The operation of the high frequency system does not differ in function action from the single spark system explained on the foregoing page. Either system may be had singly, or in duplex formation. Consequently either the single or the double system may be encountered. When the duplex system is used the driver has his choice and can use either the high frequency or single spark system, by turning the rubber roll switch on the distributor to the system indicated.
This follow-up feature has been found particularly advantageous for starting in cold weather, or where a poor grade of gasoline is encountered, and in case of a poor carburetor adjustment or foul spark plugs. The high frequency system also has the unique feature of keeping the spark plugs clean without disintegrating the electroids, as is often the case with the high tension magneto.
Fig. 83. Duplex High Frequency Switch
[Fig. 83] shows the Duplex switch. Ordinarily a storage battery is used for one source of current, and a set of dry cells for the other. This is so arranged that either source of current can be used with either the single spark system or the high frequency system at will. One source of current only can be used if so desired, that is, the storage battery only or the dry cells alone. Where the source of current is dry cells only, the single spark system is used as it is more economical in current consumption. All of the switch contacts are of the pressure plunger type, thereby eliminating the uncertainty of brush contacts. Each switch is provided with a lock operating through the hub of the lever. When the switch is locked in the off position it is impossible to remove the cover without breaking it as the cover of the switch locks to the back.
Ratchet buttons select which one of the systems is to be used, by a movement of 45°. This button operates only in a clock-wise direction.
| C-2 Circuit 2 C-1 Circuit 1 Bat.-1 Battery 1 Bat-2 Battery 2 Sec-Secondary C-Circuit Sec. Gr. Secondary Ground | ||||||
| To Spark Plugs | BAT. (SEC.GR.) C | |||||
| BAT.-2 | ||||||
| BAT.-1 | Coil | |||||
| C.R. | ||||||
| Distributor | ||||||
Fig. 84. Philbrin Wiring Diagram
[Fig. 84] shows a wiring diagram of the Philbrin system. The wire connections come to the contact maker directly from the switch, instead of from the coil. This provides for control of the current to the contact maker in such a manner that if a short circuit occurs in either of the systems, by turning a button it is entirely cut off and the other system put into operation.