This Siemens 3SB3251-0AA21 pushbutton unit is a pilot device with a flat, red illuminated pushbutton actuator with momentary contact and an integrated LED bulb. It is made of plastic for corrosion resistance and non-conductivity. The pushbutton actuates the normally open (NO) and normally closed (NC) contacts, and the contact blocks are rated up to 130V and up to 10 amp. The unit has an operating temperature range from -25 to +70 degrees C and meets the Ingress Protection (IP) 66 standard for protection against dust and spraying liquids. This pilot device is Underwriters Laboratories (UL) listed, Canadian Standards Association (CSA) certified, and displays the European Conformity (CE) and EurAsian Conformity (EAC) marks.
|Contact blocks||1 NO + 1 NC|
|Supply voltage of lamp||110V AC|
|Minimum to maximum voltage||100 – 130V AC|
|Maximum current||10 amp|
|Maximum operating cycle||1,000/hr|
|Operating temperature range||-25 to +70 degrees C|
|Specifications met||UL listed, CSA certified, CE and EAC marked|
|Mounting dimensions*||8 x 22mm (H x Dia.)|
|Installation dimensions*||28.5 x 63mm (W x D)|
*H is height, the vertical distance from the lowest to highest point; Dia. is diameter, the length of a straight line passing through the center of the button; W is width, the horizontal distance from left to right; D is depth, the horizontal distance from front to back.
Pushbutton switches make or break electrical connections as part of a system that controls a process, such as a manufacturing line. Indicator lights with labels or color-coded caps are used to display the current state of a process, such as "completed." The pushbutton unit is composed of a pushbutton actuator for making or breaking electrical connections, a holder for securing the actuator to a control panel and for housing a light, and one or more contact blocks for connection to electrical wiring. Contacts within a contact block can be normally open (NO) or normally closed (NC), so that pressing the button starts or stops a process. Holders accommodate a range of control panel thicknesses and may include lamps to illuminate the button. Pushbutton actuator head types include mushroom, flat-surface, raised-surface, and key-operated, and may be illuminated, color-coded, and labeled. According to the requirements of an application, actuators may operate only as long as the button is held or they may lock into position when pushed and unlock when pulled or twisted. Pushbuttons and indicator lights are used in applications such as manufacturing process controls and as emergency shutoffs in industrial workplaces.
Siemens manufactures electronic products for building automation, industrial drives, lighting, energy generation, medical equipment, and rail transportation. The company, founded in 1847 and headquartered in Munich, Germany, meets International Standards Organization (ISO) standards 14001, 9001 and TS 16949.