Modern Fire Alarm Signalling
Gong and Joker Switchboards— Installation, Operation and Care
THIS is the tenth of a scries of articles on the care, installation and repair of various phases of fire alarm work. The author has had practical experience in this field, and he will answer questions on this subject that are submitted to him by the readers, free of charge. The only condition is that a stamped envelope must be enclosed for reply.
Description of Gong and Joker Boards
Gong and joker boards are equipped with the necessary apparatus to relay the alarms sent out from the fast and slow transmitters to the engine houses. Several engine houses are served by one circuit and the boards are built in any number of circuits as desired. It is necessary then that the boards be equipped with apparatus with which the alarm may be sent to the various engine houses or companies.
The apparatus on a gong board consists of the following parts for each circuit and the Joker board of the same apparatus. There are many names given to these boards namely, fast and slow time boards, primary and secondary, and joker and gong boards—the joker being the former and the gong the latter.
Each circuit has the following equipment:
i Green bullseye for joker and white for gong boards.
Circuit tell tale number annunciator.
4-inch umbrella type tapper either open or closed circuit type.
A detachable box listing frame.
A main line relay and necessary number of contacts.
A closed circuit key for joker board; an integral test key for gong board if of open circuit type.
Necessary cut out switches for tapper, light, key, annunciator, relay, and register.
A test jack for testing instruments etc.
A three point ground test switch.
Necessary gang switches to cut boards in for different transmitters or for manual key.
A restoring geared rack for resetting boards.
A ten-circuit gong or joker board is of about the same size as a ten-circuit relay or storage battery switchboard and can be obtained in either slate or marble panels. The relays are mounted in dustproof pockets to insure freedom from dust and dirt.
The boards are equipped with a manual resetting device, but on special order can be had in a remote control solenoid resetting device so that it is possible to reset the boards from the telephone desk or the operator’s pedestal.
When placing orders for gong or joker boards it is a good idea to order one with a few spare circuits so as to take care of future expansion of the office. If it is possible to have art metal cabinets in which to mount the boards it will be well to do so as it will permit the placing of glass doors on the back of the cabinet to keep all dust and dirt away from the working parts of the boards.
All relay contacts and the telegraph key contacts are of silver and all the finished parts are of the best grade of hard brass or bronze, and with a little care will give a great number of years of service.
The various switches are all marked at both ends of the hoards. The bullseye lights on these two boards are of the flashing type and flash once for each opening of the circuit, or if of the open circuit type, they will flash once for each making of the circuit.
Installation of Gong and Joker Boards
The boards should be installed in a clean dry place and should if possible be close together and not separated with any other type of boards in between them. The operators have to watch these boards so they should be placed in a position where it is possible to see them from the operating end of the office. They can be placed on iron pipe frames or in art metal cabinets. These give a better protection to the boards than the pipe rack and they are a neater looking job. The rack frame or art metal cabinet is set up and the board placed upon it and tightened. Care must be used in tightening up the bolts holding the board, and the board must be attached to the frame squarely or it will crack or break.
The boards should be protected from the direct rays of the sun to prevent discoloration; the brass parts will tarnish and have a dirty color as a result of this.
General instructions on the installations of all types of switchboards were given in a past issue and can be used for any type board described in these articles. A great number of wires terminate at these boards and special conduit construction will have to be worked at the time the boards are placed in position. It is necessary to feed the lights with 110 volts either direct or alternating current being suitable. The wiring on this circuit should be placed in rigid iron conduit and should be run in accordance with the fire underwriters rules. These lines hook on to the fuse blocks attached to the boards.
The lenses in the Joker boards are colored green ami in the gong board are white. Both lenses are about two inches in diameter and of clear cut glass. They give a strong clear light and can be seen for any normal distance.
All wiring or. the boards should be hooked up as is marked and you should check yourself on all connections before attaching them to the binding posts. The ground wires are common and one ground can be used on any number of boards. When you are tightening the connections on the backs of the boards be careful you do not strip the threads as it is very easy to do this or to turn the stud off.
The wires will have to be of the polarity as marked on the boards otherwise the circuit will fail, to function properly. It is not only necessary to have the correct pair but also the right leg on every stud on the boards. The terminals for the local battery are plainly marked and should be attached as shown on the print sent with the board. One local battery in some cases serves as many as three boards and it depends upon the local apparatus in the circuit as to how many batteries are needed.
if slate or marble kickplates and shelves are used, care should be taken in placing them on the boards. They should be shimmed up with cardboard and should not be tightened too tight. The shelf should not be used as a scat as it is not strong enough to sustain a great weight. These parts are for ornamental purposes and are not to he used as the regular equipment.
