the Distributor Contact arm is leaving the contact stud.

Above the relays are isolation switches which are arranged in the same matrix as the overlap relays and share the column labels of the relays A3 B3 C3 D3 E3 and F3. These switches are used to isolate any faulty ticket issuing machines from their associated distributors. Above these six columns of switches are six labels which identify the value of the escapement wheel in the Horse Adder that they are attached to which read: 2/- 2/- 2/- 10/- 2/- 2/-, which are all shilling amounts. In the top row are the Cut-out Relays that are mentioned below. There is a close up view of one of these Cut-out Relays, which today would be called a circuit breaker, in the following image in the Photo Gallery. Click on the image to go back to the Photo Gallery index. Above the cut-out relays there are what look like circular cavities in the panels, one for each column of equipment with a circular dark trim attached to the perimeter of each cavity with three bright coloured tacks. A small white triangle can be seen in many of the cavities, in a high resolution version of this image. These white triangles all seem to be pointing in different directions, which seems to imply they might be in motion when the system is in operation, which does not seem probable to me. Speculating, I think it is most probable that these devices are alarms that identify a tripped cut-out relay whether it be a light or a flag. This is in keeping with the philosophy of the escapement alarm lights above each adder in the machine room.

There is some technical text on the back of the photograph shown in the image. I have included it here to connect with the mention of the Cut-out Relays in the last paragraph. The first sentence does not read well however I have copied it verbatim:

Cut out Relays wired in distributor common so that any excess amperage due to overlapping of bets from TIMs or faulty circuit breaker in any TIM in the group. Cut out relay is set to trip at just under 2A usually 1.85A. Thus if any TIM maintains its betting circuit unduly the plunger of cut out has time to rise and open its own circuit. If two issuers, by a wiring error, were on one TIM relay and betted simultaneously the cut out would instantly come out owing to the excessive amperage thus revealing the fault at once.
From a simplistic functional perspective, as opposed to implementation, I see the the Scanners/Distributors and associated equipment as being in the middle of the Betting Circuit, mentioned in the Automatic Totalisators Limited Description of Electrical Circuit Diagrams document, as they constitute the front end system that interfaces the TIMs to the Adders. In this view at the end of the betting circuit are the Adders where the transaction is recorded and the TIMs are at the start of the Betting Circuit, as nothing happens on a Julius Tote except for the rumbling of the mainframe drive motors and scanner drive motors in the machine room, until someone buys a ticket, which is issued from the TIM.

As the distributors are an essential part of the Betting Circuit I have included another extract from the company document mentioned that gives an example of the path of the betting circuit which obviously includes the path through the distributors.

To illustrate the operation of the Betting Circuit more clearly, assume that No. 22 Issuer is to Issue a 'Win' Ticket on No. 3 horse. The circuit will then be as follows-
  1. From - pole of Main Betting Circuit Switch on Main Switchboard to common side of Starter Switches on Control Room Switchboard.
  2. Though No. 3 'Starter' Switch (assuming that No. 3 Horse is a Starter and the switch has been closed) to the Betting Circuit Switch on No. 3 Win Horse Unit Fuse Board.
  3. Through Betting Circuit Switch, Betting Circuit Fuse, Escapement Cutout Relay Contacts, No. 2 Escapement Fuse to No. 2 Escapement.
  4. From No. 2 Escapement to No. 3 Contact on the Win Horse Selector Segment of No. 22 Issuer.
  5. From this contact through Horse Selector Brush (which will be on this Contact if Handle has been depressed in No. 3 Hole in the Selector Plate and with the Handle Knob in the outer or 'Win' position) through Handle lock Switch (which will close when Handle is depressed) through Trip Coil, Trip Switch, Issuer Switch, and through Win-Place Selector Switch to 'Win' Contact (Switch will be in Win Position if selector handle is in Win Position)
  6. From Win Contact on Issuer through Win Pole of No.22 Issuer Common Switch on Distributor Board through coil of No. 22 Win Relay, to No. 2 Stud of No. 2 Win Distributor.
  7. From Common ring of No. 2 Win Distributor to No. 2 Escapement on Win Grand Total Unit through No. 2 Escapement fuse, through Escapement Cutout Relay Contacts, Betting Circuit Fuse and Betting Circuit Switch.
  8. From Betting Circuit Switch on Win Grand Total Unit to Contacts of Win Contactor (which will be closed if Machine is open for betting) and thence to + side of Main Betting Circuit Switch.

When the Issuer Handle is depressed therefore, the circuit is complete except through the Distributor which completes the circuit as soon as it reaches No. 2 stud. No. 22 Win Relay will then instantly close and so maintain the circuit. The bet will be registered No. 2 Escapement of the Win Grand Total Unit and No. 3 Win horse Unit and the Issuer Trip Coil will function to start the Issuer and open the Betting circuit again.

The complete text from the company document titled titled Automatic Totalisators Limited Description of Electrical Circuit Diagrams can be read in another page in the Photo Gallery of this website. To read this click on the image then scroll down in the Photo Gallery index to the heading Figures from George Julius' White Paper 1920 and a Julius Tote Engineering Drawing with the first sentence of the descriptive text reading: This is a technical drawing showing Julius Tote interconnections and select the associated thumbnail.