Siemens 3UA7021-1A Industrial Safety Relay Module

Siemens 3UA7021-1A is an industrial safety relay module designed to guard motor circuits and protect personnel by interrupting the control path in overload or fault conditions. As part of the 3UA7 family, this unit represents a basic safety relay module with a single normally open contact and a built-in test button for functional verification without removing power from the machine. It is intended for integration into Siemens-based safety architectures and motor-protection schemes, serving as a signaling element that can drive interlocks or safety controllers when an overload is detected. Typical applications include machine tools, conveyors, pumps, fans, and other automated equipment where a compact, single-channel overload/relay solution is appropriate for safeguarding active drive circuits. The 3UA7021-1A is aligned with Siemens’ safety relay concepts, enabling straightforward wiring into standard control circuits and providing a clear safety signaling path to downstream logic or safety modules. Because it relies on a single signaling channel and a manual test mechanism, it is well-suited for straightforward motor-protection tasks within modular safety assemblies, offering a reliable option for basic protective interlocking and fault signaling in industrial environments.