Operation of the Joker and Gong Boards
When an alarm of fire is received in the central offices, the fast and slow time transmitters are set up after the box has been verified with the tape record. At the proper time the transmitters are started and it is at this time that the joker and gong boards arc placed into use. With the two boards set for operation from the manual transmitter, and the transmitter set in motion the following takes place: the green and white lights on both boards will flash once for each blow; the 4-inch tapper will strike once for each opening or breaking of the circuit; the number annunciator will drop down and stay down on the first blow; the relay will operate and run the register the register punching once for each blow. Each circuit on the board will do as above described unless the circuit is cut out and it then can not of course operate.
Each time the circuit is interrupted a blow will he sent through to the engine houses as these boards work the same as the relay boards.
There is a telegraph signal key for each circuit awl it is used for special signaling between the engine houses and headquarters. Signals sent by these keys include those for extra companies. still alarms where only a certain number of companies arc to be notified, details of special men, time signals, and watch reports of stations. There is a key in each engine house and it is used to cut in the circuit so as to be able to call the central office as well as the central office calling the houses.
When repairing the fire house circuit lines, the repairmen call in to the office for directions and are answered over the signal key. There are six switches on this board and they are used for cutting out the different apparatus in order to allow repairs to be made without disturbing the operation of the office and
Main line registers are not used because of the amount of current needed for their safe operation. The registers are of the boards. A switch is provided to cut out of circuit the following named apparatus: tapper, relay, register, annunciator, light and manual key.
When changing reliefs it is well to have the man in charge go to each gong and taker board and see if any switches are in an out position. Note should be made at this time of any abnormal workings of the apparatus and the information should be entered in the record book—a man should be detailed to correct the condition. The operation of the registers should be checked at this time and should be wound up full. The registers will run lor a few hundred blows but it is best to wind it up every week. Or if alarms are numerous it should be wound up at every change of the watch. open circuit type awl are controlled by the main line relays. These relays require very little current and operate on a current as small as 30 milliamperes. They have very little mechanical work to do and are therefore better to use than the register.
The line current is apt to drop at any time and this is caused by grounds and many other causes. If the line current dropped and relays were not used, the registers would work if the line went as low as 80 milliamperes. The relay should be adjusted so as to attract at a current of 30 milliamperes. Care should be taken to see that the relay will work on this adjustment. The silver contacts should be cleaned with a fine piece of sandpaper or a dental file. Emery cloth should never be used under any circumstances. The board should be wiped with a prepared cloth and no polish should ever be used on any of the apparatus as it will tend to tarnish the finish. All silver contacts on the annunciator and key contacts should be kept bright and clean at all times to insure proper operation. All switch contacts should be brightened with a piece of fine sandpaper and the spring contacts on the switch arm cleaned in the same manner.
Whenever you are working on any apparatus cut it out of the circuit by means of the cut out switch. This enables one to work on the board without disturbing the continuity of the line in any way.
An electric light should be installed at the back of each board to permit the men to work on the boards at any time. The light should be set so as to point downward and it should be placed at the top of the board or cabinet. Use a separate supply for these lights and keep the line feeding the tell tale lights st parate.
Figure No. 24 shows a group of gong and joker boards as installed in a large central office. You will note that they are close to the manual transmitter and that the operator’s pedestal; here the operators work when sending out alarms. The registers and time stamps shown on the operators pedestal directly in the foreground are for the gong and joker circuits. You will note the proximity of all the operating apparatus and in order to transmit alarms as fast as possible, it is absolutely necessary to have the operating end of the office centralized.
The resetting device is a rack type geared handled bar which forces over the armature bar on the annunciator magnets. In the solenoid reset type the solenoid draws the bar over and tesets the board the same way as it is done manually.
The resistance of the following apparatus on the board is given to enable one to order replacements etc.
Bulls eye light—15 watts each.
Annunciator magnets-—80 ohms per pair.
Tapper magnets—40 ohms per pair.
Annunciator switch resistance—100 ohms.
Relay main line type—30 ohms.
Specifications for gong and joker boards are given in the last part of this article and are taken from specifications now in use. In ordering a new gong or joker boards these specifications can be used.
