Uses of a Silicon-Controlled Rectifier
- A DC (direct current) motor is one of the earliest machines that can convert electrical power to mechanical power. It uses an SCR to control the amount of electricity that will be converted into mechanical power. DC motor circuits allow electrical current to be manually interrupted by a simple button push to facilitate resetting of the SCR. This is particularly useful when administered to pure DC circuits in alarm or trip circuit latching. The driving voltage of a DC motor controls its speed of rotation and the amount of mechanical power it releases.
The most common types of DC motors include the wound field or permanent magnet motors, DC brush and brushless motors, and series wound DC motors. DC motors can be found in servomotor-based hand drills and kitchen appliances, robotics and automotive (brakes) applications. - A Solid State Relay (SSR) is an electronic device that facilitates the on/off function of a particular machine or electronic appliance. It typically uses several semiconductors, such as an SCR, to facilitate the on/off function flawlessly. Solid state relays require low facilitation of circuit energy to switch from on to off and vice versa, thus output power is significantly larger compared to control energy. SSRs are used in temperature control and measurement devices, flow and level indicators and meters, conductivity and pH instrumentation, heaters, and pressure and strain gauges.
- AC (alternating current) motors typically have two SCRs connected in inverse parallel structures, technically producing back-to-back switches. This configuration allows the motor to have a bidirectional capacity to “move” electricity.
AC motors have three major configurations: stud mounted, module and disc or hockey puck. Modern controllers use the latter two types. Higher current applications requiring satisfactory semiconductor cooling use the hockey-puck system configuration. SCR modules have the SCR enclosed within a plastic containment unit bundled into a mounting plate. These types provide relatively better surge current capacities. - Solid-state lighting systems (light dimmers) rely on the duty cycle of the On-Off switch to facilitate control of lights through full AC voltage application. Such systems have a knob to control brightness settings and determine at which point to switch lights off and on. An SCR trigger causes continuous current passage until all current has been used up. Duty cycles are changed by altering the stages of triggering the SCR, therefore producing light dimming at specified points. This configuration necessitates the presence of a fuse to protect against transmission failures.
