Solenoids

Solenoids * Solenoids or coils: These are found in every modern pinball machine since the flipper age.

The smaller, lower-powered solenoids were first to be transistorized, followed later by the higher-current solenoids as the price, performance, and reliability of power transistors improved over the years.

Very early games used low-voltage AC power for solenoids, requiring fewer components, but AC is less efficient for powering solenoids, causing heavier wiring and slower performance.

Moreover, inspecting the solenoids, shift sensors, and valve bodies requires lifting the car and draining all the old ATF.

More than 20 years ago, NABCO, Inc. held its grand opening celebration at the building, where it re-manufactured starters, alternators and solenoids for the automobile industry.

All but very old games use low DC voltages to power the solenoids and electronics (or relays).

All solenoids and coils used on microprocessor games include a special reverse-biased diode to eliminate a high-voltage pulse of reverse EMF ( electromotive force ).

As electronics were gradually implemented in pinball design, solenoids began to be switched by power transistors under software control to lower switch voltage and current, vastly extend switch service lifetime, and add flexibility to game design.

At the low extreme of size is the concept of micro-SMES solenoids, for energy storage range near 1 MJ.

A typical pinball machine I/O mix includes 16 to 24 outputs for driving solenoids, motors, electromagnets and other mechanical devices in the game.

Early pinball machines typically had full solenoid current passing through trigger switches for all types of solenoids, from kickers to pop bumpers to the flippers themselves.

For locations that suffer from low AC wall outlet voltage, additional taps may be provided on the AC transformer in electromechanical games to permit raising the game's DC voltage levels, thus strengthening the solenoids.

For small SMES, solenoids are usually used because they are easy to coil and no pre-compression is needed.

In traditional superconducting solenoids, liquid helium is used to cool the inner coils because it has a boiling point of around 4 K at ambient pressure.

Modern equivalents of the player piano include the Bösendorfer CEUS, Yamaha Disklavier and QRS Pianomation, citation using solenoids and MIDI rather than pneumatics and rolls.

Older electromechanical game solenoids do not require this diode, since they were controlled with mechanical switches.

Solenoids also control pop-bumpers, kickbacks, drop target resets, and many other features on the machine.