Wiring on the Back of the Switchboards
Our line comes from the protector board, positive side, to the tap bell switch contact and on to the tapper passing through the tapper and back to the opposite tapper switch contact. If the switch is on the circuit it continues on through the switch and down to the instrument jack passing.through the jack and to the proper switch on the transmitter transfer switch. The route of the circuit from here is dependent on the position of the transfer switch. For descriptive purposes we will assume that the switch is resting on the right hand contacts. The circuit now passes from the top of the switch to the contact and to the transmitter No. 1 coming back and going to the negative side of the switch contact and through the switch to the instrument jack on the protector board. We will now pick up the other half of the circuit starting at the same place we started on the positive section. We will now follow the negative side from the protector board to the relay switch, through the switch and contact, and on to the relay, passing through the relay and on to the key switch, through the key and on to the protector lx>ard. From there it goes as shown on the pin switch diagram in article No. 8. The local circuits are easily followed and will not be described in detail.
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Modern Fire Alarm Signaling
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Troubles and Their Remedies
The troubles that are most experienced will be taken up at this time and while other kinds of trouble may be experienced at anytime thev will not be as severe as the following. Before lookingfor trouble, should only one piece of apparatus fail to work, it will lie well to look and see if the switch which cuts out that instrument is not in a cut out position.
Bulls eye light fails to light—Lamp burnt out and needs to be replaced; dirty’ contacts on hook switch—clean to correct trouble.
Annunciator trip stuck—clean and tree trip.
Broken wire in circuit—locate and correct.
Blown fuses in fuse block—replace fuses with new ones.
Bulls eye light stays lighted—Board has not been reset—reset board to correct.
Contactor is stuck—free and clean.
Line open outside or inside—test out and close line.
Annunciator number stays down—Board has not been reset reset board to correct.
Line open inside or outside—close line to correct. Annunciator magnets open—locate and repair.
Tapper will not strike—Switch is in an off position—put switch in proper position.
Magnets are permanently magnetised—break down the magnetism with A.C. or any other means.
Striking rod is bent—straighten rod to free it.
Resistance is open—replace resistance.
Tapper strikes occasionally—Swinging open line—close line to correct.
Fluctuating battery—locate and repair.
Relay works slow—Spring tension too tight—loosen tension to correct.
Line current weak and relay works slow—build up line to 100 milliamperes.
Relay sticky and holds—Pivot screw too tight loosen to correct.
Residual magnetism—break down magnetism.
Dirty armature—clean armature.
Telegraph key does not operate—Switch is in an off position close switch to correct.
Key stuck—release key.
Guard is over key—release guard.
Register keeps running—-Incorrect adjustment of relays— make proper adjustment.
Line open—test out and close line.
Register switch in wrong position-—set switch properly.
Main line works but local apparatus will not work—Local battery fuse blown—replace with new’ fuse.
Local battery low or fluctuating—build up battery’ to normal.
Transmitter runs but board will not work—Board is set for semi-automatic operation or for reserve transmitter set board for transmitter you are using. Do not do this until the transmitter stops.
Whenever you are testing or hunting trouble on any boards such as described above, always notify the man on watch of ymur intentions in order to avoid any’ misunderstanding. henever you are replacing any lamps, resistances or any equipment on these boards be sure you put the proper size in place of the old one. Larger w’attage lamps than 15 watts arc unnecessary as the small ones give plenty of light on an alarm. On open circuits which have been traced as far back as these boards, always look at the contacts and switches for any loose contacts, the instrument jack contacts, keys and relay.
Always keep the key guards over the keys to prevent the striking of a stray blow at any time. Keep all moving parts bright and clean at all times. Keep all dust and dirt away from the relays, etc. If ever you are repairing or doing anything where a lot of dust will rise, make special arrangements to protect all part of the boards.
Specifications for Gong and Joker Boards
The switchboard panels shall be made of the best grade of (marble or slate) free from all metalic veins and hard spots and the boards shall ho mounted in (art metal cabinets or iron pipe frames) as desired.
Each gong or Joker line circuit shall be equipped with the following devices.
t bronze panel located at the top of the board, carrying a z inch (green or white bulls eye light) number plate and line circuit annunciator.
t 4 inch main line umbrella type gong.
t detachable fire department section number list frame.
t main line relay enclosed in glass dust proof receptacle.
t set or relay and register local switches.
i main line closed circuit telegraph key.
t set of tapper and annunciator switches.
t standard telephone jack tor the insertion of testing instruments or portable telephone set.
t three-point ground switch.
Each panel or unit of the tjoker or gong board) shall be pro vided with the necessary name and indication plates placed at both ends of the board in a line with the apparatus.
Each board shall be equipped with the necessary gang switches to allow shifting the method of operation etc.
All above boards shall be identical in size and finish and shall harmonize with each other.
Any questions on Gong or Joker boards will be answered as promptly as is possible.
The next article will take semi-automatic operation and semi automatic operators’ pedestals.